GMV9, and GCV9 TUBULAR GAS FURNACE.

GMV9, and GCV9 TUBULAR GAS FURNACE

Heating Capacity Model Hi-Fire Lo-Fire GMV90703B 70 66.9 48 46.4
(thousand btu/h) Lo-Fire Input Output GMV90703B 70 66.9 48 46.4 GMV90904C 90 88.8 64 61.7 GMV91155D 115 111.1 80 77.4 GCV90704C 65.3 45 GCV90905D 86.5 60.1

Cooling Capacity Model Hi-Stage Cooling GMV90703B GMV90904C GMV91155D
1.5 2.0 2.5 3.0 GMV90904C 3.5 4.0 GMV91155D 5.0 GCV90704C GCV90905D Supports a wide range of Cooling requirements

VENT TERMINATION CLEARANCES

STANDARD CONNECTIONS

VERTICAL TERMINATIONS (DUAL PIPE)

STANDARD HORIZONTAL TERMINATIONS

ALTERNATE HORIZONTAL VENT TERMINATIONS

TERMINATIONS ABOVE ANTICAPATED SNOW LEVEL

HORIZONTAL CONNECTIONS (RIGHT SIDE DOWN)

HORIZONTAL CONNECTIONS (LEFT SIDE DOWN)

TUBE INSTALLATIONS / GREEN HOSES

Thermostat Options Single-stage heating/Single-stage cooling
Two-stage heating/Single-stage cooling Two-stage heating/Two-stage cooling Fossil fuel application (Kit required) Three-stage heat pump thermostat required

THEMOSTAT WIRING

Thermostat wiring

Pressure Switch Check New There are 3 Pressure Switches
Hi and Low Fire are grouped together The Pressure Switch by itself is the Cover Switch All Pressure Switches are open Switches

GAS PRESSURE ADJUSTMENTS

MANIFOLD GAS PRESSURE

Induced-Draft Blower Jackel 2-speed blower assembly
Motor suspended on four motor mounts for vibration-free operation Factory-installed rubber discharge makes venting a snap Alternate flue/vent through RIGHT side with GMV9 and LEFT side for GCV9 Air flow

Electronic Controls

Integrated Control Board
16-pin connector (ECM Motor) 24V Terminal block D-hum,W2,W1,R,G,B,Y,YLO,O 3 amp Fuse Yellow Dehumidification LED Green CFM LED 12-pin connector (Diagnostics) ICM Microprocessor Red Diagnostic LED 5-pin connector (inducer/ignitor) Hot Connections (Line, XFMR, EAC, HUM) Neutral Connections (Line, XFMR, EAC, HUM)

Single-stage Thermostat?
Set dip switch #3 Off = 5 minutes On = 10 minutes Then Move this jumper to the left Easily converted from 2-stage to 1-stage T-stat operation

Accessories Supported
Dehumidistat (Yellow LED indicator) 115-volt Humidifier (1 120 volts) 115-volt EAC (1 120 volts) 24-volt Humidifier

CFM LIGHT Green Light On The Bottom Right Side Of The Board
1 Blink For Every 100 CFM

Start-Up Procedure 1 Connect 115 power, proper grounding and polarity
2 Continuous flash indicates reverse polarity 3 Follow I&O procedure for natural or LP gas 4 Refer to Spec Sheet for correct cfm/temp rise 5 Determine correct system cooling cfm 6 Green cfm LED flashes once per 100 cfm 7 Adjust blower speed using ICM dip switches 8 Turn off power for 10 sec after each adjustment 9 Verify new cfm with green LED 10 Select cooling speed with dips 1,2,3, & 4 11 Select desired ramp profile with dip 5 & 6 12 Select heating speed with dip 7 & 8

Adjusting the Proper CFM Setting

Select Cooling Speed Cool Tap Adjust Tap
SW1 SW2 Tap SW3 SW4 Adjust Off A Norm On B Pos C Neg D Test Find proper cooling tap in PDB based on ~400 cfm/ton

Select Auto-Comfort Profile
SW5 SW6 Tap Off A On B C D Select Profile D for Auto-Comfort Mode

