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Heat Pump Service 1.

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Presentation on theme: "Heat Pump Service 1."— Presentation transcript:

1 Heat Pump Service 1

2 HEAT PUMPS TOTAL ELECTRIC UNIT CAPABLE OF PROVIDING HEATING AND COOLING MOVES HEAT WITH REFRIGERATION SYSTEM. CURRENT TECHNOLOGY ALLOWS US TO ABSORB ENERGY FROM THE OUTDOOR AIR EFFICIENTLY, DOWN TO 20º. 2

3 Then releases the heat (energy) into the indoor air.
During the winter months the heat pump absorbs heat from the outdoor air. Then releases the heat (energy) into the indoor air. There is energy (heat) present to minus 460º. Just as it is more efficient to move an object than it is to build or make one. It is more energy efficient to move heat, than generate it (depending on thermal/economic balance points). 3

4 Heat pumps are sized for the cooling demand of the application.
The heat pump will be the sole source of cooling for the application. It may be the only source of heat, depending on heating requirements. Most areas of the country will also require an additional source of heat. This may be as little as a 5KW heat strip, or as much as a 80,000 BTU furnace. We’ll look at this in more detail later. 4

5 HEAT PUMPS COOLING SEASON
HEAT PUMP PERFORMS THE SAME AS ANY AIR CONDITIONING SYSTEM BY PICKING UP HEAT FROM THE SPACE TO BE CONDITIONED AND REJECTING IT OUTDOORS 5

6 HEAT PUMPS HEATING SEASON
UNIT ABSORBS HEAT FROM THE OUTDOOR AIR AND MOVES IT TO THE CONDITIONED SPACE REVERSE-CYCLE AIR CONDITIONERS 6

7 HEAT PUMPS CLASSIFIED BY: THE SOURCE OF HEAT DURING THE HEATING CYCLE AND THE MEDIUM TO WHICH THE HEAT IS TRANSFERRED AIR-TO- AIR WATER-TO-AIR 7

8 INSIDE THE HEAT PUMP COMPRESSOR CAPABLE OF OPERATING AT LOW OUTDOOR TEMPERATURES INDOOR / OUTDOOR COIL DESIGN METERING DEVICE FOR INDOOR / OUTDOOR COIL REVERSING VALUE ( 4-WAY VALUE ) ACCUMULATOR CRANKCASE HEATER AUXILIARY HEAT EMERGENCY HEAT DEFROST CYCLE 8

9 HEAT PUMP ACCUMULATOR WHY HAVE ONE? MOST IMPORTANT:
CLIMATUFF - PART OF COMPRESSOR SHELL LOCATED IN SUCTION LINE BETWEEN THE COMPRESSOR AND REVERSING VALUE WHY HAVE ONE? MOST IMPORTANT: HEATING CYCLE - COLD TEMPERATURES, OUT DOOR COIL MAY NOT BE ABLE TO EVAPORATE ALL THE REFRIGERANT END OF DEFROST CYCLE LIQUID CARRYOVER WILL BE CAUGHT BY THE ACCUMULATOR TO PREVENT COMPRESSOR DAMAGE 9

10 WHAT MAKES A HEAT PUMP UNIQUE
SPECIAL COMPRESSOR MUCH HIGHER COMPRESSION RATIO MOST SEVERE APPLICATION HEAT PUMP COILS ALTERNATELY FUNCTION AS EVAPORATOR AND CONDENSER MUST TOLERATE CHARGE IMBALANCE OUT DOOR COIL MUST BE DESIGNIED FOR EASY DEFROST 10

11 HEAT PUMP CRANKCASE HEATER
LOCATED ON COMPRESSOR, OLDER SYSTEMS USED COMPRESSOR WINDINGS. RAISES TEMPERATURE OF OIL SO THAT THE ABSORPTION OF REFRIGERANT INTO THE COMPRESSOR IS KEPT TO A MINIMUM 11

12 COOLING CONDITION INDOOR COIL OUTDOOR COIL SAT. SUCT. T. 41F
ENT. AIR T F 4-WAY VALUE SUCT. P. 70 PSIG SUCT. T. 52F SUPERHEAT 11F METERING DEVICE SUBCOOLING 10F DISCHARGE PRESSURE 260 PSIG OUTDOOR COIL SAT. COND. T. 120F ENT. AIR T F COMPRESSOR 12

13 HEATING CONDITIONS INDOOR COIL OUTDOOR COIL SAT. COND. T. 95F
ENT. AIR T F 4-WAY VALUE METERING DEVICE SUBCOOLING 10F METERING DEVICE SUBCOOLING 10F SUCT. P. 43 PSIG SUCT. T. 35F SUPERHEAT 10F DISCHARGE PRESSURE 182 PSIG OUTDOOR COIL SAT. SUCT. T. 20F ENT. AIR T F COMPRESSOR 13

14 HEAT PUMP TOTAL HEAT REJECTED EQUALS
HEAT ABSORBED HEAT OF COMPRESSOR 14

15 HEAT PUMP THE REVERSING VALUE CONTROLS THE DIRECTION
THE REFRIGERANT FLOWS 15

16 COOLING CONDITION INDOOR COIL OUTDOOR COIL SAT. SUCT. T. 41F
ENT. AIR T F 4-WAY VALUE SUCT. P. 70 PSIG SUCT. T. 52F SUPERHEAT 11F METERING DEVICE SUBCOOLING 10F DISCHARGE PRESSURE 260 PSIG OUTDOOR COIL SAT. COND. T. 120F ENT. AIR T F COMPRESSOR 16

17 HEATING CONDITIONS INDOOR COIL OUTDOOR COIL SAT. COND. T. 95F
ENT. AIR T F 4-WAY VALUE METERING DEVICE SUBCOOLING 10F METERING DEVICE SUBCOOLING 10F SUCT. P. 43 PSIG SUCT. T. 35F SUPERHEAT 10F DISCHARGE PRESSURE 182 PSIG OUTDOOR COIL SAT. SUCT. T. 20F ENT. AIR T F COMPRESSOR 17

18 Heat pump Thermostats Thermostats with adjustable heat anticipation need to have it adjusted for proper operation! 18

19 BAYSTAT239 OR 240 HEAT PUMP THERMOSTAT
F HEAT COOL OFF O HA BAYSTAT239 OR 240 HEAT PUMP THERMOSTAT CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T TSH W BL U RD B R 19

20 SHOW ME CLICK Fault Indication Light F O Y X2 G T W
HEAT COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T TSH W BL Thanks Glen. I’m James Jarman, Product Specialist for Tyler Product. We have listened to the customer’s complaint and calmed down the customer. Before we get into troubleshooting this problem, let’s check the anatomy of a heat pump thermostat.We need to understand how a thermostat functions, before we can decide how to service this system. I didn’t include a diagram in your literature package, but if you look in the SERVICE PROCEDURES HANDBOOK on page 5, figure for the BAY28X139 thermostat, you can see the internals of a thermostat similiar to the one on the screen. That’s in the Service Procedures Handbook, page 5, figure for the BAY28X139. First, lets find out the function each of the terminal , then we’ll trace out which circuits are powered and when. These internal drawings will be kinda crowded, so I am going to challange each of you to pay close attention to the location where I am referring. Most of the important locations internal on the stat will be tagged with a dotted red circle. The “F” terminal is the light for fault indication. The time it comes into play is when using the full featured defrost board. It will indicate when the defrost board detects a defrost fault and will cause the red led to flash. CLICK U RD SHOW ME B R 20

21 Fault Indication Light SOV Energized In Cooling
HEAT COOL F O Y X2 G T W U B R OFF RHS-1 NORM TS SM-2 RHS-2 FAN AUTO ON HA CA BL RD TSH C1 H1 ODA Fault Indication Light SOV Energized In Cooling The next terminal is “O”. This provides power for the switchover valve on a cooling call. 21

