41
When adjusting the compressor pressure regulating
valve (CPR), the unit must be running in heating or
defrost mode. This will ensure a suction pressure
above the proper CPR setting. To adjust the CPR valve,
proceed as follows:
a.
Install a gauge on the suction line .
b.
Remove cap from CPR valve.
c.
With an 8 mm Allen wrench, loosen the
jam nut.
d.
Using the 8 mm Allen wrench, adjust the
set screw. To raise the suction pressure
turn the set screw clock-wise, to lower
the suction pressure, turn counter-
clockwise
e.
When the setting has been adjusted,
tighten the jam nut securely against the
set screw. This will prevent
any
movement of the set screw due to
vibrations in the unit. Replace the cap.
The compressor must be protected this is the reason
why the valve should be set at the maximum suction
pressure to safely operate the compressor.
CPR VALVE SETTING IS 29 PSIGG
4.16 TESTING DEFROST SYSTEM
To test the defrost system, run the unit on cool until the
evaporator coil temperature is below
35.0 ± 5.4° F and press the manual defrost switch.
If the unit doesn’t shift to defrost cycle, check the
evaporator temperature.
Be sure the evaporator temperature is actually below 35.0
± 5.4° F, otherwise the unit will not defrost. Use a test
thermometer to check the evaporator temperature.
If the unit cab-command shows defrost mode but the unit
is not defrosting. Refer to section
4.12 for diagnosis of Solenoid coils and valves.
Figure 26 - CPR valve adjustment
