Lennox GCM07N, Service Manual, Page: 27 / 39

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8.4 Protection
8.4.1 3 minutes delay at restart for compressor.
8.4.2 Sensor protection at open circuit and breaking disconnection
8.4.3 Fan Speed is out of control. When Indoor Fan Speed is too high(higher than High Fan+300RPM)or
too low(lower than 400RPM), the unit stops and LED displays failure information and can’t returns to
normal operation automatically.
8.4.4 Cross Zero signal error warning. If there is no Cross Zero signals in 4 minutes, the unit stops and LED
displays failure information and can’t returns to normal operation automatically.
8.4.5 The current protection of the compressor
Condition Indoor fan Compressor Outdoor fan Remark
I< I
RESTORE
On On On
On On Off Heating mode I
RESTORE
<I< I
FAN
Low speed On On Cooling mode
I
FAN
<I<I
5MIN
Off Off After 5 Minutes
Current up
I
5MIN
<I< I
3SEC
Off Off After 3 Seconds
I
5MIN
<I< I
3SEC
Off Off After 3 Seconds
I
FAN
<I<I
5MIN
Off Off After 5 Minutes
On On Off Heating mode I
RESTORE
<I< I
FAN
Low speed On On Cooling mode
Current down
I< I
RESTORE
On On On
If compressor turns off for continuously 4 times due to current protection in 5 minutes from
Compressor On, the unit stops and LED displays failure information and can’t returns to normal
operation automatically.
8.5 Fan-only mode
Fan speed is high/mid/low/ Auto
8.6 Cooling mode
The 4-way valve is closed at cooling mode.
The action of the compressor and the outdoor fan:
Condition
T=Indoor Temp.
Ts=Setting Temp.
Compressor Outdoor fan
T> Ts+1 On On Room temp. up
T<Ts+1 Off Off
T> Ts On On Room temp. down
T<Ts Off Off
Auto fan at cooling mode:
Condition
T=Indoor Temp.-Setting Temp.
Indoor fan speed
T<4 Low
4 <T<5 Med.
Room temp. up
T>5 High
T> 4 High
1 <T<4 Med.
Room temp. down
T<1 Low