ClimateMaster Tranquility TSM Series - Safety Features - CXM;DXM2 Controls; Anti-short cycle protection; High pressure switch; Water coil low temperature (LT1)

CLIMATEMASTER WATER-SOURCE HEAT PUMPS
TSM/TSL Vertical Stack
Rev.: January 18, 2021
ClimateMaster Water-Source Heat Pumps
64
Safety Features – CXM/DXM2 Controls
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 ashing 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 satised, 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 (DXM2 board) or by going into test mode
(CXM board). Note: LT1/LT2 faults are factory set at only
one try.
Lockout: In lockout mode, the status LED will begin fast
ashing. 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 DXM2 is congured for heat pump thermostat
type (DIP 1.3), emergency heat will become active if O/
W2 is energized.
For LED fault codes and alarm relay output for CXM
see table 8 and DXM2 see table 9.
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). Note: For units with motorized water valve -
One high pressure water switch is in series with refrigerant
high pressure switch and will cause fault if pressure is 300
PSI (reset at 240 PSI).
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.
Water coil low temperature (LT1): The LT1 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 LT1 fault.
The LT1 input is bypassed for the initial 120 seconds of a
compressor run cycle. LT1 is set at the factory for one try.
Therefore, the control will go into lockout mode once the
LT1 fault has occurred.
Air coil low temperature (LT2): The LT2 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 LT2 fault.
The LT2 input is bypassed for the initial 60 seconds of a
compressor run cycle. LT2 is set at the factory for one try.
Therefore, the control will go into lockout mode once the
LT2 fault has occurred.
Condensate overow: The condensate overow sensor
must sense overow level for 30 continuous seconds to
be recognized as a CO fault. Condensate overow will be
monitored at all times.
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/DXM2 is in over/under voltage shutdown for 15
minutes, the alarm relay will close.
Unit Performance Sentinel-UPS: The UPS feature
indicates when the heat pump is operating inefciently. A
UPS condition exists when:
a. In heating mode with compressor energized, LT2
is greater than 125°F [52°C] for 30 continuous
seconds, or:
b. In cooling mode with compressor energized, LT1
is greater than 125°F [52°C] for 30 continuous
seconds, or:
c. In cooling mode with compressor energized, LT2 is
less than 40°F [4.5°C] for 30 continuous seconds.
If a UPS condition occurs, the control will immediately
go to UPS warning. The status LED will remain on as
if the control is in normal mode. Outputs of the control,
excluding LED and alarm relay, will NOT be affected
by UPS. The UPS condition cannot occur during a
compressor off cycle. During UPS warning, the alarm
relay will cycle on and off. The cycle rate will be “on” for 5
seconds, “off” for 25 seconds, “on” for 5 seconds, “off” for
25 seconds, etc.
Swapped LT1/LT2 thermistors: During test mode, the
control monitors to see if the LT1 and LT2 thermistors are
in the appropriate places. If the control is in test mode, the
control will lockout with code 9 after 30 seconds if: