• Evaporator freeze protection sensor, mounted after the thermal
expansion device and the evaporator, monitors refrigerant
temperature between the evaporator coil and thermal expansion
valve. If temperature drops below or remains at freeze limit trip
for 30 seconds, the controller will shut down the compressor and
enter into a soft lockout condition. The default freeze limit trip is
30°F. See Fig. 11.
A14122
Fig. 11 - Evaporator Freeze Protection Sensor Location
The UPM includes the following features:
• ANTI-SHORT CYCLE TIME--5 minute delay on break timer
to prevent compressor short cycling.
• RANDOM START--Each controller has a unique random start
delay ranging from 270 to 300 seconds to reduce the chances of
multiple units simultaneously starting after initial power up or
after a power interruption, creating a large electrical spike.
• LOW PRESSURE BYPASS TIMER--If the compressor is
running and the low pressure switch opens, then the control will
keep the compressor on for 120 seconds. After 2 minutes, if the
low pressure switch remains open, the control 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 and need to be
reset.
• BROWNOUT /SURGE /POWER INTERRUPTION
PROTECTION--The brownout protection in the UPM board
will shut down the compressor if the incoming power falls below
18 VAC. The compressor will remain off until the voltage goes
above 18 VAC and the 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. If24 VAC output is needed, R must be wired to
the ALR-COM terminal; 24VAC will be available on the
ALR-OUT terminal when the unit is in alarm condition. If pulse
is selected the alarm output will be pulsed. The fault output will
depend on the dip switch setting for "ALARM". If it 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
LED Fault Indication below for blink code explanations. The
remote device must have a malfunction detection capability when
the UPM board is set to "PULSE".
LED
provided.
GREEN:
FAULT INDICATION -Two LED Indicators are
Power LED indicates 118-30 VAC present at the
board.
RED: Fault indicator wit blink codes as follows:
• One Blink - High pressure lockout
• Two Blinks - Low pressure lockout
• Three Blinks - Freeze sensor lockout
• Four Blinks - Condensate overflow
• Five Blinks - Brownout
TEST DIP SWITCH--A test dip switch is provided to reduce all
time delay settings to 10 seconds during troubleshooting or
verification of unit operation. Note that operation of the unit while
in test mode can lead to accelerated wear and premature failure of
the unit. The "TEST" switch must be set back to "NO" for normal
operation.
FREEZE SENSOR_The freeze sensor input is active all the
time, if a freeze option is not selected the freeze terminals will
need a jumper. There are 2 configuraMe freeze points, 26°F &
15 °F. The unit will enter a soft lock out until the temperature
climbs above the set point and the anti-short cycle time delay has
expired. The freeze sensor will shut the compressor output down
after 90 seconds of water flow loss and report a freeze condition. It
is recommended to have a flow switch to prevent the unit from
running if water flow is lost.
UNIT DAMAGE AND/OR OPERATION HAZARD
Failure to follow this caution may result in unit damage
and/or improper equipment operation.
If unit is employing a fresh water system (no anti-freeze
protection), it is extremely important to have the "Freeze"
jumper R30 resistor set to 26°F in order to shut down the
unit at the appropriate leaving water temperature and
protect your heat pump from freezing if a freeze sensor is
included.
• EVAPORATOR FREEZE SENSOR--Evaporator freeze
protection sensor, mounted after the thermal expansion device
and the evaporator, monitors refrigerant temperature between the
evaporator coil and thermal expansion valve. If temperature drops
below or remains at freeze limit trip for 30 seconds, the controller
will shut down the compressor and enter into a soft lockout
condition. The default freeze limit trip is 30°F.
• INTELLIGENT RESET--If a fault condition is initiated, the 5
minute delay on break time period is initiated and the unit will
restart after these delays expire. During this period the fault LED
will indicate the cause of the fault. If the fault condition still exists
or occurs 2 or 4 times (depending on 2 or 4 setting for Lockout dip
switch) before 60 minutes, the unit will go into a hard lockout and
requires a manual lockout reset. A single condensate overflow
fault will cause the unit to go into a hard lockout immediately, and
will require a manual lockout reset.
•LOCKOUT RESET--A hard lockout can be reset by turning
the unit thermostat off and then back on when the "RESET" dip
switch is set to "Y" or by shutting off unit power at the circuit
breaker when the "RESET" dip switch is set to "R".
NOTE: The blower motor will remain active during a lockout
condition.
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