Technical data

8 TROUBLE SHOOTING
8.1 General Requirements
Units are not generally user serviceable and no attempt
should be made to rectify any faults found with the unit
unless suitably qualified and equipped to do so. If in any
doubt, contact your local York Agent. To avoid personal
injury or possible damage to the unit, the trouble
shooting information given in the following section must
only be used by competent service personnel using
correct procedures and equipment.
8.2 Trouble Shooting
In any case where the control panel detects conditions
or control functions requiring the unit to stop, it will shut
down the unit and display the reason for the shutdown.
Most shutdowns will be due to normal cycling of the unit
due to lack of load, scheduled off cycles etc., but others
may be caused by an internal or external fault detected
by the control panel. For a full description of the
operation of each of these shutdown functions refer to
the control panel Operation Instruction.
In the case of shutdowns caused by cycling contacts, or
by other conditions unlikely to cause an ongoing
problem, the control panel will automatically restart the
unit as soon as the contacts or conditions allow the unit
to run. If, however, this type shutdown occurs
unexpectedly or repeatedly, a problem may exist which
requires attention.
For shutdowns caused by conditions which may lead to
damage to the unit, the control panel will require a
manual reset before allowing a restart. In this situation it
is essential to determine the exact cause of the
shutdown and rectify the problem before putting the unit
back into service.
Some operating conditions are not monitored by the
control panel such as compressor wear, oil condition,
water treatment levels, etc. Detection of any potential
problems caused by these conditions relies on daily
monitoring of the unit and by regular service inspections
- see Sections 6 & 7.
The possible causes and recommended actions listed in
these tables should be used for guidance only and
should not be considered exhaustive.
160.81-ICOM-GB0 (01/02) 8-1
Fault Possible Cause Remedy
Abnormally High Discharge Pressure
Temperature difference between
condensing temperature and
condenser leaving liquid temperature
higher than normal.
Air in condenser. Bleed cooling water circuit.
High discharge pressure. Condenser tubes dirty or scaled. Clean condenser tubes. Check water
treatment.
High condenser water temperature. Reduce condenser water inlet
temperature. (Check cooling tower
and water circulation.)
Temperature difference between
condenser entering liquid and
condenser leaving liquid higher than
normal, with normal evaporator
pressure.
Insufficient condensing water flow. Increase the water flow through the
condenser to correct value.
Abnormally Low Suction Pressure
Temperature difference between
leaving chilled water and refrigerant in
evaporator greater than normal with
high discharge temperature.
Insufficient charge of refrigerant. Check for leaks and charge
refrigerant into system.
Variable orifice problem. Remove obstruction.
Temperature difference between
leaving chilled water and refrigerant in
the evaporator greater than normal
with normal discharge temperature.
Evaporator tubes dirty or restricted. Clean evaporator tubes.