Grant Instruments RC - Manual (Page 12)

Recirculating Chiller
Part No 09931/Issue 8 Page 12 August 2001
5 Fault diagnosis
Symptom Cause Reason/Recovery procedure
Power switched on
No power Check that the chiller is connected to the CORRECT power
supply voltage, check all fuses.
Buzzer sounding
Controller displays
1dHi or 2dLo Temperature outside
values set for over- or
undertemperature
alarm The external heating load has increased so that it is too large
for the cooler or the external cooling load has increased so that
it is too large for the heater, so the chiller cannot control to the
desired temperature. There is no recovery. Change the set
temperature or use a more powerful circulator.
Buzzer sounding
General alarm light
on
Flow fail alarm Switch off the power to the chiller. Check the liquid level in the
reservoir. Check that all hoses are connected correctly are
water tight and that there are no blockages, air bubbles or
kinks. If the set temperature is below 5°C
check that the
correct mix of water/glycol is being used (60% water 40%
glycol). Drain or isolate the liquid to the input pipe before
unscrewing and checking the inlet filter which is fitted to the
inlet pipe (this can be checked without removing pipework).
Switch the power on again and press the flow fail override
switch for 5 seconds.
Buzzer sounding
General alarm light
on
Controller displays
1dHi Over temperature cut-
out Over temperature due to malfunction of cooler, heater or flow
fail. A competent technician should reset the cut-out, refer to
the service manual. If the chiller fails to restart contact Grant's
service department.
RC cannot heat to
set temperature Cooler switched on
Switch cooler off. If this has no effect see below.
External cooling load
too large for RC. There is no recovery. Either change the set temperature or use
a more powerful circulator.
RC cannot control
at temperatures
below 4°C External heat source is
too large for chiller
capacity. The external heat load is too large for the cooler so the chiller
can not control to the desired temperature. There is no
recovery. Either change the set temperature or use a more
powerful device.
Cooler not operating Cooler not switched on Switch cooler on. If cooler doesn't start see below.
Undertemperature
thermostat
Check that water/glycol mixture is in the system and switch the
water/glycol switch to water/glycol. If the chiller does not start,
see below.
Compressor over-
temperature thermostat
Check that the front and rear grilles are not obstructed and that
the condenser is free from dust. Allow the compressor to cool
down (typically 20 to 30 minutes); it will automatically switch
on. If unit still does not start see below.
Refrigeration high
pressure cut-out
Switch off and contact Grant service department or arrange for
a competent technician to consult the service manual.
Controller displays
S.br
Alarm lights on
Buzzer sounding
Sensor fault
(if fitted) Check remote probe is plugged in.
Switch off and contact Grant service department.
Controller displays
Err1/2/3
Controller failure Switch off and contact Grant service department.
Controller displays
Err 4 Controller keyboard
failure Switch the power off and then on without touching any of the
controller buttons. If the fault does not clear switch off and
contact Grant service department .