22 Fault Indication Light SOV Energized In Cooling
HEAT COOL OFF SOV Energized In Cooling O HA CA Brings On Compressor In Both Heating And Cooling Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T TSH W BL The compressor is powered by the “Y” circuit. This can be in either the heating or cooling mode. It will “make” the compressor contactor. U RD B R 22

23 Fault Indication Light SOV Energized In Cooling
HEAT COOL OFF SOV Energized In Cooling O HA CA Brings On Compressor In Both Heating And Cooling Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T TSH W BL “X2” provides the circuit that brings on the Emergency Heat. The other end of “X2” at the outdoor unit will bring on the auxillary heat during defrost. U RD B R 23

24 Fault Indication Light SOV Energized In Cooling
HEAT COOL OFF SOV Energized In Cooling O HA Brings On Compressor In Both Heating And Cooling CA Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 Brings On Indoor Fan ON RHS-2 NORM T TSH W BL The indoor fan will be cycled with “G” U RD B R 24

25 Fault Indication Light SOV Energized In Cooling
HEAT COOL OFF SOV Energized In Cooling O HA Brings On Compressor In Both Heating And Cooling CA Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 Brings On Indoor Fan ON RHS-2 Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’stats NORM T TSH W BL The “T” terminal is part of the heat anticipation circuit. It is used on Trane Thermostats to put a thermister in the outdoor unit, in series with a resistor in the thermostat. As the outdoor temperature drops, the voltage across the resistor in the thermostat drops, causing the thermostat to think its colder than it actually is. This causes it to keep calling for heating. U RD B R 25

26 Fault Indication Light SOV Engerized In Cooling
HEAT COOL OFF SOV Engerized In Cooling O HA Brings On Compressor In Both Heating And Cooling CA Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 Brings On Indoor Fan ON RHS-2 Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’stats NORM T TSH This Is The Second Stage-Brings On The Electric Heat W BL “W” is the second stage of this thermostat, it will bring on the Auxillary heat. U RD B R 26

27 Fault Indication Light SOV Engerized In Cooling
HEAT COOL OFF SOV Engerized In Cooling O HA Brings On Compressor In Both Heating And Cooling CA Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 Brings On Indoor Fan ON RHS-2 Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’stats NORM T TSH This Is The Second Stage-Brings On The Electric Heat W BL All “U” does is provide an internal connection to the “BLUE” LED. This gives a visual indication at the thermostat that the Auxillary heat is on. U Functions As An Internal Connection For The Blue Light RD B R 27

28 Fault Indication Light SOV Engerized In Cooling
HEAT COOL OFF SOV Engerized In Cooling O HA Brings On Compressor In Both Heating And Cooling CA Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 Brings On Indoor Fan ON RHS-2 Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’stats NORM T TSH This Is The Second Stage-Brings On The Electric Heat W BL The common side of the transformer in the indoor unit is “B”. The purpose of “B” is to provide the common side of 24 volt power for the Blue and Red LED’s U Functions As An Internal Connection For The Blue Light RD B This Is The Common Side Of The Transformer R 28

29 SHOW ME CLICK Fault Indication Light SOV Engerized In Cooling
HEAT COOL OFF SOV Engerized In Cooling O HA Brings On Compressor In Both Heating And Cooling CA Y NORM C1 TS RHS-1 H1 COOL Energizes Auxiliary Heat When Unit Is In Defrost X2 HEAT AUTO G ODA FAN SM-2 Brings On Indoor Fan ON RHS-2 Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’stats NORM T TSH This Is The Second Stage-Brings On The Electric Heat W BL And last but definitely not least is “R”. R-ahhhhh is the other side of the 24 volt circuit. It is the power that is switched inside the thermostat to make everything else work. We have identified the internal terminals and know which wires attach where- so THAT’S ALL WE NEED TO KNOW!!!!!! RIGHT???? WRONG!!!! To properly troubleshoot a thermostat, we need to know more- SO CLICK U Functions As An Internal Connection For The Blue Light RD B This Is The Common Side Of The Transformer SHOW ME This Is The Other Side Of 24 Volts From The Transformer R 29

30 BAYSTAT239 OR 240 HEAT PUMP THERMOSTAT
F HEAT COOL OFF O HA BAYSTAT239 OR 240 HEAT PUMP THERMOSTAT CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T TSH W BL Now let’s talk about this thermostat and see how it actually works. Here’s that same stat we looked at a few minutes ago. Let’s walk through the circuits one at a time. I know, many of you already know how it works, but let’s be sure. Since changing thermostats is so easy, we get hundreds back, and we can’t find any problems with them. So, understanding how the circuits work, MAY help diagnois some problems. U RD B R 30

31 First, let’s tie in a air handler low voltage circuit
HEAT COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T INDOOR UNIT R B G W1 TSH W BL First, let’s tie in a air handler low voltage circuit “B” from the air handler to “B” on the thermostat. And “R” on the air handler to “R” on the stat. U RD B R 31

32 F HEAT COOL OFF O HA CA FAN ON - ON Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G ODA FAN SM-2 ON RHS-2 NORM T INDOOR UNIT R B G W1 TSH W BL Now here’s where those dotted red circles I was talking about come in. See where the “fan” switch has moved to “ON”? With the fan switch on on, the circuit is completed back to the fan relay on “G” and I put in that circuit in green. Now, let’s add the “W” circuit and the cooling unit and go back to automatic fan operation. U RD B R 32

33 COOLING ON FAN - AUTO F O Y X2 G T W
BAYSTAT240A F COOLING ON FAN - AUTO HEAT COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G FAN SM-2 ON RHS-2 NORM ODA T TSH W BL Let’s go to cooling with the fan on auto. The lines in red are the circuits inside the thermostat that are engerized. The dotted red circles are the switches that have changed. “R” goes into the stat, through the “Mode Selection Switch”, through the mecury bulb to “Y” and also goes to “G” through the “Fan Selector Switch.” This brings on the compressor. The act of moving the “Mode Selection Switch” also engerized “O” that powers the switchover valve. U INDOOR UNIT R B G W1 RD B R COOLING ON FAN - AUTO 33

34 R Y X2 O BL Defrost Board ODS-A R/W OUTDOOR UNIT BAYSTAT240A F HEAT COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G FAN SM-2 ON RHS-2 NORM ODA T TSH W BL I know this next slide is a very, very busy picture - but it’s what we as servicer’s need to troubleshoot- WE NEED TO MENTALLY SEE THE WHOLE PICTURE By adding the outdoor unit control circuit, we can see what circuits are energized. “B” (common) gives one side of 24 volts to the outdoor unit and “R” gives the other side of 24 volts to the defrost board to close the Outdoor Fan Relay (located on the defrost board). “O” gives power to energize the switchover valve through the thermostat (“Mode Selection Switch” on Manual Changeover thermostats and 1st stage bulb in Autochange Over thermostats. “Y” from the thermostat gives 24 volts to energize the compressor. CLICK U INDOOR UNIT R B G W1 RD SHOW ME B R COOLING ON FAN - AUTO 34

35 HEATING - ON - FIRST STAGE FAN - AUTO
COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G FAN SM-2 ON RHS-2 NORM 15 TO 22 VOLTS (T) FROM ODS-A TO (R) ODA T TSH W BL When we switch to the heating mode, the Switchover Valve is dropped out , putting the outdoor unit in heating and NOW the “T” circuit will come into play. We’ll talk about “T” in detail in a few minutes. U RD B R 35

36 Let’s add the indoor control circuit.
BAYSTAT240A F HEAT COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G FAN SM-2 ON RHS-2 NORM ODA T TSH W BL Let’s add the indoor control circuit. The circuits that are powered in the thermostat are in red. The switches that are used are in the infamous dotted red circles. INDOOR UNIT U G RD B B W1 R R 36

37 OUTDOOR UNIT BAYSTAT240A Defrost Board F HEAT COOL OFF O HA CA R Y NORM C1 TS Y RHS-1 R/W H1 COOL X2 X2 HEAT O AUTO BL G FAN BL SM-2 ON RHS-2 Y NORM O ODA T ODS-A TSH W BL Now lets add the circuits of the outdoor unit. The diagram gets a little busy, but I think you can make out which of the circuits are powered. That’s the ones in color. There is 24 volts coming into the t’stat on “R”, through the “Mode Selection Switch”, through the “NORMAL” switch of the “Emergency Heat Switch” to “Y” which goes to the outdoor unit and powers the compressor contactor. The “R” circuit also goes through the fan “AUTO” switch. There is also a circuit completed to the “T” terminal. That, we’ll talk about further in a few more slides. INDOOR UNIT U G RD B B W1 R R 37

38 HEATING - ON - 2ND STAGE FAN - AUTO F O Y X2 G T W
COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G FAN SM-2 ON NORM RHS-2 15 TO 22 VOLTS (T) FROM ODS-A TO (R) ODA T TSH W BL When the room temperature drops 1 1/2 degrees below set point, the second stage of heating is engerized. This will bring on the auxiliary heat through the Heating mercury bulb (TSH) and also engerizes a blue light on the t’stat that gives an indication that the auxilary heat is on. U RD B R 38

39 Now let’s look at the thermostat.
F HEAT COOL 24 VOLT S (O) FROM DEF. BRD OFF O HA CA Y NORM C1 TS RHS-1 24 VOLT S (X2) FROM DEF. BRD H1 COOL X2 HEAT AUTO G FAN SM-2 ON RHS-2 15 TO 22 VOLTS (T) FROM ODS-A TO (R) ODA NORM T TSH W BL Now let’s look at the thermostat. There is a voltage feed on “O” , but it doesn’t go anywhere. There is volts on “X2”, but again, it doesn’t complete any circuits in the thermostat. And we’ve already discussed what “T” is for. U RD B R 39

40 (OPERATES 1.5° BELOW SETPOINT)
HEATING ON EMERG. HTG (OPERATES 1.5° BELOW SETPOINT) FAN - AUTO BAYSTAT240A F HEAT COOL OFF O HA CA Y NORM C1 TS RHS-1 H1 COOL X2 HEAT AUTO G FAN SM-2 ON RHS-2 NORM ODA T TSH W BL If there is a malfunction of the outdoor unit, these thermostat can be put into the “EMERGENCY HEAT MODE”. With this feature, heat can be obtained, but the thermostat will operate 1 1/2 degrees below set point. By moving the emergency heat switch, “Y” for the compressor is locked out of the circuit, but the auxillary heat will function normally. INDOOR UNIT U G RD B B W1 R R 40

41 WHAT IS COOLING DROOP? Cooling droop is caused by the cooling anticipator heating up during the off cycle, causing the t’stat to come on sooner, to help overcome the thermal lag of the system. This also provides night time cooling that helps keep humidity under control I’ve been talking a lot about the circuits of a thermostat. What about some of the things you will see a thermostat do? One is a phenomenon called DROOP. Droop can occur in both the cooling mode and in the heating mode. Cooling droop is caused by the cooling anticipator heating up during the off cycle, adding heat and causing the t’stat to come on sooner. This helps to overcome the thermal lag of the system. It also provides cooling at night that helps keep humidity under control. 41

42 DROOP (cont’) Then there is Heating Droop.
Heating Droop moves the temperature in the wrong direction. To compensate for this, the “T” circuit is added. Then there is heating droop. Heating droop moves the room temperature in the wrong direction. To compensate for this, we have added the “T” circuit. 42

43 WHAT DOES THE “T” CIRCUIT HAVE TO DO WITH ANYTHING?
The “T” circuit is a heat anticipation circuit that adds heat to the thermostat to slow down thermostat response, and removes heat to speed up the response. What does the “T” circuit have to do with anything? Well, let’s explore “T” and what it does. “T” is a heat anticipation circuit that adds heat to the thermostat to slow down thermostat response and removes heat to speed up the response. Remember, “T” is active in the Heating Mode. 43

44 “T” Circuit As the outdoor temperature drops, the resistance in the “T”, actually a thermistor (ODS-A), goes up. The higher the resistance, the less voltage is supplied to the resistor (ODA) located inside the thermostat. The less voltage to the ODA, the colder the t’stat thinks it is. As the outdoor temperature drops, the resistance in the ODS-A goes up. The higher the resistance, the less voltage is supplied to the resistor ODA located inside the thermostat. The less voltage to the ODA, the colder the t’stat thinks it is. 44

45 DEFROST THERMISTOR RESISTANCE
10000 9000 8000 7000 6000 RESISTANCE 5000 4000 3000 Just for grins, heres a plot of the resistance vs temperature of the thermistor. Notice how fast the resistance changes below 35 degrees. 2000 1000 75 -40 35 115 OUTDOOR TEMPERATURE 45

46 ODS-A 4000 .0034 A -20°F 3000 13.6 V 10.4 V .047 W ODA .036 W Now let’s look at how the ODS-AS and the ODA interact. Glen will talk about the measurement locations a little later, but these schematics give what the voltage changes effect. Notice the voltage at the ODS-A, it 13.6 volts. This is a result of the low outdoor temperature. This relatively high voltage on the thermistor, gives a low voltage of 10.4 volts across the ODS resistor. 46

47 4000 .0034 A -20°F 3000 ODS-A 13.6 V 10.4 V .047 W .036 W ODS-A 2000 .0048 A 0°F 3000 9.6 V 14.4 V .046 W .069 W As the outdoor temperature warm to O degrees, look at the voltage across the outdoor thermistor. It’s 9.6 volts while the voltage across ODS is 14.4 volts. More voltage to the resistor equal more heat, equal shorter run time. 47

48 4000 .0034 A -20°F 3000 13.6 V ODS-A 10.4 V .047 W .036 W 2000 .0048 A 0°F 3000 ODS-A 9.6 V 14.4 V .046 W .069 W ODS-A .0063 A 800 3000 30°F 5 V 19 V With the outdoor temperature warming to 30 degrees, the volts drop to 5 and goes to 19 at the ODS. Again more volts, more heat, shorter run time. .031 W .119 W 48

49 4000 .0034 A -20°F 3000 13.6 V ODS-A 10.4 V .047 W .036 W 2000 .0048 A 0°F 3000 ODS-A 9.6 V 14.4 V .046 W .069 W .0063 A 800 3000 30°F ODS-A 5 V 19 V What happens at 70 degrees? The resistance of the thermistor has dropped very low and the volts have also dropped at the thermistor. The maximum heat from the resistor has almost been achieved. This is the reason that without the “T” circuit, the thermostat is out of calibration, even in the cooling mode. The heat from the resistor is IMPORTANT to maintain thermostat calibration. Without it these thermostat will be 5 to 6 degrees out of calibration. .031 W .119 W ODS-A .0073 A 300 70°F 3000 2.2 V 21.8 V .013 W .159 W 49

50 DEFROST BOARD DURING DEFROST
K2 OD Motor 230 VOLTS BR/BL T’STAT R R Y Y K1 RD/W F BK X2 O O T B BL COMPR Y SOV O Now let’s see what happen when the unit goes into the defrost sequence. This is the internals switches and terminals on one of our electronic defrost boards. Most activity during defrost takes place in the outdoor unit and the defrost board. First the Switchover valve is enerized through the defrost board and puts the system into cooling The outdoor fan relay on the defrost board opens and turns off the outdoor fan. Next the X2 is powered to provide power to energize the auxillary heat. Then, T AMB. SENSORS COL T 50

51 WHY IS THE BLUE LIGHT ON? One of the feature on these thermostats, is also one of the most ignored and mis-understood features. This is the blue light, that glowing on the thermostat during the heating mode. 51

