Low Pressure Too High & High Pressure Too High

Test Results
1. Air bubbles visible in sight glass at various times during operation.
2. Line from receiver/dryer to expansion valve very hot.
3. Center vent nozzle temperature too high.

Cause
1. Auxiliary fan not switching on at pressures above 259 psi.
2. Condenser plate surfaces severely damaged.
3. Condenser plates dirty enough to restrict air flow.

Correction
1. Check for mechanical and electrical operation of auxiliary fan, repairing or replacing as necessary.
2. Check electrical operation of three-way pressure switch, repairing or replacing as necessary.
3. Clean end of condenser and, if engine is overheating, check cooling system.
4. Perform operational test.