Refrigeration troubleshooting guides

85 guides. Walk-ins, reach-ins, ice machines and other commercial refrigeration problems. Each one lists the likely causes and what to check, in order.

All brands (85)

• Attic very hot / mildew / ice dams
  Possible causes and checks for: attic very hot / mildew / ice dams.
• Both sections too warm
  Possible causes and checks for: both sections too warm.
• Coldest evaporator warms on off cycle / poor refrigeration in coldest case
  Possible causes and checks for: coldest evaporator warms on off cycle / poor refrigeration in coldest case.
• Compressor locked out on pressure control
  Possible causes and checks for: compressor locked out on pressure control.
• Compressor noisy soon after charging
  Possible causes and checks for: compressor noisy soon after charging.
• Compressor short cycles on LPC after shutdown
  Possible causes and checks for: compressor short cycles on lpc after shutdown.
• Compressor stops or overloads on start
  Possible causes and checks for: compressor stops or overloads on start.
• Compressor won't start (general procedure)
  Possible causes and checks for: compressor won't start (general procedure).
• Cracked lines, leaks at fittings
  Possible causes and checks for: cracked lines, leaks at fittings.
• Cubes too small
  Possible causes and checks for: cubes too small.
• Cut-out on high head pressure / discharge temperature
  Possible causes and checks for: cut-out on high head pressure / discharge temperature.
• Cycles on overload
  Possible causes and checks for: cycles on overload.
• Doesn't complete cycle
  Possible causes and checks for: doesn't complete cycle.
• Doesn't fill with water
  Possible causes and checks for: doesn't fill with water.
• Door freezes shut
  Possible causes and checks for: door freezes shut.
• Evaporator excessively warm / never frosts
  Possible causes and checks for: evaporator excessively warm / never frosts.
• Evaporator iced up
  Possible causes and checks for: evaporator iced up.
• Freezer too cold
  Possible causes and checks for: freezer too cold.
• Fresh-food section too cold
  Possible causes and checks for: fresh-food section too cold.
• Fresh-food section too warm
  Possible causes and checks for: fresh-food section too warm.
• Frost/ice on finned evaporator
  Possible causes and checks for: frost/ice on finned evaporator.
• Frost/sweat back on suction line; liquid to compressor
  Possible causes and checks for: frost/sweat back on suction line; liquid to compressor.
• Frost/sweat on suction line to compressor
  Possible causes and checks for: frost/sweat on suction line to compressor.
• Gradual loss of freezing capacity
  Possible causes and checks for: gradual loss of freezing capacity.
• High amps / overload at start
  Possible causes and checks for: high amps / overload at start.
• High head pressure
  Possible causes and checks for: high head pressure.
• High head pressure / scaling
  Possible causes and checks for: high head pressure / scaling.
• High superheat, starved evaporator, low suction, partial frost on coil
  Possible causes and checks for: high superheat, starved evaporator, low suction, partial frost on coil.
• High-pressure control trips
  Possible causes and checks for: high-pressure control trips.
• Hunting / surging suction pressure and superheat swings
  Possible causes and checks for: hunting / surging suction pressure and superheat swings.
• Ice in drip catcher
  Possible causes and checks for: ice in drip catcher.
• Ice on lower fins, airflow blocked
  Possible causes and checks for: ice on lower fins, airflow blocked.
• Knocking / slugging / broken valves, blown head gasket
  Possible causes and checks for: knocking / slugging / broken valves, blown head gasket.
• Liquid refrigerant reaching compressor
  Possible causes and checks for: liquid refrigerant reaching compressor.
• Liquid to compressor during defrost / defrost won't terminate
  Possible causes and checks for: liquid to compressor during defrost / defrost won't terminate.
• Low superheat, floodback, suction line sweating/frosting to compressor, compressor knock
  Possible causes and checks for: low superheat, floodback, suction line sweating/frosting to compressor, compressor knock.
• Low-pressure control / safety trips
  Possible causes and checks for: low-pressure control / safety trips.
• Metering device orifice freezing, sludge/acid
  Possible causes and checks for: metering device orifice freezing, sludge/acid.
• Noisy
  Possible causes and checks for: noisy.
• Oil drained is dark, pungent, has metal chips
  Possible causes and checks for: oil drained is dark, pungent, has metal chips.
• Oil safety control trips
  Possible causes and checks for: oil safety control trips.
• Oil separator not returning oil / too much oil in system
  Possible causes and checks for: oil separator not returning oil / too much oil in system.
• Oil-pressure control trips
  Possible causes and checks for: oil-pressure control trips.
• One case too cold / too warm; erratic cycling