52 THE BLUE LIGHT IS AN INDICATION THAT THE AUXILIARY HEAT IS ON.
It is on in several instances. If the t’stat is adjusted above set point. If the outdoor temperature is below 40°F it will cycle off and on to maintain room temperature. If it stays on constantly above 30°F or cycles on when the outdoor temp. is above 50°F, the system should be checked. There is several reasons a consumer should pay attention to the blue light. It can come on when the thermostat is manually adjusted above the set point. This is an indication that the auxillary heat is on. This practice can drive up a utility bill. Next, it can cycle on if the outdoor temperature is below around 40 degrees. This is to maintain room temperature. If the blue light stays on constantly above 30 degrees or cycles on when the outdoor temperature is above 50 degrees, the system should be checked. The heat pump is not performing as it should. Attention to the blue light could prevent higher than necessary utility bills should the outdoor malfunction. 52

53 WHY IS THE RED LIGHT ON STEADY?
Another question that is often asked, is why is the red light glowing on my thermostat. 53

54 The Red Light on steady is an indication the Emergency Heat Switch is on.
The switch is used only if the heat pump is inoperative, but not due to a power failure. Using the heating in this mode will increase your power consumption. The red light is to remind the customer that the temperature is being controlled by resistance heat only. A steady red light means the thermostat has been switched to the EMERGENCY HEAT MODE. This means the heat pump is NOT operating, but there is voltage to the indoor unit. The use of emergency heat WILL increase your power consumption. The red light is a reminder to the customer that the temperature is being controlled by resistance heat. 54

55 THE RED LIGHT ON, BUT IT IS FLASHING
The Emergency Heat switch is in the Normal position. Another question is: The red light is on, but it is flashing. What does that mean? 55

56 RED LIGHT FLASHING If the red light is flashing, this is an indication that the defrost board has detected a defrost fault. Reset by moving the Emergency Heat Switch to the “on” position for 30 seconds. If the flashing returns, service on the heat pump may be required. The flashing red light is a indication that the defrost board has detected a malfunction in the defrost features of the heat pump. The light may be cleared by putting the unit into Emergency Heat Mode for about 30 seconds. If the flashing light does not return shortly, the malfunction may have cleared itself. We will discuss defrost problems during another broadcast. If the flashing returns, service on the heat pump may be required. Now that you are intimately knowledgable with the functions of a thermostat, let’s discuss the application and some of the other thing we need to know when planning thermostat location and applications. 56

57 HEAT PUMP REVERSING VALUE ILLUSTRATION 57

58 . . . . TP-4 TP-2 TP-3 TP-1 SUCTION LINE OUT DOOR COIL INDOOR COIL
COMPRESSOR DISCHARGE 58

59 . . . . HEATING MODE TP-4 TP-2 TP-3 5F MAX TEMP. DIFFERENCE TP-1 TO
ACCUMULATOR TO INDOOR COIL FROM OUTSIDE COIL . . . TP-4 TP-2 TP-3 . FROM COMPRESSOR DISCHARGE LINE 5F MAX TEMP. DIFFERENCE TP-1 HEATING MODE 59

60 . . . . . . . . . . COOLING MODE TP-4 TP-3 TP-2 TP-1 5F MAX TEMP.
TO ACCUMULATOR FROM INDOOR COIL TO OUTDOOR COIL . . . . . . . TP-4 TP-3 TP-2 . . . TP-1 FROM COMPRESSOR DISCHARGE LINE 5F MAX TEMP. DIFFERENCE COOLING MODE 60

61 HEAT PUMP METERING DEVICES
HEATING CYCLE, REFRIGERANT IS METERED TO THE OUTDOOR COIL COOLING CYCLE, REFRIGERANT IS METERED TO THE INDOOR COIL 61

62 HEAT PUMP METERING DEVICES
REFRIGERANT METERED TO COIL WHICH ABSORBS HEAT HEATING CYCLE REFRIGERANT METERED TO OUTDOOR COIL COOLING CYCLE REFRIGERANT METERED TO INDOOR COIL 62

63 METERING DEVICES CAPTUBE FIXED ORFICE TXV 63

64 METERING DEVICES FLOW BYPASSES METERING DEVICE CHECK VALUE OPEN
FLOW IS METERED CHECK VALVE SHUT METERING DEVICE 64

65 The role of the defrost control
To extract heat from the outdoor air, the heat pump must lower it’s outdoor coil temperature below that of the outdoor ambient. Depending on the humidity and temperature, frost may form on the outdoor coil. This frost will insulate the coil from the outdoor air, reducing it’s ability to absorb the heat from the outdoor air. 65

66 HEAT PUMP DEFROST CONTROLS
- CONTROLS THE DEFROST CYCLE IN A HEAT PUMP DURING HEATING OPERATION. - THE DEFROST CONTROL CONTROLS THE FOLLOWING FUNCTIONS: 1 - SWITCH OVER VALVE OR REVERSING VALVE 2 - OUTDOOR FAN MOTOR 3 - ELECTRIC OR GAS AUX. HEAT 4 - INDICATES A FAULT HAS OCCURRED (OPTIONAL) - CONTROL THAT ESTABLISHES THE NEED FOR A DEFROST - BOTH TIMED AND DEMAND CONTROLS ARE USED TODAY - ELECTRO MECHANICAL TIMERS AND PRESSURE SWITCHES USED IN THE PAST 66

67 Heat pump defrost controls
Several types of defrost controls have been used through the years. We will discuss their function and diagnostics of each type. The newer solid state and Demand Defrost controls will be the main focus of our time today. 67

68 As the frost accumulates on the outdoor coil, the systems capacity is reduced.
To remove the frost/ice from the outdoor coil, the system will shift itself into a variation the cooling mode. During a defrost cycle the outdoor fan will stop, leaving the heat in the coil to remove the frost. The type of defrost control system will dictate how much frost/ice is allowed to accumulate prior to initiating a defrost. 68

69 DEFROST CYCLE SYSTEM IN COOLING MODE- -ENERGIZE REVERSING VALVE
DIRECTS HOT GAS TO OUTDOOR COIL TO MELT THE FROST 69

70 DEFROST CONTROLS THE MUCH OLDER EQUIPMENT UTILIZED ELECTRO-MECHANICAL TIME CLOCKS. ELECTRONIC TIMER - TIME & TEMPERATURE DEFROST SOLID STATE - DEMAND DEFROST 70

71 DEFROST CYCLE TEMPERING INDOOR AIR
ELECTRIC HEAT IS TURNED ON TO TEMPER THE AIR DURING DEFROST CYCLE. 71

72 DEFROST CYCLE OUTDOOR FAN OFF ENHANCES DEFROST 72

73 Electro-Mechanical systems
All electro-mechanical systems are a “time/temperature” based control. A predetermined amount of time must pass before a defrost cycle can be initiated. As mentioned earlier, the outdoor conditions have major impact on the amount of defrost needed. These systems are temperature activated as well. 73

74 Large amounts of frost may accumulate before the “Time” has elapsed.
This results in lower seasonal efficiency. The reduced capacity will result with a greater dependence on a secondary heat source. 74

75 ELECTRONIC TIME-TEMPERATURE DEFROST CONTROL
MINUTE COMPRESSOR RUN TIME SELECTION 10 MINUTE TIME OVERRIDE IN DEFROST CYCLE TWO TEST PINS - ADVANCES ELECTRONIC TIMER AND PUTS SYSTEM INTO DEFROST CYCLE FOR TESTING ON BOARD DEFROST RELAYS FOR OUTDOOR FAN, SOV VALVE AND AUXILIARY HEAT DEFROST TERMINATED ON TIME OR TEMPERATURE COMPRESSOR RUN TIME IS KEPT ONLY WHEN COIL THERMOSTAT IS CLOSED 75

