ASPT Service Manual
Table Of Contents
- IMPORTANT INFORMATION
- PRODUCT IDENTIFICATION
- Checking Voltage
- Checking Wiring
- Checking Thermostat And Wiring
- Thermostat Wiring
- Checking Transformer And Control Circuit
- Checking Contactor And/Or Relays
- Checking Contactor Contacts
- Checking Fan Relay Contacts
- Checking Loss Of Charge Protector (Heat Pump Models)
- Checking High Pressure Control
- Checking Low Pressure Control
- Copeland Comfort Alert™ Diagnostics - 3-Wire module
- Copeland Coresense™ Diagnostics - 3-Wire module
- Checking Capacitor
- Resistance Check Using A Digital Multi-Meter
- Capacitance Check Using A Digital Multi-Meter (In Capacitance Mode)
- Testing a Run Capacitor Under Load
- Checking Outdoor Fan and Blower Motors (PSC Motors)
- Checking Fan and Blower Motor (ECM Motors)
- Checking ECM Motor Windings
- ECM CFM Adjustments MBE/AEPF
- Blower Performance Data
- Checking High Efficiency Motors
- EEM Blower Replacement
- MBR/AR*F Electronic Blower Time Delay Relay
- Checking Compressor
- Resistance Test
- Ground Test
- Unloader Test Procedure
- Operation Test
- Checking 3-Phase Scroll Compressor Rotation
- Testing Crankcase Heater (Optional Item)
- Checking Reversing Valve and Solenoid
- Testing Defrost Control
- Testing Defrost Thermostat
- Checking Heater Limit Control(s)
- Checking Heater Elements
- Electric Heater (Optional Item)
- Checking Heater Limit Control(s)
- Checking Heater Elements
- Refrigeration Repair Practice
- Leak Testing (Nitrogen or Nitrogen-Traced)
- Evacuation
- Charging
- Checking Compressor Efficiency
- Overfeeding
- Underfeeding
- Checking Superheat
- Subcooling on Expansion Valve System
- Checking Expansion Valve Operation
- Checking Restricted Liquid Line
- Overcharge Of Refrigerant
- Non-Condensables
- Compressor Burnout
- Refrigerant Piping
- Duct Static Pressures
- Single Piece Air Handler External Static
- Two Piece Air Handler External Static Pressure
- Furnace External Static Pressure
- Periodic Maintenance
SERVICING
87
6. If ground is indicated, replace the compressor. The
resistance reading should be infinity. If there is any
reading on meter, there is some continuity to ground and
compressor should be considered defective.
Compressor Ground Test
WARNING
Unloader Test Procedure
A nominal 24-volt direct current coil activates the
compressor internal unloader solenoid. The input control
circuit voltage must be 18 to 28 volt ac. (remove) The
coil power requirement is 5 VA. The external electrical
connection is made with a molded plug assembly. This plug
contains a full wave rectier to supply direct current to the
unloader coil. The measured DC voltage at the connectors
in the plug should be 15 to 27 volt dc.
Unloader Test Procedure
If it is suspected that the unloader is not working, the
following methods may be used to verify operation.
1. Operate the system and measure compressor amperage.
Cycle the unloader ON and OFF at 10 second intervals.
The compressor amperage should increase when
switching from part-load to full-load and decrease when
switching from full-load to part-load. The percent change
depends on the operating conditions and voltage, but
should be at least 25 percent.
2. If step one does not give the expected results, shut unit
o. Apply 18 to 28 volt ac to the unloader molded plug
leads and listen for a click as the solenoid pulls in. Remove
power and listen for another click as the unloader returns
to its original position.
3. If clicks can’t be heard, shut o power to the unit and
remove the control circuit molded plug from the compressor
and measure the unloader coil resistance (connections on
the compressor). The solenoid coil should have continuity
and not be grounded or have innite resistance. If the coil
resistance is innite, zero, or grounded, the compressor
must be replaced.
4. Next check the molded plug.
a. Voltage check: Apply control voltage to the plug wires (18
to 28 volt ac). The measured dc voltage at the female
connectors in the plug should be around 15 to 27 vdc.
b. Resistance check: Measure the resistance from the
end of one molded plug lead to either of the two female
connectors in the plug. One of the connectors should
read close to zero ohms while the other should read
infinity. Repeat with other wire. The same female
connector as before should read zero while the other
connector again reads innity. Reverse polarity on the
ohmmeter leads and repeat. The female connector that
read innity previously should now read close to zero
ohms.
Replace plug if either of these test methods doesn’t show
the desired results.
Operation Test
If the voltage, capacitor, overload and motor winding test
fail to show the cause for failure:
WARNING
1. Remove unit wiring from disconnect switch and wire a test
cord to the disconnect switch.
and type.
2. With the protective terminal cover in place, use the three
leads to the compressor terminals that were disconnected
at the nearest point to the compressor and connect the
common, start and run clips to the respective leads.
3. Connect good capacitors of the right MFD and voltage
rating into the circuit as shown.
4. With power ON, close the switch.