Lennox MCC Series Installation, Operating And Maintenance

Installation - Operation - Maintenance manual (IOM) • AIR COOLED CHILLERS & SPLIT UNITS - 1106-E • 38 •
8.1 LIST OF THE MOST COMMON PROBLEMS – CONTINUED
PROBLEMS – SYMPTOMS PROBABLE CAUSE RECOMMENDED ACTION
J) THE COMPRESSOR IS NOISY
- If starting on a single winding on
compressors fitted with part winding
start or wye-delta
- Check operation of the starter
contacts, the start up time delay and
the condition of the windings
- Compressor knocking
- Broken mechanical parts inside
compressor
- Replace the compressor
a) Liquid slugging
a) Check superheat and that the
expansion valve bulb is correctly
installed
b) Expansion valve blocked in open
position
b) Repair or replace
- Suction line is unusually cold
- Broken suction valves - Replace broken valves
- High discharge pressure. The water
regulating valve or the pressure
operated water valve taps or knocks
- Pressure operated water valve
fouled, water pressure is to high or
irregular
- Clean the valve. Install and
expansion tank upstream of the
valve
- Compressor shuts down through
action of the oil pressure safety
switch
- Low oil charge - Add oil
K) DISCHARGE PRESSURE TOO HIGH
- Water is far too hot at condenser
outlet
- Water flow to low or water
temperature too high in the
condenser
- Adjust the pressure operated water
valve or the thermostat on the
cooling tower
- Water is far too cold at the
condenser outlet
- Condenser tubes fouled - Clean the tubes
- Condenser abnormally hot
- Presence of air or incondensibles in
the circuit, or excessive refrigerant
charge
- Purge incondensibles and/or air,
and recover excess refrigerant
- Chilled water leaving temperature
too high
- Excessive cooling load
- Reduce load, reduce water flow if
necessary
L) DISCHARGE PRESSURE IS TOO LOW
- Water is very cold at condenser
outlet
- Condenser water flow too high or
water temperature is too low
- Adjust the pressure operated water
valve or the thermostat on the
cooling tower
- Bubbles in sightglass - Low refrigerant charge - Repair the leak and add refrigerant

Lennox MCC Series Specifications

General

Brand	Lennox
Model	MCC Series
Category	Chiller
Language	English