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 starting
back up after a power failure.
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.
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.
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, HP1, LP1 and HP2 and
LP2 on the board respectively, these
switches must be closed in order for the
controller to energize the compressor output
(CC1 and CC2). 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.
NOTE:
If the board is set to test mode through the “TEST”
DIP switch the delay will be 5 seconds.
IMPORTANT:
If the board is set to “TEST” mode through the
“TEST” DIP switch SW1 delay will be 10 seconds.
5
