8 | Electrical TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
The UPM Board includes the following features:
• ANTI-SHORT CYCLE TIMER: 5 minute delay on
break timer to prevent compressor short cycling.
• RANDOM START: Each controller has an unique
random start delay ranging from 270 to 300 seconds
on initial power up to reduce the chance of multiple
unit simultaneously starting at the same time after
power up or after a power interruption, thus
avoiding creating large electrical spike.
• LOW PRESSURE BYPASS TIMER: If the compressor
is running and the low pressure switch opens, the
controller will keep the compressor ON for 120
seconds. After 2 minutes if the low pressure switch
remains open, the controllers will shut down the
compressor and enter a soft lockout. The
compressor will not be energized until the low
pressure switch closes and the anti-short cycle time
delay expires. If the low pressure switch opens 2-4
times in 1 hour, the unit will enter a hard lockout. In
order to exit hard lockout power to the unit would
need to be reset.
• BROWNOUT/SURGE/POWER INTERRUPTION
PROTECTION: The brownout protection in the UPM
board will shut does the compressor if the incoming
power falls below 18 VAC. The compressor will
remain OFF until the voltage is above 18 VAC and
ANTI-SHORT CYCLE TIMER (300 seconds) times out.
The unit will not go into a hard lockout.
• MALFUNCTION OUTPUT: Alarm output is Normally
Open (NO) dry contact. If pulse is selected the alarm
output will be pulsed. The fault output will depend
on the dip switch setting for "ALARM". If it is set to
"CONST", a constant signal will be produced to
indicate a fault has occurred and the unit requires
inspection to determine the type of fault. If it is set
to "PULSE", a pulse signal is produced and a fault
code is detected by a remote device indicating the
fault. See L.E.D Fault Indication below for blink code
explanation. The remote device must have a
malfunction detection capability when the UPM
board is set to "PULSE".
• DISPLAY OUTPUT: The Display output is a pulse
output connected to the Unit Diagnostic Display
(UDD) and it pulses 24VAC when the unit is in an
lockout alarm condition.
• TEST DIP SWITCH: A test dip switch is provided to
reduce all time delays settings to 10 seconds during
troubleshooting or verification of unit operation.
• FREEZE SENSOR: The default setting for the freeze
limit trip is 26°F (sensor number 1); however this
can be changed to 15°F by cutting the R24 resistor
located on top of the DIP switch SW1. Since freeze
sensor 2 is dedicated to monitor the load side coil it
is recommended to leave the factory default setting
on the board. The UPM controller will constantly
monitor the refrigerant temperature with the sensor
mounted close to the condensing water coil
between the thermal expansion valve and water coil.
If temperature drops below or remains at the freeze
limit trip for 30 seconds, the controller will shut the
compressor down and enter into a soft lockout
condition. Both the status LED and the Alarm
contact will be active. The LED will flash (three (3)
times) the code associated with this alarm
condition. If this alarm occurs 2 times (or 4 if Dip
switch is set to 4) within an hour the UPM controller
will enter into a hard lockout condition. It will
constantly monitor the refrigerant temperature with
the sensor mounted close to the evaporator
between the
thermal expansion valve and
UPM Board Factory Default Settings
TEMP
26°F
LOCKOUT
2
RESET
Y
ALARM
PULSE
TEST
NO
UPM DIP SWITCH DEFAULT POSITION
lockout 42
reset
RY
alarm
Cont pulse
test
yes no
If 24 VAC output is needed, R must be wired to
ALR-COM terminal; 24 VAC will be available o the
ALR-OUT terminal when the unit is in the alarm
condition.
NOTICE: Operation of unit in test mode can
lead to accelerated wear and premature
failure of components. The "TEST" switch
must be set back to "NO" after
troubleshooting/servicing.
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