Service manual

CLIMATEMASTER WATER-SOURCE HEAT PUMPS
32
ClimateMaster Water-Source Heat Pumps
Genesis GR Series
Revised: 9 August, 2011
Safety Features
Safety Features – CXM/DXM Control
The safety features below are provided to protect
the compressor, heat exchangers, wiring and other
components from damage caused by operation
outside of design conditions.
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 (DXM
board) 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 thermostat (or satisfying the call). A
“soft” reset keeps the fault in memory but resets the
control. A “hard” reset (disconnecting 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. If DXM is configured for heat pump thermostat
type (DIP 1.3), emergency heat will become active if O/
W2 is energized.
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 pressure 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
compressor power up it will be considered a low pressure
(loss of charge) fault. The low pressure switch input is
bypassed for the initial 120 seconds of a compressor
run cycle.
Low pressure lockout code = 3
Water coil low temperature (FP1): The FP1 thermistor
temperature 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 bypassed for the initial 120
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
temperature 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 recognized as a CO fault. Condensate overflow will
be monitored at all times.
CO lockout code = 6
Over/under voltage shutdown: An over/under voltage
condition 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/DXM is in over/under voltage
shutdown for 15 minutes, the alarm relay will close.
Over/under voltage shut down code = 7