Chaffoteaux Chronic Pressure Loss

Furnace frequently loses pressure and needs topping up often.

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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

Leaking radiator or pipework, Faulty pressure relief valve (PRV) passing water, Ruptured expansion vessel diaphragm, Micro-leaks in heat exchanger

How to Fix / Troubleshooting

Safety: Allow system to cool before inspecting PRV discharge pipe.

  • Check PRV discharge: Locate the pressure relief valve discharge pipe (usually copper, exiting outside). If water drips regularly, the PRV may be passing.
  • Inspect for visible leaks: Check all radiators, valves, and accessible pipes for damp patches or staining.
  • Expansion vessel test (professional): A technician can check the expansion vessel pre-charge via the Schrader valve and recharge or replace it if the diaphragm has failed.
  • Avoid constant topping up: Repeatedly adding fresh water increases corrosion. Find and fix the leak instead.
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Repair Difficulty

Medium 3/5

Required Part

Expansion Vessel
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