Select Heating Speed Heat Tap
SW7 SW8 Tap Off A On B C D Select slowest heating speed possible while maintaining temp rise for minimum energy usage

Select Heat-Off Delay Heat-Off Delays SW1 SW2 Sec. On 60 Off 90 120
150

SEQUENCE OF OPERATIONS COOLING
RY&G Are Energized (Hi-Cooling) Call for Cooling Condenser Turns On and the Blower Ramps Up to Cooling Speed, EAC Terminal are Now Energized System Runs Till T-Stat is Satisfied Outdoor Unit Turns Off and Blower Continues for 45 Seconds, Blower is Ramped Down and EAC Terminals are Turned Off In Constant Fan Mode, Fan Continues at 56% of Cooling Speed

SEQUENCE OF OPERATION Heating
R & W1 (Low Fire) Call For Heat Inducer Draft Motor Starts Pre-Purge on Hi Fire (10 seconds), Humidifer Terminals are energize Inducer Draft Motor drops to Lo, Low Fire Pressure Switch Closes Igniter warms up 5 Min. to 9 Seconds opens on Max. Gas Valve opens on Low Fire ,…… Flame Sensor Detects Flame If Call for Hi-Heat , Inducer Draft Motor and Gas Valve Jumps up to Hi-Fire Blower Delay Starts Blower To Ramp Up for 30 Seconds

SEQUENCE OF OPERATIONS Heating
8. EAC Terminal Energized Unit is Now Heating 9. If T-Stat Call for Low Fire, Inducer Draft Motor and Gas Valve Jump to Low Fire till T-Stat is Satisfied 10. Call for Heat Has Been Satisfied, Gas Valve Shuts Off and Inducer Draft Motor Does a Pre-Purge (15 Seconds) 11. Selected Heat-Off Delay 90, 120,150, 180 Seconds and Then the Blower Ramps Down

Troubleshooting

Field Returns Handling Boards by Edges or Use ESD Ground Strap
No Repeated Control Change-out Moisture Control in Board Area Return Tag Information Boxes or Bags for Field Returns

Understanding ECM Motors
ECM is an acronym for “Electronically Communitated Motor” Later versions were called “ICM” or “ICM2” the acronym for ‘Integrated Control Motor” These acronyms are based more in marketing than in reality. By that I mean that it sounds really cool from a sale perspective, But confusing for the technician. Because--- in reality, it is simply a three phase motor with an end bell assembly that controls the frequency of the three phase power to achieve the variable speed functions. What does ECM mean? Electrically Commutated Motor

How Does the ECM Work? HVAC SYSTEM CONTROL
POWER CONDITIONING AC TO DC CONVERTER INVERTER MOTOR CONTROL AC POWER HVAC SYSTEM CONTROL INPUTS 24VAC Compressor On/Hi/Lo Fan On Rev Valve Aux/Emerg Heat Capacity Select Available Outputs CFM ECM This is the standard block diagram of an ECM motor. The AC power is the line voltage into the end bell. The power goes through some electrical filters. We don’t want any spikes or transient surges causing problems. We run it through a full wave rectifier to convert it to DC power. The motor control takes over here; and based upon the signal inputs, the motor control send a signals to the power inverter. The power inverter converts the DC power into three phase power at the frequency and wattage output determined by the motor control. One thing they never show you on the block diagrams is…How does the motor control know the motor is actually running? Simple, there is a pick up on the power inverter output that senses the motor watts and RPM. The motor control knows what the drive signal output is (What did it tell the motor to do) and it knows what the motor is actually doing. By correlating this information, the control can determine if it needs to apply more power or increase the RPM to maintain a given workload output. (in this case, CFM)

