Follett HI PRESSURE

What does Follett HI PRESSURE mean?

On the Horizon icemaker, if refrigeration pressure rises above 425 psi, a hard error occurs and the HI PRESS (red) alarm LED illuminates. Because it is a hard error, the machine will not restart even after pressure falls back below the 295 psi reset point; the fault must be cleared with the reset button. This protects the system from continued operation at excessive discharge pressure.

Symptoms

• HI PRESS (red) alarm LED illuminated on the control board.
• Machine shut off and not restarting on its own.
• Pressure does not auto-clear even after dropping below the 295 psi reset point.
• High discharge pressure or hot, restricted condenser airflow.

Common causes

• Refrigeration discharge pressure exceeding 425 psi.
• Dirty or blocked condenser reducing heat rejection (air-cooled).
• Ambient air above the 100 F maximum or restricted intake and exhaust grilles.
• Water-cooled condenser water supply problem or fouling.
• Overcharge or non-condensables in the refrigeration system.

Diagnostic steps

1. 01

   Confirm the hard error

   Verify the HI PRESS LED is lit and that the machine stays off, since this is a hard error that will not self-clear after pressure drops below 295 psi.

2. 02

   Clean and clear the condenser

   On air-cooled models clean the condenser coil and confirm the intake and exhaust grilles provide adequate open area, since restricted heat rejection raises high-side pressure.

3. 03

   Check the operating environment

   Confirm ambient air is within the 50 to 100 F range and the required clearances are present, as out-of-spec ambient drives discharge pressure up.

4. 04

   Check water-cooled condenser

   For water-cooled units verify condenser water flow and the factory-set discharge pressure regulation, since loss of condenser cooling raises high-side pressure.

5. 05

   Reset after correction

   Once the cause is corrected, press the reset button to clear the hard HI PRESSURE error; pressure falling below the reset point alone will not restart the machine.

When to call a professional

A high-pressure lockout points to the sealed refrigeration system, where the manual requires all service be performed per federal, state and local law and warns that recharging to other than factory specifications voids the warranty. Diagnosing charge, non-condensables or a condenser fault, and any work on the refrigerant circuit, should be done by an EPA-certified Follett-authorized technician. Do not attempt to defeat the high-pressure lockout.