Lainox HIGH PRESSURE

What does Lainox HIGH PRESSURE mean?

The HIGH PRESSURE alarm signals a high-pressure condition on single-phase models, and a high-pressure or compressor thermal-protection condition on three-phase models, detected through the multifunction input. Any cycle that needs the compressor is interrupted, the alarm relay is activated, and the condenser fan is turned on to help shed heat. It points to a refrigeration-side or compressor-protection fault rather than a control error.

Symptoms

• HIGH PRESSURE alarm message appears on the controller.
• Any running cycle that uses the compressor is interrupted.
• Compressor stops while the condenser fan turns on.
• The alarm relay output is activated.
• On three-phase units the compressor's thermal protection may have tripped.

Common causes

• High-pressure switch tripped on the refrigeration circuit.
• Compressor thermal protection tripped (three-phase models).
• Clogged or dirty condenser restricting heat rejection.
• Condenser fan failure or blocked airflow.
• Incorrect multifunction-input polarity setting (parameter i6).
• Refrigerant overcharge or non-condensables in the circuit.

Diagnostic steps

1. 01

   Check the multifunction inlet conditions

   As the manual directs, inspect the multifunction input that signals this alarm to confirm whether the high-pressure or thermal switch has genuinely tripped.

2. 02

   Check the value of parameter i6

   Verify parameter i6 (multifunction inlet polarity) is set correctly; a wrong polarity can falsely trigger or suppress the alarm.

3. 03

   Inspect condenser and airflow

   Check that the condenser is clean and the condenser fan and front grilles are unobstructed, since restricted heat rejection is a common cause of a genuine high-pressure trip.

4. 04

   Allow compressor protection to reset

   On three-phase models, let the compressor cool so the thermal protection can reset before retrying, and confirm the cycle resumes and the alarm relay clears.

When to call a professional

A genuine high-pressure or compressor thermal trip is a refrigeration-circuit condition. If the alarm persists after confirming the input setting and cleaning the condenser, stop using the unit and call a refrigeration technician. Work on the sealed system, pressure switches, refrigerant charge, or compressor must be done by qualified personnel; repeated high-pressure trips can damage the compressor.