Raypak LIMIT TRIP

What does Raypak LIMIT TRIP mean?

Per the Error Display table, LIMIT TRIP means the heater temperature tripped the high limit. The control detected water temperature exceeding the safe high-limit threshold and shut the heater down to protect the heat exchanger. This is commonly the result of inadequate water flow through the unit, and the corresponding PIM hi-limit guidance directs checking for proper water flow.

Symptoms

• LIMIT TRIP shown as the active error on the display
• Heater lockout on overtemperature
• Red fault LED (7 flashes indicates hi-limit fault on the PIM)
• Often accompanies low or no water flow

Common causes

• Inadequate water flow across the heat exchanger
• Pump failure or air-bound system
• Closed or restricted isolation valves
• Faulty hi-limit or outlet sensor

Diagnostic steps

1. 01

   Check for proper water flow

   Per the PIM hi-limit fault guidance, confirm there is adequate water flow through the heater and that the system pump is running.

2. 02

   Check the hi-limit and outlet sensor

   Inspect the hi-limit setting and the outlet sensor and its wiring for faults.

3. 03

   Purge air and verify valves

   Verify air has been purged from the system and that isolation valves are open so water can circulate freely.

4. 04

   Reset the control

   After restoring flow and confirming the limit components, press and release the RESET button to clear the fault.

5. 05

   Observe operation

   Monitor several cycles to ensure the heater holds temperature without re-tripping the limit.

When to call a professional

A high-limit trip can indicate a flow problem that may damage the heat exchanger if ignored, and the manual cautions that if overheating occurs you should shut off the gas at the service valve rather than killing pump power. Diagnosing pump and flow faults and testing the high-limit circuit on a hot, energized unit should be done by a qualified Raypak service technician if the cause is not an obvious closed valve.