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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 perform 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 performs a
hard lockout on the compressor. The user
can select either two or four times by
changing switch four (4) on the DIP switch
SW1 (shown on table 3) on the UPM board.
Low pressure protection
If the LPC 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 two (2) times for the LPC
and the alarm contact will remain off.
If the compressor is running in normal mode
on a Y call and the low pressure switch
opens, the UPM will keep the compressor
running for two (2) minutes if the condition
remains after this period of time the
compressor will shut down and the UPM will
start a soft lockout. The UPM will flash two
(2) times for the LPC. And the alarm contact
will remain off.
If the switch closes, the UPM will start the
compressor after the anti short cycle has
expired UPM will energize the compressor
output.
IMPORTANT:
To exit the hard lockout the controller must
be reset from the Y or R terminal by
removing the power from the selected
terminal. The user can choose which will be
the reset point via the DIP switch SW1.
6
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