  Possible causes and checks for: one case too cold / too warm; erratic cycling.
• Overfilled recovery cylinder, rising ambient
  Possible causes and checks for: overfilled recovery cylinder, rising ambient.
• Overheating / burnout, metal chips in system
  Possible causes and checks for: overheating / burnout, metal chips in system.
• Pressure drops over 1 h / 24 h
  Possible causes and checks for: pressure drops over 1 h / 24 h.
• Pressure rises ≥10 psi within 5 min after recovery
  Possible causes and checks for: pressure rises ≥10 psi within 5 min after recovery.
• Pressure/temperature control faults (refrigerators, coolers, freezers)
  Possible causes and checks for: pressure/temperature control faults (refrigerators, coolers, freezers).
• Product partially thawed / ice crystals on product; box warms during defrost
  Possible causes and checks for: product partially thawed / ice crystals on product; box warms during defrost.
• Pump won't pull a deep vacuum
  Possible causes and checks for: pump won't pull a deep vacuum.
• R-410A charged into R-22 components
  Possible causes and checks for: r-410a charged into r-22 components.
• Recovery slow
  Possible causes and checks for: recovery slow.
• Refrigerant loss with no visible leak
  Possible causes and checks for: refrigerant loss with no visible leak.
• Refrigerant migration / flooded compressor after power failure
  Possible causes and checks for: refrigerant migration / flooded compressor after power failure.
• Refrigerant/oil leak at shaft
  Possible causes and checks for: refrigerant/oil leak at shaft.
• Repeat compressor burnout
  Possible causes and checks for: repeat compressor burnout.
• Runs all the time
  Possible causes and checks for: runs all the time.
• Runs all the time, temp normal
  Possible causes and checks for: runs all the time, temp normal.
• Runs all the time, too cold
  Possible causes and checks for: runs all the time, too cold.
• Runs all the time, too warm
  Possible causes and checks for: runs all the time, too warm.
• Short cycling
  Possible causes and checks for: short cycling.
• Sight glass bubbles
  Possible causes and checks for: sight glass bubbles.
• Sight glass shows bubbles
  Possible causes and checks for: sight glass shows bubbles.
• Starved evaporator / low capacity
  Possible causes and checks for: starved evaporator / low capacity.
• Stuck compressor
  Possible causes and checks for: stuck compressor.
• Suction line heavily frosted at start-up, compressor struggles to start, possible slugging
  Possible causes and checks for: suction line heavily frosted at start-up, compressor struggles to start, possible slugging.
• Suction pressure/temperature drops too low, system cycles off early, coil freezes
  Possible causes and checks for: suction pressure/temperature drops too low, system cycles off early, coil freezes.
• System pressures don't match P/T chart / high head with normal load
  Possible causes and checks for: system pressures don't match p/t chart / high head with normal load.
• Thermal overload trips repeatedly
  Possible causes and checks for: thermal overload trips repeatedly.
• Tube pitting or scaling
  Possible causes and checks for: tube pitting or scaling.
• TXV chatters/opens on off cycle (display case door openings)
  Possible causes and checks for: txv chatters/opens on off cycle (display case door openings).
• Uneven coil temperatures, part of coil warm
  Possible causes and checks for: uneven coil temperatures, part of coil warm.
• Uneven oil levels between compressors
  Possible causes and checks for: uneven oil levels between compressors.
• Unit runs excessively long or continuously
  Possible causes and checks for: unit runs excessively long or continuously.
• Unit will not run
  Possible causes and checks for: unit will not run.
• Vacuum rises then levels off above 500 microns
  Possible causes and checks for: vacuum rises then levels off above 500 microns.
• Vacuum won't reach target or rises steadily after isolating
  Possible causes and checks for: vacuum won't reach target or rises steadily after isolating.
• Valve won't open on warm start / long pull-down
  Possible causes and checks for: valve won't open on warm start / long pull-down.
• Water overflow / drain pan full / condensate pump alarm
  Possible causes and checks for: water overflow / drain pan full / condensate pump alarm.
• Won't cut in / won't cut out
  Possible causes and checks for: won't cut in / won't cut out.
• Won't start cycle
  Possible causes and checks for: won't start cycle.
• Won't start, hums or trips overload
  Possible causes and checks for: won't start, hums or trips overload.
• Works, then warms up (repeating)
  Possible causes and checks for: works, then warms up (repeating).
• Zeotropic (400-series) system performing poorly after a vapor charge or after a large leak
  Possible causes and checks for: zeotropic (400-series) system performing poorly after a vapor charge or after a large leak.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.