76 The defrost thermostat is set to close at 25º.
When the DT is closed, supplying 24 VAC to the D terminal, jumpering the test pins will speed up the internal clock. If you are testing the system, and have a jumper from R to D, remove the jumper as soon as the system shifts into defrost. To prevent excessive refrigerant pressures. 76

77 I recommend one of the shorter time settings, 50 or 70 minutes.
These controls will default to the 90 minute setting if the selector jumper is not connected. Which is how the equipment is shipped. I recommend one of the shorter time settings, 50 or 70 minutes. The water run off from a unit in defrost is pure water, and has never been reported to caused roof damage to date! Trying to catch the water could damage the outdoor coil (if the collected water froze and backed up under the coil). 77

78 TST EDR R R B B X Y O O D T 78

79 TST EDR R R B B X Y O O D T 79

80 TST EDR R R B B X Y O O D T 80

81 TST EDR R R B B X Y O O D T 81

82 TST EDR R R B B X Y O O D T 82

83 TST EDR R R B B X Y O O D T 83

84 TST EDR R R B B X Y O O D T 84

85 There are several versions of these DFC boards
There are several versions of these DFC boards. Many feature the exact same functions, with the only difference being the terminal for the defrost thermostat being labeled “D” or “DT”. TST EDR R R B B X Y O O D T 85

86 There are several versions of these DFC boards
There are several versions of these DFC boards. Many feature the exact same functions, with the only difference being the terminal for the defrost thermostat being labeled “D” or “DT”. TST EDR R R B B X Y O O D T 86

87 There are several versions of these DFC boards
There are several versions of these DFC boards. Many feature the exact same functions, with the only difference being the terminal for the defrost thermostat being labeled “D” or “DT”. TST EDR R R B B X Y O O D T 87

88 There are several versions of these DFC boards
There are several versions of these DFC boards. Many feature the exact same functions, with the only difference being the terminal for the defrost thermostat being labeled “D” or “DT”. TST EDR R R B B X Y O O D T 88

89 There are several versions of these DFC boards
There are several versions of these DFC boards. Many feature the exact same functions, with the only difference being the terminal for the defrost thermostat being labeled “D” or “DT”. TST EDR R R B B X Y O O D T 89

90 90 70 50 TST EDR R R B B X2 Y O O D T DFC CNT1152 OR CNT1642 K2 K1 M1
OD FAN M2 TST EDR R R B B X2 Y O O D T 24V AC 24V COMMON INDOOR THERMOSTAT MS SC CNT1152 may be replaced by CNT 1642 1 DT 90

91 DFC CNT1642 INDOOR THERMOSTAT EDR EDR F G K2 K1 M1 OD FAN M2
TST EDR R R B B X2 Y O O DT T X2 INDOOR THERMOSTAT Y O T SC EDR DT EDR 24V AC V COMMON ECONOMIZER (OPTIONAL) EDC OR LPCO MS F INDOOR THERMOSTAT G COMMON FOR ELECTRIC HEATER TR TR1 91

92 TIMER DEFROST CONTROL 92

93 DEMAND DEFROST CONTROLS
93

94 DEMAND DEFROST FEATURES ADAPTABILITY LEARNING PROCESS
DEFROST ON DEMAND DIAGNOSTICS TIME OVERRIDE SOFT SWITCHOVER 94

95 95

96 DEMAND DEFROST CONTROLS
96

97 HEAT PUMP DEMAND DEFROST CONTROLS
- TRANE DEMAND DEFROST CONTROLS OPERATE IN AN ADAPTIVE PROCESS TO OPTIMIZE THE HEAT PUMP PERFORMANCE. - THE DEMAND DEFROST CONTROL WILL ADAPT TO THE HEAT PUMP IT IS INSTALLED ON AND LEARN ITS OPTIMUM DEFROST CONDITIONS AND STORE THEM IN MEMORY. - THE DEMAND DEFROST CONTROL WILL ADJUST THE TIME BETWEEN DEFROST CYCLES TO MATCH THE WEATHER CONDITIONS. 97

98 HEAT PUMP DEMAND DEFROST CONTROLS
- THE DEMAND DEFROST CONTROL WAS DEVELOPED BY TRANE IN 1984 AND IS PATENTED. - HEAT PUMP SYSTEMS WITH DEMAND DEFROST CONTROLS BENEFIT FROM A 6% HEATING SEASONAL PERFORMANCE FACTOR (HSPF) ADVANTAGE. - THERMISTOR SENSORS SENSE THE OUTDOOR AMBIENT TEMPERATURE AND OUTDOOR COIL TEMPERATURE. - THE DIFFERENCE BETWEEN THE OUTDOOR TEMPERATURE AND THE OUTDOOR COIL TEMPERATURE IS CALLED THE DELTA TEMPERATURE OR JUST DELTA-T. 98

99 The Defrost Cycle is Initiated
As ice builds on the coil, the delta-t of the system increases until it reaches the initiate value, and the control starts the defrost process. The initiate value is not constant, but instead, is a value that the defrost control has learned will provide a fast, thorough defrost at a given outdoor temperature. Low initiate values waste energy by defrosting too often, while high initiate values fail to defrost the coils thoroughly. The control is continually varying the initiate value slightly to learn the best value. It measures the success of each initiate value by measuring the delta-t of the system during the next heating cycle. 99

100 DEFROST IS TERMINATED Once the temperature of the outdoor coil reaches the termination value, the defrost control turns on the outdoor fan. After waiting the soft-switch over time, it changes the switch over valve to the heating mode. This soft-switch over delay time, 12 seconds, gives the outdoor coil time to cool, reducing the refrigerant pressure and reducing the surge that occurs when the switch over valve is switched. If the compressor or “Y” cycles off during defrost, the switchover valve remains energized but the “X2” output will be OFF. If “Y” cycles off during the soft-switchover time, the switchover valve is switched OFF immediately. 100

101 101

102 102

103 103

104 104

105 105

106 106

107 107

108 Demand Defrost Control Operation
Requirements for defrost initialization 1 - The outdoor temperature must be less than 52 F 2 -The coil temperature must be less than 33 F 3 -The Y line must be energized for a least seconds 4 -The delta-T must be greater than the initiate temperature 5 - It must be time for a timed defrost 6 -30 minutes of run time have passed since the unit was first powered up 108

109 Demand Defrost Control Operation
If the unit is placed into a forced defrost by placing the test jumper in the FRC DFT position and Y is energized, none of the above conditions need to be met. Defrost Controls groups 8 thru 21 have a 6 hour forced defrost below 6 degrees F outdoor temperature with a 3 minute timed override. 109

110 Requirements for Defrost Termination
The coil temperature must exceed the terminate value. If the outdoor temperature is greater than 22 F, the terminate value is 47 F. If the outdoor temperature is less than 10 F, the terminate value is 35 F. If the outdoor temperature is between 10 F to 22 F, the terminate value is 25 F plus the outdoor temperature. OR The defrost control has a for 15 minute override time. 110

111 The Test Mode The control may be placed into a test mode by placing the RED jumper wire on the TST pin. This will cause the LED to blink rapidly and the operation of the control will be five times faster. The controller will run normally once the jumper is removed from the TST pin. 111

112 Fault Indications There are three types of faults the demand defrost control can experience. All three faults can cause the defrost control to change from a demand defrost control to a timed defrost control which defrosts the unit every 30 minutes. When the control goes into a timed defrost mode due to a FAULT A or FAULT C, on units that have the F line feature, it alerts the home owner by energizing the F line once every second which flashes a fault light on the thermostat. If the thermostat is switched to the emergency heat position, the F line will be energized, and the defrost control will be cleared of all faults after a few seconds. 112

