Presentation is loading. Please wait.

Presentation is loading. Please wait.

HVAC Commercial Ref. All commercial Refrigerators will have at least these 6 component 3 loads Compressor Condenser Fan Evaporator Fan 3 required accessories.

Similar presentations


Presentation on theme: "HVAC Commercial Ref. All commercial Refrigerators will have at least these 6 component 3 loads Compressor Condenser Fan Evaporator Fan 3 required accessories."— Presentation transcript:

1 HVAC Commercial Ref

2 All commercial Refrigerators will have at least these 6 component 3 loads Compressor Condenser Fan Evaporator Fan 3 required accessories Thermostat Starting Relay Start capacitor

3 HVAC Commercial Ref This drawing is the minimum required components wired for a Single Phase Medium Temperature Refrigerator

4 HVAC Commercial Ref When a contactor is used the thermostat is replaced by the contacts of the contactor If it is a 2 pole contactor the second set of contacts are placed in the L2/N to the compressor and condenser fan The thermostat and safety controls are wired in series with the contactor coil

5 HVAC Commercial Ref If a liquid line solenoid the thermostat controls the solenoid The compressor will cycle on low pressure caused by the system pumping down when the solenoid is closed

6 HVAC Commercial Freezer Next lets break down a commercial Freezer wiring

7 HVAC Commercial Freezer The brain of the commercial Freezer is the Defrost timer There are 2 types of timers one is time on- time off, The other is time on-time or temperature off Terminal identification will often change among manufactures so understanding timer operation is important!!

8 HVAC Commercial Freezer Before adding controls and motors you need to understand the basics The timer motor is on as soon as power is supplied The normally closed contacts, in this case 1 to 4 are for cooling The normally open contacts in this case 2 to 3 are defrost The oval between 1 and 2 represents a jumper that can be removed This timer is time- temperature off or terminated the “X” terminal is connected to the “Drop Solenoid” which changes the switch contacts back to cooling if the temperature at the evaporators indicates it has been defrosted

9 HVAC Commercial Freezer Add each system to the wiring diagram separately Here the cooling components are wired

10 HVAC Commercial Freezer Next the defrost components are added

11 HVAC Commercial Freezer Next the defrost termination components are added Note the evaporator fan L2 is now connected to the DTS to delay starting the fan after a defrost

12 HVAC Commercial Freezer Next the defrost components are added

13 HVAC Commercial Freezer Next the defrost components are added

14 HVAC Commercial Freezer If a contactor is used to operate the compressor The thermostat and safety control are wired in series with the contactor coil The contactor contacts replace the thermostat on both sides of the compressor and condenser fan “package”

15 HVAC Commercial Freezer If a Liquid line Solenoid is used the thermostat will control the solenoid The low pressure control will turn of the compressor when the pressure drops after the thermostat opens de-energizing the LLS closing the solenoid causing unit to pump down

16 HVAC Commercial Freezer If no contactor is used the low pressure and other safety controls will be wired in series with the compressor “package” The low pressure control will turn of the compressor when the pressure drops after the thermostat opens de-energizing the LLS closing the solenoid causing unit to pump down

17 HVAC Commercial Freezer If the condensing unit is outside or when a fan cycler is need this control is wired in series with the condenser fan

18 HVAC Commercial Freezer Remember when developing wiring diagrams work with each system one at a time After all system are drawn check sequence of operation to see if all systems operate properly


Download ppt "HVAC Commercial Ref. All commercial Refrigerators will have at least these 6 component 3 loads Compressor Condenser Fan Evaporator Fan 3 required accessories."

Similar presentations


Ads by Google