Chapter 6—REFRIGERATION AND AIR CONDITIONINGTroubleCompressor short cycles onlow pressure control.Compressor runs continuously.Compressor short cycles onhigh pressure control switch.Compressor will not run.Possible CauseLow refrigerant charge.Thermal expansion valve notfeeding properly.(a) Dirty strainers.(b) Moisture frozen in orificeor orifice plugged withdirt.(c) Power element dead orweak.Water flow throughevaporators restricted orstopped. Evaporator coilsplugged, dirty, or cloggedwith frost.Defective low pressurecontrol switch.Shortage of refrigerant.Leaking discharge valves.Insufficient water flowingthrough condenser, cloggedcondenser.Defective high pressurecontrol switch.Seized compressor.Cut-in point of low pressurecontrol switch too high.High pressure control switchdoes not cut-in.1. Defective switch.2. Electric power cut off.2. Service or disconnectswitch open.Corrective MeasureLocate and repair leaks.Charge refrigerant.Adjust, repair or replacethermal expansion valve.(a) Clean strainers.(b) Remove moirture or dirt(Use system dehydrator).(c) Replace power element.Remove restriction. Checkwater flow. Clean coilsor tubes.Repair or replace low pres-sure control switch.Repair leak and rechargesystem.Replace discharge valves.Determine if water has beenturned off. Check for scaledor fouled condenser.Repair or replace highpressure control switch.Repair or replace compressor.Set L. P. control switch tocut-in at correct pressure.Check discharge pressureand reset H. P. controlswitch.1. Repair or replace switch.2. Check power supply.3. Close switches.54.299.2Figure 6-12.—Trouble diagnosis chart—Continued.6-19
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business