113 Fault Indications FAULT A is indicated by 2 led flashes per second.
FAULT A is caused by one of two conditions: 1 - During heating the system's delta-T is unusually low. (The capacity of the system is lower than it should be.) 2 - After 12 minutes of operation since the defrost termination, delta-T is greater than the initiate value. After running in a FAULT A condition for 30 minutes, the defrost control will indicate it by flashing the LED. After running 2 hours with this fault, the demand defrost control will then change to a timed defrost operation, and the homeowner will be notified via the F line. 113

114 Fault Indications FAULT A can be cleared by any one of the following operations: 1 - If the control has two normal defrost cycles (If the fault has been present long enough for the Fault light to start Flashing, it will flash until the first normal defrost.) 2 - If power is removed from the defrost control for more than 30 seconds. 3 - If the F line is energized for a few seconds. 114

115 Fault A 115

116 Fault A 116

117 Fault A 117

118 Fault A 118

119 Fault A 119

120 Fault A 120

121 Fault A 121

122 Fault A 122

123 Fault A 123

124 Fault Indications FAULT B is indicated by 3 led flashes per second.
FAULT B is caused by 10 successive failures of the heat pump to terminate on temperature during the defrost cycle. The unit will stop defrosting after 15 minutes due to the override timer. Once a FAULT B occurs, the control will indicate it by flashing the led. After FAULT B occurs 10 times, the control will act as a timer defrost control. 124

125 Fault Indications FAULT B can be cleared by any one of the following operations: 1 - If the control reaches the terminate value during one of the timed defrost cycles. (Since this fault is pretty common in cold climates with high winds, this fault does not alert the home owner via the F line.) 2 - If power is removed from the defrost control for more than 30 seconds. 3 - If the F line is energized for a few seconds. 125

126 Fault Indications FAULT C is indicated by 3 led flashes per second.
FAULT C is caused by 15 successive faults in which the unit has an unusually high delta-T 15 minutes after a defrost termination. (Poor air flow over outdoor coils - they are probably blocked by ice.) 126

127 Fault Indications FAULT C can be cleared by any one of the following operations: 1 - If the unit has a normal delta-T 15 minutes after a defrost. (If the fault has been present long enough for the Fault light to start flashing, it will continue to flash until there is a defrost cycle without a high delta-T fault.) 2 - If power is removed from the defrost control for more than 30 seconds 3 -If the F line is energized for a few seconds 127

128 Fault B or C 128

129 Fault B or C 129

130 Fault B or C 130

131 Fault B or C 131

132 Fault B or C 132

133 Fault B or C 133

134 Fault B or C 134

135 Fault B or C 135

136 Fault B or C 136

137 Fault B or C 137

138 Combination Fault Indications
FAULT A & FAULT B, indicated by 4 led flashes per second, is caused by 60 or more FAULT A's occurring and one or more FAULT B's occurring. FAULT A & FAULT C, indicated by 4 led flashes per second, is caused by 60 or more FAULT A's occurring and one or more FAULT C's occurring. Combination faults will notify the home owner by toggling the F line. Combination faults can be cleared by any one of the following operations: 1 - If the F line is energized for a few seconds 2 - If power is removed from the defrost control for more than 30 seconds 138

139 Power-up Initial Defrost
After the defrost board is powered up, its first defrost cycle will be a timed cycle. On the newer boards, the unit must run during defrosting conditions for 30 minutes while some older boards must run for 45 minutes. Assuming there are no faults, subsequent defrost cycles will be performed on demand. The delay in each case can be reduced to 1/5 this time by placing the red jumper lead on the TST terminal. 139

140 Forcing the Unit to Defrost
Placing the red jumper wire on the FRC DFT pin, the defrost board can be forced to initiate a defrost immediately even if outside temperature conditions are not met. The only requirement is that the compressor is running or the “Y” signal is present. The defrost will be terminated normally when the outdoor coil becomes hot enough. If the jumper is still on the FRC DFT lead upon defrost termination, it will initiate the defrost cycle again. 140

141 F Line Operation Full featured defrost controls (G15-G17 & G19-G20) have an F line to alert the home owner in the event of a fault. On older controls, the F line would continue to flash a fault to the home owner after the fault was gone, but newer boards stop flashing the Fault light after the faults A, B, and C have passed. This will hopefully cut down on nuisance service calls, and still yet alert the home owner if the heat pump fails. 141

142 No Fault Found DON’T REPLACE IT! Look Elsewhere For Cause(s)
If LED blinks, & Sensors ohm out OK, & Forced defrost works. Look Elsewhere For Cause(s) Package Unit Ambient Sensor Bracket Added for better ambient sensing 142

143 ODS-A Thermistor Failures
Cause Field miswire during installation Solution X2 wire color changed from BR/X2 to BK DO NOT REPLACE CONTROL Use RES0118 ODS-A kit Needed ONLY for GE “blue light” thermostat 143

144 Defrost Control Failures
Early defrost controls would sometimes fail to defrost with the LED steady ON or OFF. If power is removed for 1 minute, the board will resume normal operation. After months of research at Trane and the microprocessor manufacturer, the mechanisms for this type of failure were discovered, and the new defrost boards were designed and tested to resist this type failure. Defrost controls manufactured after Jan have this improvement made. 144

145 Defrost Control Failures
The second problem is caused by miswiring. Often, the anticipator lead has been confused with the X2 lead, because the leads were both brown. In current generation outdoor units the “X2” lead is black, so the incidence of field miswiring should go down. 145

146 Temperature Sensors The temperature sensors are temperature dependent resistors encased in a heat-shrunk plastic shroud and sealed from air and moisture by a hot glue adhesive fill. The resistance of the sensor decreases as temperature increases according to a specified curve. See the temperature / resistance curve provided with the service information. It is rare for a temperature sensor to fail, and most that have been replaced in warranty were OK, or they had been damaged by rough handling. 146

147 Temperature Sensors A common problem with sensors is damage inflicted by forcing ohmmeter probes into their connectors. This permanently bends the contact causing an intermittent connection. On some package units, the sensor leads have been pinched by the access panel. Checking the sensor resistance to ground will detect this problem. 147

148 Check Out Procedure The following tests are to be performed to check for proper operation after installation of the demand defrost control. Step 1: Apply power to the system and operate in heating mode. The switchover valve should be off (heating mode), and the outdoor fan should be on. Step 2: Check to be sure the led on the defrost board is blinking once every second and the fault light on the thermostat is off. Step3: Force the system to defrost by placing the red jumper wire on the FRC DFT pin. 148

149 Check Out Procedure As the unit goes through the defrost process, the switchover valve should be energized, the auxiliary heat should be on and the outdoor fan motor should be off. Step 4: Monitor the system to be sure it stops defrost within 15 minutes. Step 5: At the end of the defrost cycle, the outdoor fan should come on, and after a 12 second delay, the unit will switch back to the heating mode. 149

150 Check Out Procedure Step 6: If the board has the fault light feature (G15-G17& G19-G20), test this feature by placing the red jumper wire on the FRC FLT pin for a few seconds then return the red jumper wire to the NORM pin. This should cause the led on the defrost board to blink four times a second, and the indoor fault indicator on the thermostat should be blinking once a second. Step 7: Switch the indoor thermostat to the emergency heating position for at least 30 seconds and then back to the heat pumps position. The indoor fault indicator should stop blinking and the LED should blink once a second indicating that everything is normal. 150

151 Helpful Hints in Case of Difficulty
Led fails to blink on the defrost board If the led is off, check between R and B to be sure 24 volts is present. Remove power for one minute and re-apply power. Check to see if the LED starts flashing. 151

152 Helpful Hints in Case of Difficulty
LED flashes, but the unit fails the forced defrost test. 1. Be sure the red jumper wire was returned to the NORM pin. 2. Make sure the thermostat is calling for heating (24 V on Y) 3. Verify that the sensors are connected and mounted in the right places 4. Check the electrical connections to the defrost board (24V on O while defrosting) 5. There is a 1 minute minimum time in defrost under normal operation. If defrost is forced there is no minimum time in defrost. 152

153 Helpful Hints in Case of Difficulty
1- The indoor fault indicator goes on and then goes off. During extreme weather conditions, the unit may have difficulty defrosting. This will cause a fault and alert the owner, but when the weather is more temperate, the fault will clear and the indicator will stop blinking. 2 - The outdoor sensor (ODS) is burnt on the defrost board. Check control wiring “T” and “X2” . On the newer units the X2 lead is black and this is not as likely to happen. 153

154 Demand Defrost Control Problems Excessive Ice Built-up on OD Coil
Low refrigerant charge Defrost Control will not Initiate A. No 24 VAC between R&B at defrost control B. No 24 VAC between B&Y at defrost control with system running C. Verify correct sensor location, mounting & their resistance D. Verify ambient sensor is connected to AMB position on defrost control E. Verify coil sensor is connected to coil position on defrost control 154

155 Demand Defrost Control Problems Excessive Ice Built-up on OD Coil
SOV Inoperative A. Stuck in heating mode B. Open switchover valve (SOV) coil C. Defective defrost control Defrost control contacts to OD fan fail to open during defrost cycle 155

156 Demand Defrost Control Problems Excessive Ice Built-up on OD Coil
Defrost control terminates, but does not remove ice A. Windy conditions B. Outdoor unit located under eaves C. Lack of proper drainage D. Night setback operation 156

157 Ice Build Up on Lower Part of Outdoor Coil
Low refrigerant charge Coil sensor connected to wrong pass of outdoor coil, or poor contact Leaking check valve (outdoor unit) Distributor tube restricted One pass of OD coil restricted Lack of proper drainage 157

158 Defrost Initiates, but Terminates Only on a Time Override
Low refrigerant charge Outdoor fan on during defrost Windy conditions Night setback operation Unit location Coil sensor in contract with ice Coil sensor circuit open or reading very high resistance. 158

159 Defrost Cycle Initiates, but Will Not Terminate
Defrost Control Switch-over valve stuck in cooling mode 159

160 Unit Goes Into Defrost In Cooling Mode
Defective Sensors Defective Defrost Control 160

161 Control Terminates Defrost Before Frost Is Gone
Coil sensor mounted in wrong location or has incorrect resistance reading Refrigerant overcharge 161

162 Defrost Initiates About Every 15 Minutes
Coil sensor Ambient sensor Defrost control 162

163 Defrost Initiates About Every 30 Minutes
Defrost Initiates About Every 30 Minutes. Fault Light on Indoor Thermostat Will Be Flashing If Wired Coil sensor Ambient sensor Weather conditions Night setback operation Outdoor fan on during defrost System refrigerant charge SOV operation 163

164 Two-Compressor Controllers
Tyler Version For V.S. OD Fan Motor Cooling model 21C150624G02, CNT2275 Heatpump model 21C150625G02, CNT2276 164

165 Two-Compressor Controllers
Ft. Smith Version for PSC Fan Motor Cooling model 21C150624G01, CNT1858 Heatpump model 21C150625G01, CNT1859 165

166 Heat Pump Control 166

167 EFFICIENCY EER COP SEER HSPF 167

168 EER = 8.9 BTU/WATT BTU’S OUT 39,000 BTU/HR. POWER IN 4380 WATTS/HR.
168

169 COP BTU’S OUT ,000 BTU/HR BTU’S WE WATTS/HR X BTU/WATT PAY FOR 2.6 = 169

170 COP FOR HEAT PUMP AND RESISTANCE HEAT
4.0 3.0 HEAT PUMP 2.0 HEATING COP RESISTANCE HEAT 1.0 -20 -10 10 20 30 40 50 60 OUTDOOR TEMPERATURE 170

171 HSPF HEATING SEASONAL PERFORMANCE FACTOR
TOTAL HEATING OUTPUT OF A HEAT PUMP DURING ITS NORMAL ANNUAL USAGE PERIOD FOR HEATING DIVIDED BY THE TOTAL ELECTRIC POWER INPUT IN WATT-HOURS DURING THE SAME PERIOD 171

172 SEER SEASONAL ENERGY EFFICIENCY RATIO
TOTAL COOLING OF A CENTRAL UNITARY AIR CONDITIONER OR UNITARY HEAT PUMP IN BTU’S DURING ITS NORMAL ANNUAL USAGE PERIOD FOR COOLING DIVIDED BY, THE TOTAL ELECTRIC POWER INPUT IN WATT-HOURS DURING THE SAME PERIOD 172

173 WHEN CAPACITY DROPS EER&COP - CAPACITY - SUCTION - TEMPERATURE
PRESSURE OUTDOOR TEMPERATURE 173

174 WHAT CAUSES CAPACITY TO DROP
GAS DENSITY DECREASES SHORTER EFFECTIVE STROKE DECREASED FLOW RATE + = 174

175 CAPACITY VS. HEAT LOSS HEAT LOSS UNIT CAPACITY CAPACITY TEMPERATURE
SUPPLEMENTAL HEAT NEEDED TEMPERATURE 175

176 ELECTRIC HEAT SUPPLEMENTAL HEAT EMERGENCY HEAT AUXILIARY HEAT
RESERVE HEAT 176

177 THERMAL BALANCE POINT HEATING CAPACITY HEAT LOSS = HEAT PUMP 177

178 CAPACITY VS. HEAT LOSS BTU/HR HEAT LOSS UNIT CAPACITY 45,000 21,000
10F 50F OUTDOOR TEMPERATURE 178

179 BALANCE POINT BALANCE POINT BTU/HR HEAT LOSS UNIT CAPACITY 34,500
32.5F 65F OUTDOOR TEMPERATURE 179

180 DESIGN POINT BTU/HR HEAT LOSS 57,500 UNIT CAPACITY 21,000 DESIGN POINT
NEED 36,500 BTU/HR ADDITIONAL 21,000 DESIGN POINT 10F OUTDOOR TEMPERATURE 180

181 EMERGENCY HEAT = 16.8 KW BTU/HR HEAT LOSS 57,500 X 1.00 57,500 BTU/HR
UNIT CAPACITY 57,500 BTU/HR 3413 BTU/KW = 16.8 KW 10F OUTDOOR TEMPERATURE 181

182 TOTAL CAPACITY WITH 17 KW HEATER PACKAGE
3RD STAGE 2ND STAGE 1ST STAGE 19,340 BTU/HR UNIT CAPACITY 19,340 BTU/HR 19,340 BTU/HR (5.66KW) 182

183 BALANCE POINT 1 ST STAGE ELECTRIC HEAT
HEAT LOSS 1ST STAGE UNIT CAPACITY 22.5F OUTDOOR TEMPERATURE 183

184 BALANCE POINT 2ND STAGE ELECTRIC HEAT
HEAT LOSS 1ST STAGE UNIT CAPACITY 13F OUTDOOR TEMPERATURE 184

185 BALANCE POINT 3RD STAGE ELECTRIC HEAT
BTU/HR BALANCE POINT 3RD STAGE 2ND STAGE HEAT LOSS 1ST STAGE UNIT CAPACITY DESIGN POINT 4F 10F OUTDOOR TEMPERATURE 185

186 Heat pump with heat strips
This application has a 17KW heat strip. You will see that W2 heat strip is brought on during defrost. The W1 and W3 heat strips are controlled by outdoor thermostats. Only bringing them on as the outdoor temperature drops. 186

187 TO LINE VOLTAGE SUPPLY BK/BL BR/RD TDL SUMP HTR PURPLE/WH PURPLE/WH
BLACK BLACK CS MS CSR CSR RD BR BK/BL OR BK/BL S R OR CPR IOL CR RD RD BR/RD LO HI RED BROWN FAN MTR BL/WH CF OFT-B OFT-A PURPLE BLACK BK/RD CBS YL YL BK BK RD ODS-B Y1 R B B O O Y Y X2 F 187

