High Discharge Pressure

Probable Cause: Remedy:
Air or noncondensables in condenser.
Dirty condenser.
Poor or no condensing water flow.
Water supply to condenser too warm.
Purge noncondensables.
Clean condenser.
Check water supply, strainers, and pump.
Check, repair, and adjust condenser water cooling facilities.
Find cause of air flow blockage and correct.
Correct the air flow direction.
Reselect properly sized components.
Air flow is restricted thru condenser.
Wrong air flow direction thru condenser.
Incorrectly sized condenser fan blade, fan motor, or both.
Condenser fan motor not running, or wrong rotation.
Liquid refrigerant backed up in condenser.
Find source of problem and correct.
Refrigerant overcharge.
Receiver too small for flooded head pressure control system in summer operation.
Fan pressure switch out of calibration.
Higher rate of infiltration of ambient air inside cabinet than designed
(panel missing, or exhaust fans from elsewhere discharging under or close to condenser air intake).
Check for faulty flooded type head pressure control valves.
Charge to proper levels.
Replace with correct size liquid receiver.
Recirculation of condenser air.
Condenser tubing restricted (physical damage or internal restriction).
Change air flow direction.
Replace condenser.
Ambient conditions exceeding design. Reevaluate design.
Failure of flooded head pressure control system (constant bypass)
Pressure drop through condenser exceeds 20 psi, forcing bypass port partially open.
Bypass port wedged open due to foreign material between seat and seat disc.Bypass port seat damaged or worn.
Wrong pressure dome in valve for system’s refrigerant.
By check valve in backwards.
Pressure of condenser bypass regulator(OPR) set too high.
Repipe, recircuit, or change condenser to reduce pressure drop below 20 psi.
Artificially reduce head pressure and tap valve body with system running to
dislodge foreign material.
Change valve.
Change dome or valve to match the system’s refrigerant and desired pressure.
Install in proper flow direction.
Adjust condenser bypass regulator’s setting to appropriate level. Normally set
20 psi below the condenser pressure regulator’s (IPR) setting.