Defrost Control; Base Pan Heater Control Logic; Troubleshooting The Base Pan Heater Error; Discharge Sensor Protection - GE ASH220NCDWA Service Manual

Defrost Control

In the heating mode and along with the ambient sensor, the
defrost sensor monitors the temperature of the outdoor
coil to determine if defrost is needed. If the compressor has
been running for 10 minutes continuously and for 45 minutes
overall, the difference between the ambient sensor (Ta) and
the defrost sensor (Te) will be checked. The system will
initiate the defrost cycle if the following conditions can be met
for 5 continuous minutes:
Te ≤ C x Ta-A
Te: Defrost temperature sensor
Ta: Ambient temperature
C: 0.80 if Ta < 32°F/0°C, 0.60 if Ta ≥ 32°F/0°C
A: 8, moderate climate (factory setting). 6, severe climate
(alternate setting)
End Defrosting:
Unitary:
If the defrost sensor (Te) detects the temperature of the
outdoor coil is above 44°F(7°C) for 60 seconds or is above
54°F(12°C) for 30 seconds, the defrost cycle will terminate. If
these temperatures cannot be reached, the defrost cycle will
118℃
automatically terminate in 10 minutes.
Timed Defrost Option:
115℃
• When the outdoor ambient temperature sensor detects Ta
is less than 32°F(0°C)
112℃
• In heating mode, compressor runs continuously for 60
minutes or for 240 minutes in all
109℃
• When the above conditions are met, the system will defrost.
Defrosting frequency is 68 HZ, with a defrosting time of 8
105℃
minutes.
95℃

Discharge Sensor Protection

If the discharge temperature is higher than normal, the compressor will slow down to lower the temperature.
Multi:
243℉( 117℃)
234℉( 112℃)
225℉( 107℃)
207℉( 97℃)
203℉( 95℃)
B-12
Operations

Base Pan Heater Control Logic

When the compressor starts in the heating mode, the
following conditions will apply:

Troubleshooting the Base Pan Heater Error:

Step 1:
Check the pan heater for an open circuit or shirt circuit.
Unplug the connector from main control PCB. Test the
resistance between the two pins of the pan heater connector.
It should be 0.28-0.379KΩ. If out of range, change the pan
If keeping for 10s, the unit stops, 3 minutes later, the unit can
heater. If normal go step 2.
re-startup. If in 60 minutesthe unit occurs alarm for 3 times, the
failure can be eliminated.
Step 2:
Check the main control board pan heater output port . Unplug
the connector from main control PCB. Run the ODU with
Reduce FQY rapidly 2HZ/S
manually forced heating (Set the display board SW 1-1 as
ON). Test the voltage between the two heater output pins, it
Reduce FQY rapidly 1HZ/S
should be 208-230Vac.
Reduce FQY slowly 1HZ/10S
Remain FQY
Increase FQY slowly 1HZ/10S
If the discharge temperature sensor reaches 243F for 10
seconds, the compressor will shut off. After the 3-minute
time delay, the compressor will restart. If this occurs
three times in a 60-minute period, the compressor will
lock out. Until the cause of the high temperature is
discovered, the compressor will not restart until the
power is interrupted then restored.
Reduce FQY rapidly 1HZ/S
Reduce FQY slowly 1HZ/10S
Remain FQY
Increase FQY slowly 1HZ/10S
Remain FQY
OUTDOOR TECHNICAL OVERVIEW
Outdoor Temperature
o o
>37 F(3 C)
o o o o
28 F(-2 C) to 34 F(1 C)
o o o o
10 F(-12 C) to 25 F(-4 C)
o o
<10 F(-12 C)
Pan Heater
OFF
OFF 20min. ON 10min.
OFF 15min. ON 15min.
ON