How Does the ECM Sense Static Pressure?
Input Power vs. RPM 550 500 450 400 P = kN^3 1000 RPM 350 1/2 N = 1/8 P 280 Watts 300 1/8 X 280W = 35W Input Power (watts) How Does the ECM Sense Static Pressure? This is a little oversimplified, but for any given application, there is a relationship between Torque, RPM, CFM, and Watts. This relationship between speed and power is a little different for each application. Which is why there are so many different ECM end bell assemblies. For example; the internal resistance in a package unit, is much different than the internal resistance in a BBC blower. This internal resistance is what creates the relationship between the RPM, CFM and Watts. Amana (and all other manufactures who use ECM motors) will set up an ECM motor in a given application (like a BBC blower for example) in a wind tunnel and plot a chart of curve similar to this one which defines the relationship between the RPM, CFM and Watts. This curve is then programmed into the ECM End bell assembly. As the ECM motor ramps up, it will increase the motor RPMs until the RPM/Watts falls within the programmed curve. The motor then levels off at that RPM/Watts setting. In addition to this we set a RPM limit on the end bell. If the motor is install in an application where the total allowable static is exceeded, the motor RPMs will continue to increase until the rev limit is hit, then the motor will back off, then rev up again. This creates a puffing sound or effect. Why is there a Rev limiter on ECM motors? The rev limiter is not set to protect the motor. In fact the motor is capable of RPMs far greater than what Amana sets. We set the rev limiter to protect the blower wheels. All blower wheels have what is called a natural frequency. At a certain RPM, which is different for each size blower wheel, the blower wheel blades responds to the vibrations caused by the RPMS and will literally come apart. With ECM motors, we can program the motors to avoid these RPM ranges. 250 200 150 500 RPM 35 Watts 100 50 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 RPM

ECM Advantages Efficiency gain
Lower static pressure yields greater efficiency gain

Static-independent Airflow
ECM Advantages Static-independent Airflow Set the airflow and go! 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 408W 745W System airflow is starved insufficient cooling/heating liquid refrigerant return to condenser Over blowing the system poor moisture removal high power consumption moisture in the duct work PRESSURE Typical profile with a PSC motor Airflow (CFM)

How Does the ECM Work? The End Bell defines motor characteristics.
Motor Connector The End Bell defines motor characteristics. Only 3 motor sections ½, ¾, or 1 hp. The motor is really a three phase motor with a permanent magnet rotor. Motor Section The End Bell defines motor characteristics; The BBC60, PHB60C, PGD60, and the GUVA115 all have the same motor section while they are each in very different applications and even different operating voltages. Only the programming of the End Bell Assembly is different. Only 3 motor sections ½, ¾, or 1 hp. Within Amana, we only use ½, ¾, or 1 hp regardless of the voltage or application. G E does offer other ECM motor for different applications, but Amana does not use them at this time. For example, in the future, you may see a smaller fractional horse power ECM motor in a condenser fan application. But not at this time. THE MOTOR The motor is really a three phase motor with a permanent magnet rotor. You may be asking your self “Why are we doing this?” First, the permanent magnet rotor allows for a near zero rotor loss, greatly increasing the efficiency. Secondly, the ECM end bell controls the power frequency to control the motor RPM. By using three phase field windings, we can program the motor for maximum RPM, Rotation, and other design behavior. If this is such a great ideal, why don’t we use permanent magnet rotors in standard three phase motors? Answer --- We need the slippage of a wound rotor in three phase motors. Zero rotor loss would create some real torque coupling issues without the ramp up features of the ECM motors. End Bell Assembly

Service and Installation Basics

Power Connectors Low Voltage High Voltage Connectors are keyed
Don’t force in the wrong orientation Pull on the plug, NOT the cable DO NOT pull power cable out during operation – Arching could occur When we begin to look at troubleshooting the motor electronically, we need to observe certain precautions. Here we show the High and Low voltage connections. Make sure the motor is off before unplugging the power cable to prevent arching. Connectors are keyed: Believe it or not field failures have been received where someone has tried to force the connectors in upside down. Low Voltage 16 PIN CONNECTOR High Voltage 5 PIN CONNECTOR

