Lennox DM - Page 46

DC-DM-ROOFTOP-IOM-1801-E - 44 -
CODE DESCRIPTION CONDITION EFFECT RESET POSSIBLE CAUSES POSSIBLE REMEDIES
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217
Circuit 2, Safety Low
Pressure, Cut-off.
The suction temperature
calculated by the LP pressure
sensor is lower than the
permitted threshold.
Threshold: < -27°C,
Delayed: 2min,
Waiting stop: 30min,
Enabled: 6min after one
compressor start.
Or
Threshold: < -33°C,
Delayed: Immediately,
Enabled: immediately.
Stop C2
compressors.
3/day
or
Manually
• Refrigerant charge • Check the circuit operating [2446]
218
Circuit 2, Water Evaporator,
Risk of Frosting.
The suction temperature
calculated by the LP pressure
sensor is lis too low and may
pose a risk for the water
evaporator.
Threshold: [3513] 0% Glycol <
0°C,
Threshold: [3513] 50% Glycol <
-20°C,
Delayed: 5s,
Waiting stop: 6min,
Enabled: 2s after one
compressor start in heating
mode.
Stop C2
compressors.
6/day
• Limit indoor/outdoor
temperature conditions,
• Refrigerant charge,
• Problem with the expansion
valve.
• Wait normal tempetaure
conditions,
• Check the circuit operating,
• Replace the expansion valve.
[2442]
219
Circuit 2 Compressor,
Condensing T°, Too Low.
The temperature measured by
the probe is outside of the
permitted range.
Threshold: < 21.5°C,
Delayed: 6min,
Waiting stop: 30min,
Enabled: 3min after one
compressor or condenser fan
start/stop.
Signalling. Automatic
• Limit indoor/outdoor
temperature conditions,
• Refrigerant charge,
• Problem with the expansion
valve.
• Wait normal tempetaure
conditions,
• Check the circuit operating,
• Replace the expansion valve.
#
221
Circuit 2, Superheat T°, Too
Low.
The value calculed is outside of
the permitted range.
Threshold: < [3621] - 3K,
Delayed: 6min,
Waiting stop: 6min,
Enabled: 6min after one
compressor start, then 3min
after one compressor or
condenser fan start/stop.
Stop C2
compressors.
3/day
• Limit indoor/outdoor
temperature conditions,
• Refrigerant charge,
• Problem with the expansion
valve.
• Wait normal tempetaure
conditions,
• Check the circuit operating,
• Replace the expansion valve.
[2636]