Comfort-Aire HWW120 - Manual (Page 22)

21
Safety Features: CXM Controls
The safety features below are provided to protect the com-
pressor, heat exchangers, wiring and other components
from damage caused by operation outside of design condi-
tions.
Anti-short cycle protection: The control features a 5 minute
anti-short cycle protection for the compressor.
Note: The 5 minute anti-short cycle also occurs at power up.
Random start: The control features a random start upon
power up of 5-80 seconds.
Fault Retry: In Fault Retry mode, the Status LED begins
slowly flashing to signal that the control is trying to recover
from a fault input. The control will stage off the outputs and
then “try again” to satisfy the thermostat input call. Once the
thermostat input call is satisfied, the control will continue on
as if no fault occurred. If 3 consecutive faults occur without
satisfying the thermostat input call, the control will go into
“lockout” mode. The last fault causing the lockout will be
stored in memory and can be viewed at the “fault” LED or by
going into test mode (CXM board). Note: FP1/FP2 faults
are factory set at only one try.
Lockout: In lockout mode, the status LED will begin fast
flashing. The compressor relay is turned off immediately.
Lockout mode can be “soft” reset by turning off the thermo-
stat (or satisfying the call). A “soft” reset keeps the fault in
memory but resets the control. A “hard” reset (disconnect-
ing power to the control) resets the control and erases fault
memory.
Lockout with emergency heat: While in lockout mode, if W
becomes active (CXM), emergency heat mode will occur.
High pressure switch: When the high pressure switch opens
due to high refrigerant pressures, the compressor relay is
de-energized immediately since the high pressure switch is
in series with the compressor contactor coil. The high pres-
sure fault recognition is immediate (does not delay for 30
continuous seconds before de-energizing the compressor).
High pressure lockout code = 2
Example: 2 quick flashes, 10 sec pause, 2 quick flashes, 10
sec. pause, etc.
Low pressure switch: The low pressure switch must be open
and remain open for 30 continuous seconds during “on”
cycle to be recognized as a low pressure fault. If the low
pressure switch is open for 30 seconds prior to compres-
sor power up it will be considered a low pressure (loss of
charge) fault. The low pressure switch input is bypassed for
the initial 60 seconds of a compressor run cycle.
Low pressure lockout code = 3
Water coil low temperature (FP1): The FP1 thermistor tem-
perature must be below the selected low temperature limit
setting for 30 continuous seconds during a compressor run
cycle to be recognized as a FP1 fault. The FP1 input is by-
passed for the initial 60 seconds of a compressor run cycle.
FP1 is set at the factory for one try. Therefore, the control
will go into lockout mode once the FP1 fault has occurred.
FP1 lockout code = 4
Air coil low temperature (FP2): The FP2 thermistor tempera-
ture must be below the selected low temperature limit setting
for 30 continuous seconds during a compressor run cycle to
be recognized as a FP2 fault. The FP2 input is bypassed for
the initial 60 seconds of a compressor run cycle. FP2 is set
at the factory for one try. Therefore, the control will go into
lockout mode once the FP2 fault has occurred.
FP2 lockout code = 5
Condensate overflow: The condensate overflow sensor must
sense overflow level for 30 continuous seconds to be recog-
nized as a CO fault. Condensate overflow will be monitored
at all times.
CO lockout code = 6
Over/under voltage shutdown: An over/under voltage condi-
tion exists when the control voltage is outside the range of
19VAC to 30VAC. Over/under voltage shut down is a self-
resetting safety. If the voltage comes back within range for
at least 0.5 seconds, normal operation is restored. This is
not considered a fault or lockout. If the CXM is in over/under
voltage shutdown for 15 minutes, the alarm relay will close.
Over/under voltage shut down code = 7
Unit Performance Sentinel-UPS (patent pending): The UPS
feature indicates when the heat pump is operating ineffi-
ciently. A UPS condition exists when:
a) In heating mode with compressor energized,
FP2 is greater than 125°F [52°C] for 30 continu-
ous seconds, or:
b) In cooling mode with compressor energized,
FP1 is greater than 125°F [52°C] for 30 continu-
ous seconds, or:
Installation & Operation WATER-TO-WATER (HWW) SERIES Heat Controller, Inc.