SRL Service Manual
Revision 00
July 2007
Page 39 of 56
10.2 Troubleshooting
Alarms
&
Warnings
10.2.1 High Pressure (Alarm)
What it means:
High pressure switch registers a refrigerant pressure above 406 psig (28 barg).
What it does:
Cuts power to compressor contactor & alarm contacts. Turns the 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.
6)
Incorrect start-up procedure
. Compressed air was allowed to flow through the dryer
before it was started, causing an immediate HP alarm on start up.
Remedy – Isolate the dryer from the air flow by closing the inlet and outlet isolation valves
and opening the bypass line. Start the dryer with no air flow. You may need to start the
dryer repeatedly before the alarm clears.
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 304 psig (21 barg).