F24
Protherm Rapid Temperature Rise / Pump Protection

F24 displayed, appliance may start then quickly shut down, temperatures rise too fast

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Pump not running or air-locked, Blocked primary circuit, Incorrect pump speed setting, Faulty pump relay on PCB

How to Fix / Troubleshooting

Safety first: Turn off power and allow the unit to cool.

  • Check pump: On models with an internal pump, remove the pump vent plug and attempt to turn the shaft with a screwdriver. If stuck, free or replace the pump.
  • Bleed air: Bleed the pump and system to remove trapped air.
  • Check wiring: Verify that the pump is receiving power when the appliance calls for heat. If not, the PCB or relay may be faulty.
  • Replace pump or PCB: If the pump is defective, replace it with the correct Protherm pump assembly. If the pump is good but not powered, replace or repair the PCB.

Warning: Do not run the heater with a seized pump; this can cause overheating and damage.

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Repair Difficulty

Hard 4/5

Required Part

Primary Circulation Pump
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