SRC Service Manual
Revision 02
Aug 2007
10.2 Troubleshooting Alarms & Warnings
10.2.1 High Pressure (Alarm)
What it means: High pressure switch registers a refrigerant pressure above 406 psig.
What it does: Cuts power to compressor contactor & alarm contacts. Turns dryer OFF. Turns on
Warning Light & blinks “HP” on the digital display.
Possible Causes & Remedies:
1)
High ambient temperature in the compressor room due to:
a. Warm weather,
b. Poor compressor room ventilation,
c. Poorly located dryer (restricted air flow through the condenser),
d. Compressor aftercooler is exhausting warm air near the dryer.
Remedy - increase ventilation to the compressor room, duct the compressor after-
cooler out of the room, or move the dryer to a cooler location.
2) The
condenser is dirty causing a reduction of air flow and/or cooling if the
refrigerant.
Remedy - Clean the condenser coils and condenser pre-filter (if applicable) by
blowing compressed air backwards through them. Be careful not to bend the fins.
3) The
condenser fan is not coming on because of a failure of the fan motor, contacts,
or pressure switch. (Can be confirmed by checking the condensing pressure with a
gauge.)
Remedy - Replace the detective component.
4)
Excessive thermal load on the dryer due to excessive air flow rate and/or air inlet
temperature. (Can be confirmed using the instructions in Section 13.)
Remedy – Improve the efficiency of the aftercooler on the compressor, install an
additional or larger air or water cooled aftercooler upstream the dryer, or install a
larger dryer. If the overload is limited to a very short period of time, this alarm can
be avoided by partially opening the air by pass line to reduce the load to the dryer.
Please note that this will significantly increase the downstream dew point.
5)
Defective high pressure switch. (Can be confirmed by checking the condensing
pressure with a gauge.)
Remedy - Replace the detective component.
To Reset: Press ALARM RESET. Power restored to alarm relay, Warning Light goes off.
Dryer remains OFF. Display clears.
Press ON/OFF to restart dryer.
Notes: Alarm can only be cleared if the pressure is below 305 psig.
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