Temperzone UC8 Troubleshooting Guide
15. Protection function details
High pressure protection (HP)
Protects a unit from excessively high refrigerant pressure.
Conditions: Unit with HP switch: When the switch activates (open circuit).
Unit with high pressure transducer: When compressor discharge pressure exceeds 4151
kPa (602 PSI, equivalent to +65°C condensing temperature).
Hydronic reverse cycle units where the high pressure transducer is switched to the
suction line when heating: When the indoor coil temperature exceeds 56°C.
Low pressure protection (LP)
Protects a unit from excessively low refrigerant pressure.
Conditions: Unit with LP switch: As soon as the switch activates (open circuit).
If a low pressure transducer is connected there are two levels:
Transient level: When pressure is below 114 kPa (16.5 PSI, equivalent to -35°C).
Normal level: When pressure is below 228 kPa (33.0 PSI, equivalent to -25°C).
Notes: The transient level is always applied.
The normal level is applied when more than 90 seconds have expired since the compressor
started and also when more than 90 seconds have expired since the end of a de-ice cycle.
Indoor coil frost protection
Protects a unit from forming too much ice on the indoor coil. Applied only when a unit is cooling in
normal mode, not applied when a unit is de-icing the outdoor coil.
The frost protection function activates when the indoor coil condition remains very cold for longer
than the frost-protect delay time of 6 minutes.
Conditions: When the evaporating temperature remains below -8°C for longer than 6 minutes
or when the compressor suction pipe temperature remains below -4°C for longer than
6 minutes.
High temperature protection
Protects the compressor from overheating which could otherwise cause damage to the compressor
motor, to the compression scroll or rotary compression stage, or cause deterioration of the
compressor lubricating oil.
On a unit with electric heating protects the unit from becoming extremely hot and burn-out of the
electric heating element.
Conditions: When the compressor discharge pipe temperature remains above
+120°C for longer than 2 seconds or
+110°C for longer than 30 minutes.
Hydronic units with electric heating only:
When the fast-acting heating safety temperature sensor (connected to input AMB)
remains above +75°C for longer than 2 seconds.
To Next Page
Loading...
Need help?
General