Power Connectors Continued Operating Voltages Application Note
5 Pin Power Connector 120 VAC uses a jumper (red wire) Control operates at 240 VAC Jumper enables voltage doubler Do not apply 240 VAC with jumper installed as motor and control will fail. 240 VAC input does not use a JUMPER 16 Pin Signal Connector 120 VAC Power Connector: 120 V becomes 240 V inside the motor due to the voltage doubler 240 VAC Power Connector: Used for 240 VAC input applications If 240 VAC input is used with a jumper, the result will be 480 VAC in the motor and the control will be destroyed. This is VERY DANGEROUS – Never use a jumper with 240! Signal Cable: Controls motor output Pulse Width Modulation (PWM) or 24 VAC Thermostat Mode or Digital Serial Interface (DSI) Operating Voltages Application Note

Troubleshooting ECM Motors
What is Normal? It is normal for the blower to rock back and forth at start up. It is normal for the shaft to feel rough or bumpy when turned. Don’t judge the motor by the RPM or ramp up sequence. Many people ask… Why does the ECM motor rock back and forth on start up? The ECM ramp up program starts the motor off slow and with very low torque, as a result, sometimes the rotor will slip one or two cycles. We do this to make the motor more efficient. Remember the motor is basically a three phase motor and we could program the motor to launch like a dragster, but that would greatly reduce the motor efficiency, and put more stress on the blower wheel. A standard 3 phase motor draws from 270 to 400% of running load amps at start up. This is one of the behaviors of electric motors that really hurts their efficiency. By starting up the motors with this ramp up program, we are saving a lot of energy. Why does the shaft to feel rough or bumpy when turned? Remember, the motor rotor is a permanent magnet rotor. As you turn it, the magnets create a electrical current in the field windings. If this current is not allowed to bleed off, It creates a counter magnetic field, or resistance. It is true that some failures of the ECM power head can cause the motor to be very easy or very hard to turn. But, what you don’t want to do… Is to judge a motor failure by how hard it is to turn the shaft.

Don’t judge the motor by the RPM or ramp up sequence. off All slew rates are controlled Profile A Profile B Profile C on Don’t judge the motor by the RPM or ramp up sequence. The programming capabilities of the ECM end bell allow for up to 16 steps or 16 different CFM levels before the motor reaches the final CFM setting. At Amana we don’t use all 16 steps but the point is, each different motor has a programmed start up sequence designed to maximize the system efficiency. Don’t replace the motor just because you think the RPM is low or high. There are too many factors which influence motor RPM. Pre-run Short run Full capacity Off Delay Time: min, 16 steps Level: % 16 steps

The # 1 failure of ECM motors…………… No Fault Found ! (80%) The # 2 failure of ECM Motors …………… Moisture. (16%) All other failures (4%). Remember earlier we talked about ECM motors having longer life? Starting today We can easily eliminate 96% of all ECM replacements. If we can address these two items alone, we will make the ECM motors more reliable than the standard PSC motors.

Always make sure the motor is oriented such that the connectors are on the bottom Make sure the electrical connections form a drip loop to prevent any moisture from running down the harness and into the end bell assembly. A blower wheel loose on the motor shaft can cause the blower to vibrate, excessive noise, and may cause motor malfunction. Moisture being the number one cause of failure. We can’t stress strongly enough, the need to address this moisture issue. Always make sure the motor is oriented such that the connectors are on the bottom Make sure the electrical connections form a drip loop to prevent any moisture from running down the harness and into the end bell assembly. How many of you are saying OK I will buy into the noise and vibration issue, but how can a loose blower wheel cause a motor malfunction? This is how it works. As the motor starts to ramp up, the blower wheel shifts. This shift causes a spike or wave in the watts to the motor. The ECM see this spike and doesn’t know what to do about it and shuts down. This doesn’t happen every time you have a loose blower wheel, but it does happen sometimes. You just want to be aware that it can happen. Drip Loop Electrical Connections on Bottom

There are some ECM motor testers on the market today. There are some good ECM motor Testers on the market, but do you really need one? Not if you understand the ECM motor. Don’t get me wrong. I would like to have the one on the right, It has a lot of neat functions, looks cool, and Amana will have one similar to it… someday. The one on the left will apply power to the pin for a thermostat input programmed motor. It does not provide PWM signal and is really not adequate for testing BBC motors which use the PWM technology. But you can do just as well with an understanding of the ECM motor and a simple VOM meter. The key is to understand how the ECM works.

