C L I M A T E M A S T E R W A T E R - S O U R C E H E A T P U M P S
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C l i m a t e M a s t e r W a t e r- S o u r c e H e a t P u m p s
Tr a n q u i l i t y
®
W a t e r- t o - W a t e r T H W S e r i e s
R e v i s e d : 0 2 J a n u a r y, 2 0 1 3
Safety Features - CXM Control
Safety Features – CXM 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 fl 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 satisfi 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 (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 fl 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.
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 fl ashes, 10 sec pause, 2 quick fl ashes,
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
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 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 52°C for 30 continuous seconds, or:
b) In cooling mode with compressor energized, FP1 is
greater than 52°C for 30 continuous seconds, or:
c) In cooling mode with compressor energized, FP2 is
less than 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.
UPS warning code = 8
Diagnostic Features
The LED on the CXM board advises the technician of
the current status of the CXM control. The LED can
display either the current CXM mode or the last fault in
memory if in test mode. If there is no fault in memory,
the LED will fl ash Code 1 (when in test mode).
CXM Control Start-up Operation
The control will not operate until all inputs and safety
controls are checked for normal conditions. The
compressor will have a 5 minute anti-short cycle delay
at power-up. The fi rst time after power-up that there is
a call for compressor, the compressor will follow a 5 to
80 second random start delay. After the random start
delay and anti-short cycle delay, the compressor relay
will be energized. On all subsequent compressor calls,
the random start delay is omitted.