188 YL YL BK BK YL X BK HEATER CONTROLS X BK X X BK X X BK X BR BL RD 188
R B B O O Y Y X2 F RD/WH RD BL F SM-1 OR YL BK F OR O HEAT OFF COOL O O BLACK HA CA Y YL Y Y WS X BK HEATER CONTROLS RHS-1 TS W3 X2 X BK X W2 X2 X BK X X BK X W1 J SM-2 COOL AUTO ON G G HEAT FAN FAN CONTROL BD T RHS-2 ODS-A T ODA BR T T TSH W RD U B BL BL B B R RD R R TO POWER SUPPLY PER LOCAL CODES TYPICAL AIR HANDLER TYPICAL MANUAL CHANGE OVER THERMOSTAT 188

189 EMERGENCY HEAT RELAY PACKAGE
MAINTAINS COMFORT IF HEAT PUMP FAILS BY 1 LOCKING OUT COMPRESSOR 2 BYPASSING OUTDOOR THERMOSTAT 3 BRINGING ON FULL STRIP HEAT 189

190 SQUEEZING OUT OPERATIONG $
DECREASE BALANCE POINT OVERSIZE HEAT PUMP UPGRADE BUILDING INS. & GLAZING TURN DOWN THE THERMOSTAT DUAL - ALTERNATIVE HEATING SYSTEM 2 - STAGE HEAT PUMP 190

191 LOCATING THE UNIT AIR CONSIDERATIONS WATER DRAINAGE
AVOID RECIRCULATION CUT OFF PREVAILING WIND WATER DRAINAGE ALLOW CLEARANCE FOR WATER DRAIN OFF SNOW CONSIDERATIONS AVOID SNOW DRIFTS RAISE UNIT IN HEAVY SNOW AREAS 191

192 LOAD CALCULATION AIR FLOW CHARGING CAPACITY 192

193 DUAL FUEL 193

194 HEATING “ON” CYCLE FOSSIL FUEL HEAT PUMP TEMP TIME 194

195 DUAL FUEL SYSTEMS DEPENDS ON THE COST OF ELECTRICITY AND PRICE OF THE FOSSIL FUEL LESS EXPENSIVE TO HEAT COMPRESSION-CYCLE EQUIPMENT WHEN THE OUTDOOR TEMPERATURE IS MILD TO MODERATELY COLD MORE ECONOMICAL TO HEAT WITH FOSSIL FUEL WHEN THE OUTDOOR TEMPERATURE IS VERY COLD REDUCES DEMAND FOR POWER DURING PERIODS OF COLD WEATHER 195

196 ECONOMIC BALANCE POINT
OUTDOOR TEMPERATURE ASSOCIATED WITH EQUAL OPERATING COSTS 196

197 ADD-ON HEAT PUMP KIT TYPLUS103A
SEQUENCE OF HEATING OPERATION NON-RESTRICTIVE MODE FIRST STAGE HEAT, HEAT PUMP (ONLY) OPERATES IN HEATING, IF HEAT PUMP CANNOT HANDLE THE LOAD , WHEN THE TEMPERATURE IN ROOM DROPS APPROX. 1-1/2F, FURTHER, SECOND STAGE HEAT IS CALLED FOR. SECOND STAGE TURNS THE HEAT PUMP OFF AND BRINGS THE FURNACE ON. FURNACE WILL SATISFY SECOND STAGE ONLY. FIRST STAGE IF CALLING WILL OPERATE AFTER 45 SEC. DELAY THERMOSTAT EMERGENCY HEAT POSITION OPERATES FURNACE ONLY 197

198 ADD-ON HEAT PUMP KIT TYPLUS103A
SEQUENCE OF HEATING OPERATION RESTRICTIVE MODE - ( REQUIRES TAYSTAT250A ) O.D.T. CHANGEOVER AT OR ABOVE ECONOMIC BALANCE POINT TEMPERATURES ABOVE O.D.T.,HEAT PUMP ONLY,WHEN CALLED BY FIRST STAGE STAT. TEMPERATURES BELOW O.D.T.,FIRST STAGE STAT. GOES TO THE FURNACE AND HEAT PUMP IS CUT OFF EMERGENCY HEAT POSITION CONVERTS SYSTEM TO FURNACE ONLY OPERATION 198

199 “A” COIL UPFLOW APPLICATION
AIR FLOW SUPPLY DUCT CLASS 2 LOW VOLTAGE WIRING TO SYSTEM CONTROLLER COIL ENCLOSURE BONNET THERMOSTAT “A” COIL FRONT COIL BAFFLE NOTE: 1. MOUNT BONNET THERMOSTAT THROUGH FRONT COIL BAFFLE AT THE HIGHEST PRACTICAL POINT INSIDE THE ‘A’ COIL SO THE SENSING ELEMENT DOES NOT TOUCH EITHER SLAB OF COIL OR INTERFERE WITH TUBING. NOTE 1 UPFLOW FURNACE 199

200 ROOM THERMOSTAT T O R W Y B X2 G FIELD WIRING DIAGRAM FOR SPLIT HEAT PUMP SYSTEM WITH TAYPLUS103A CONTROL IN FURNACE (UNRESTRICTED MODE) INTER-COMPONENT WIRING 24 V FACTORY LINE V. WIRING 24 V FIELD FIELD INSTALLED FACTORY WIRING W Y X G3 K1-3 K1-2 G1 K TDR HEAT PUMP O.D. SECTION BR T OR O YL Y RD R BL B TDR - 1 Y2 K1-1 FURNACE BR/X2 OR BK X2 X2 G W1 W2 R B Y BT TAYPLUS103A Y1 B W1 LEGEND TDR - TIME DELAY RELAY MODEL RLY1664 K RELAY MODEL RLY1663 BT BONNET THERMOSTAT MODEL THT1248 TO POWER SUPPLY PER LOCAL CODES TO POWER SUPPLY PER LOCAL CODES 3 PH. ONLY 3 PH. ONLY 200

201 ROOM THERMOSTAT T O R W Y B X2 G FIELD WIRING DIAGRAM FOR SPLIT HEAT PUMP SYSTEM WITH TAYPLUS103A CONTROL IN FURNACE (RESTRICTED MODE) INTER-COMPONENT WIRING 24 V FACTORY LINE V. WIRING 24 V FIELD FIELD INSTALLED FACTORY WIRING W Y X G3 K1-3 K1-2 G1 K TDR HEAT PUMP O.D. SECTION BR T OR O YL Y RD R BL B TDR - 1 Y2 K1-1 FURNACE BR/X2 OR BK X2 X2 G W1 W2 R B Y BT ODT TAYPLUS103A Y1 B W1 LEGEND TDR - TIME DELAY RELAY MODEL RLY1664 K RELAY MODEL RLY1663 BT BONNET THERMOSTAT MODEL THT1248 TO POWER SUPPLY PER LOCAL CODES TO POWER SUPPLY PER LOCAL CODES 3 PH. ONLY 3 PH. ONLY 201

202 Component failures Component’s that fail after 30 days of operation, but prematurely. A 2 year old compressor or fan motor. If a component last for 100 hours of operation, but not 10,000 hours, odds are it is a symptom of another yet undiagnosed problem! 202

203 Mechanical problems that cause electrical failures
Failure of start components or compressor? Compressor starting with liquid present! Overcharged unit. Crankcase heater circuit failure. Cycle rate too short, superheat never stabilizing. Low supply voltage is the least common, and most often assumed. 203

204 Things we need to get better at
Gathering information from the consumer. Looking beyond the failure in front of us, why did it fail. Shit does not just happen! Charging, letting the system run long enough to stabilize. Taking subcooling and superheat. Remembering that over 50% of the electronic controls replaced didn’t need to be replaced! 204

205 The MOST important thing to remember
Trane technicians are proven to be the best! 205

206 The End Thank you 206


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