GE TECMateXLTM Service Tool Buy it on www.thedealertoolbox.com.
Analyzes the GE ECM independent of the HVAC system Can test the basic settings: Fan-only, Heating, Cooling and Dehumidification Will detect and isolate motor failures from HVAC system failures Accurate and quick diagnosis means better customer satisfaction Don’t even have to take the motor out of the blower Follow instructions in the Home Comfort Guide. Buy it on Click on the TECMateXLTM Service Tool link under the Service Tools tab.

GE TECMateXLTM Service Tool
How to Use the GE TECMateXLTM The table on the back of the TECMateXL shows expected results for various settings. 1. CAUTION: Disconnect AC power from the system being serviced and wait 5 minutes before opening motor. Remove the 16-pin connector from the motor, and connect the 16-pin connector from the TECMateXL to the motor. Do not disconnect the 5-pin AC power connector from the motor (see Figure 1). Connect the two alligator clips from the TECMateXL to a 24VAC source. Place all switches on the TECMateXL in the off position. Figure 1 24VAC 120V or 240V AC Power TECMate ECM Motor ECM motors are used in one of two modes: Thermostat Mode or Variable Speed Mode. Thermostat Mode is controlled by a 24VAC signal usually from a thermostat. Variable Speed Mode is controlled by a Pulse Width Modulating (PWM) signal. In either mode, the TECMateXL is capable of identifying a motor control failure versus other HVAC system controller or wiring failures.

GE TECMateXLTM Service Tool Continued
5. Reconnect AC power to the system. The TECMateXL power led should illuminate when connected properly to 24VAC. 6. Place the correct switches in the ON position and observe the motor for 15 seconds. (Refer to the Table on back of the TECMateXL for switch selections of the various test mode settings). If the motor starts with the TECMateXL, then the system malfunction is not caused by an ECM motor/control. Refer to the Troubleshooting Guide on page 2 for help in diagnosing the system malfunction. 8. When finished testing a mode, place all switches in the off position and wait for the motor to completely stop before testing the next switch selections. (Based on the OEM program, sometimes the motor will not shut-off immediately after a setting has been tested; this is normal.) 9. If the motor does not start with the TECMateXL, then proceed to replace the electronic control module in accordance with the instructions on page 4. Note: Before replacing the electronic control module, you must test the motor module to ensure it is not also damaged. Procedures for testing the motor module are included in “Replacing the ECM Control Module” instructions on page 4. Note: Do not operate motor without blower wheel attached. Such operation will cause the motor to oscillate up and down. These steps for using the TECMate can be found in the GE ECMTM Home Comfort Guide. The truth table shown is located on the back side of the TECMate, and it displays the different switch combinations required to test the different modes.

Ultimate Comfort Setup Guidelines
GE provides a wide array of programming options in the ECM motor that make it easier to optimize homeowner comfort. Basic Steps to Ultimate Comfort 1. Perform a room-by-room load calculation using ACCA Manual J. 2. Select the proper size equipment so it delivers the expected comfort and efficiency. 3. Keep static pressure to a minimum. Design ductwork for minimum static and maximum comfort. Follow ACCA Manual D. Look for and recommend ductwork improvements where necessary. 4. Recommend high efficiency, low pressure drop filters and recommend keeping the filters clean. 5. Select the proper cooling airflow to match the system tonnage using the identified switches or jumpers on the system control board. 6. If needed make airflow adjustments to further optimize comfort using the trim selection on the system control board. 7. Finally, install a humidistat or select the airflow ramp profile that best removes humidity or improves efficiency for customized comfort.

