Table of Contents
Advertisement
6 | Freeze Sensor
FREEZE SENSOR
This is optional and can be set to ignore or monitor a
freeze sensor. There are 2 configurable freeze points,
30°F and 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 may not
provide protection in the case of loss of flow in the
heating mode. A flow switch or pressure differential
switch is recommended to prevent unit operation in case
of loss of flow.
UNIT PROTECTION MODULE (UPM)
The Unit Protection Module (UPM) as shown in figure 1, is
a printed circuit board (PCB) that inter faces with the
thermostat or the digital direct controller.
The main purpose of this device is to protect the
compressors by monitoring the different states of
switches and sensors of each refrigerant circuit, this
device provides time delays and protects the unit against
freezing of the water and refrigerant heat exchangers as
well as condensate overflow when the appropriate
sensors are installed (Figure 1).
Figure 1—Refer to unit wiring diagram for
connection details
Alarm output is Normally Open (NO) dry contact. If 24
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.
POWER RANDOM START UP
This feature prevents multiple units sharing same
electrical circuit or network from starting at the same
time.
It assures that Heat Pumps sharing the same electrical
circuit do not demand high inrush currents
simultaneously when star ting back up after a power
failure.
970-293 (2014/06)
If the controller has been completely powered down for
more than 28 milliseconds, a random delay is initiated
typically the unit will start between the time range of 270
and 300 seconds, this only if the controller is set to
normal operation (test switch set to NO).
In order for the random sequence to initiate the unit
power must be removed completely.
Caution
ANTI SHORT CYCLE DELAY
This feature protects the compressor short cycling if the
Y call is set and removed.
The anti short cycle delay is 300sec delay on break during
normal operation.
Caution
Y CALL
The UPM will energize the compressor's output (CC) in
an event of a "Y" call from a thermostat or controller
(after the random start up and/or the anti short cycle
delays have elapsed). Y input terminal must be energized
with a 24 VAC signal.
HIGH AND LOW PRESSURE PROTECTION
The UPM monitors the state of the High and Low pressure
Switch inputs of each refrigerant circuit, HPC and LPC on
the board respectively, these switches must be closed in
order for the controller to energize the compressor output
(CC). The CC output will only be energized when the
switches are closed and the anti short cycle (and /or
random start up when applicable) has expired.
HIGH PRESSURE PROTECTION
If the HPC switch is open upon a Y call the UPM will not
energize the CC output and therefore the compressor
will remain off, the fault LED will flash one (1) time for
the HPC and the alarm contact will remain off.
If the compressor is running in normal mode on a Y call
and the high pressure switch opens, the UPM will shut
down the compressor output and will keep it off until the
switch closes and the anti short cycle has expired. The
controller will keep track of the number of times the
switch opens, if within one (1) hour period the switch
opens the number of times set via the DIP switch the
controller will shut the compressor down and per form a
hard lockout condition under this condition the alarm
contact will be energized.
The UPM allows the user to configure the counts that the
HPC will be allowed to open within one hour before the
UPM per forms a hard lockout on the compressor. The
Subject to change without prior notice
IMPORTANT: If the board is set to " TEST "
mode through the " TEST " DIP switch SW1
delay will be 10 seconds.
NOTE: If the board is set to test mode through
the " TEST " DIP switch the delay will be 5
seconds.
Console Model
CA Series
Hide quick links:
Advertisement
Table of Contents