Replacing the ECM Control Module Continued
7. Attaching the new control module: (a) If replacing an ECM 2.0 control with an ECM 2.3 control, insert plastic tab into perimeter of replacement control and align tab with mating hole in the end shield. Use the new shorter bolts provided to ensure a secure attachment. Orient the control to the end shield between 4 & 8 o’clock, insert bolts and tighten. (b) If replacing an ECM 2.3 with an ECM 2.3, orient the new control to the motor’s endshield with connectors facing down, insert bolts and tighten. Reinstall the blower/motor assembly into the HVAC system by following the manufacturer’s guidelines. Plug the 16-pin connector and the 5-pin connector back into the motor. The connectors are keyed. Observe proper orientation. 10. Be certain to form a drip-loop so that water cannot enter the motor by draining down the cables (see Figure 5). Final installation check. Ensure the system is setup as follows: (a) Verify the condensate drain is not plugged or clogged. (b) Reconnect the AC power to the HVAC system and verify that the new motor control module is working properly. (c) Check and plug leaks in return ducts and equipment cabinet. (d) The system should run quietly and smoothly. Note: If this is a repeat failure, then it is important that you check the following: Any evidence of moisture requires correcting the issue. Line Transient Voltage Protection Application Note

How do we troubleshoot ECM motors? Rule # 1 – If the motor is running at all. The problem is not in the motor. Rule # 2 – If the motor is running at the wrong RPM/CFM, the most likely cause is the installation or controls sending signals to the ECM motor. Rule # 3 – What is the most common failure mode? Water. Look for signs of moisture damage and correct before replacing end bell. So far I have told you what not to look for and you are still asking your self; How do I test an ECM motor? Rule # 1 – If the motor is running at all. The problem is not in the motor. 96% of the time. This is a big statement, how can I justify this? What is the #1 & #2 failure modes? No Fault found and Moisture. Secondly, When the control fails what is the most likely component(s) to fail? The line voltage controls. When these fail, the motor will not run. Rule # 2 – If the motor is running at the wrong RPM/CFM, the most likely cause is the installation or controls sending signals to the ECM motor. The only exception to this would be if someone has already changed the motor or end bell and installed an incorrect end bell assembly. For Example if someone went out and replaced a BBC motor with a PGD motor thinking there was no difference between the two motors. If someone did this, What do you think the results would be? Why. Rule # 3 – What is the most common failure mode? Water. Look for signs of moisture damage and correct before replacing end bell. Even if you have determined that the interface or control board has failed….Check the end bell for moisture. Moisture is the # 1 cause of failure and if the end bell shorts out, it can cause a failure of the control or interface board. Always check for sign of moisture inside the end bell.

Rule # 4 - ECM motors, like any motor must have a power supply. Check the incoming power supply. Inductor I AC Line Gnd Pin 1 & 2 must be connected together for 120Vac input applications AC Line 5 4 3 2 1 } V Rule # 4 - ECM motors like any motor must have a power supply. Check the incoming power supply to the motor. Unplug the 5 Pin connector at the motor and check for incoming power. Caution !! You will be checking this with line voltage present. Exercise appropriate caution. The line voltage to the motor is not switched. There should be power to the motor, any time there is power to the unit. The inductor shown, is used on ¾ & 1 hp – 120 volt applications only. The inductor is a current limiting device used to reduce the inrush current during start up. This also reduces the minimum circuit Ampacity for the furnace. That means you can’t remove the inductor after installation. ½ HP and 208/230 volt applications do not have an inductor as shown in the example. } Power Connector (viewed from plug end) Inductor is used on ¾ & 1 hp – 120 VAC applications only.

TSTAT Connections Pin number Common C W/W Common C Delay tap select Cool tap Select Y Adjust tap select Output Return valve (heat pump only) Humidistat (BK) Heat tap select VAC (R) nd stage heat (EM/W2) nd stage cool (Y/Y2) Fan (G) Output + Control (male) Connector (female)

Rule # 5 - ECM motors, like any motor must have a signal or switch to turn it on, or tell it to run. Controls should be checked with a true RMS meter or analog meter. Controls will activate at ½ nominal voltage and 12 milliamps. Out 8 5 4 3 2 1 6 7 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Common 1 9 (Rev Valve) ECM motors do not function well with cheep thermostats or power robbing thermostats. These thermostats can drive you crazy trying to troubleshoot problems because they can bleed enough voltage to cause intermittent problems or false signals. One of the first steps in troubleshooting is to disconnect the thermostat from the unit. Use a handy box or jumper wires to provide thermostat input. This is especially true if you are using a non-Amana thermostat. What you want to do is to take the thermostat out of the equation. Make certain the problem is in the unit, not false signals from the thermostat. Control Connector Cable Half (viewed from connector end)

Check power to control. Pins 1 to 12 and 3 to 12. You must have 24 VAC. Set thermostat to demand for cooling. Check for 24 VAC at pins 1 to 6 and 3 to 6. If you don’t record voltage as noted, repeat test at control or interface board. Out 8 5 4 3 2 1 6 7 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Common 1 9 (Rev Valve) Check power to control. Pins 1 to 12 and 3 to 12. You must have 24 VAC. The motor control (end bell) must have power to function, Pins 1 to 12 and 3 to 12 must have 24 volts anytime there is power to the unit. Set thermostat to demand for cooling. Check for 24 VAC at pins 1 to 6 and 3 to 6. You are looking for a clean signal for the motor to operate to cooling speed. You could also check for heat signal (pins 1 to 2 or 3 to 2) or fan only signal (pins 1 to 15 and 3 to 15). The point is, if the motor operates in any one mode, it will operate in all the other modes. Remember back earlier in this discussion. Moisture is the # 1 failure, and in almost all failures the line voltage components failed. Either it runs or it doesn’t. If you don’t record voltage as noted, repeat test at control or interface board. Why would I want you to do this? (you are Checking the harness) If you record voltage the the control board, what does it tell you? (Harness is bad) Control Connector Cable Half (viewed from connector end)

If control is defective, remove end bell and inspect for moisture before replacing control board. Do not apply power to pins 8 or 16. Do not apply line voltage to control connections. Out 8 5 4 3 2 1 6 7 16 Out + Adjust +/- 15 G(fan) Y1 14 Y /Y2 Cool 13 EM Ht/W2 Delay 12 24VAC (R) Common 2 11 Heat W /W1 10 BK/PWM (Speed) Common 1 9 (Rev Valve) If control is defective, remove end bell and inspect for moisture before replacing control board. WHY ??? You checked it out and the control is bad, so why are you playing around with the motor? (If the motor shorts out, it may cause the control or interface to fail) Do not apply power to pins 8 or 16. What does 8 & 16 do anyway? (pins 8 and 16 provide the output for the CFM light flash) Do not apply line voltage to control connections. Either of these actions will cause immediate failure of the end bell assembly. Control Connector Cable Half (viewed from connector end)

Disconnect all power to unit. Disconnect 5 pin and 16 connectors from end bell. Remove end bell assembly (2 Screws. Disconnect 3 pin motor connector. Using Ohmmeter, check for continuity in windings. Using Ohmmeter, check for short to ground. I have told you and told you….It’s not the motor. But you have to check it out for yourself. How do you do it? How do you check the motor? Remember, It’s a three phase motor. Just like any other three phase motor, you check for continuity through the windings and for a short to ground. Since it has a permanent magnet rotor, you don’t worry about a bad rotor…Unless it explodes. But if that happens you can figure it out. Summary Do you remember back at the start of this discussion, I told you that ECM motors last longer than PSC motors? How or why could I be right? What kills electric motors? Over heated motor windings, which causes the insulation to breakdown and ultimately causes the winding to short! Most damage to electric motors occurs on start up! The windings generate a great deal of heat until the motor gets up to speed (RPM). The more often a motor starts and the greater the starting load, the shorter the life of the motor. The ECM motor, on the other hand, uses a permanent magnet rotor (near 0 slippage) and ramp the motor up slowly using the power frequency. This avoids the big heat build up associated with PSC motors. Less heat = longer life. A controlled ramp up sequence reduces the stress and strain on the motor couplings so that the blower wheel last longer also. If we learn to properly trouble shoot the ECM motors, we can immediately cut 80% of our warranty field replacements. If we learn to address or correct the excess moisture in the motors, we can cut another 16% of our warranty field replacements. When we accomplish these two things, the ECM motor will have a lower failure rate than standard motors. (IE longer life) Motor Connector

any questions? Thank you!

GMV9, and GCV9 TUBULAR GAS FURNACE.

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