Hoval Chronic pressure loss

Furnace frequently loses pressure and needs topping up

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.

Possible Causes

Small leak in system pipework or radiators, Leaking plate heat exchanger in Hoval unit, Faulty expansion vessel Schrader valve, Micro-leaks at automatic air vents

How to Fix / Troubleshooting

Safety: Repeated topping up introduces oxygen and can cause corrosion.

Inspect for damp: Check around radiators, valves, and under the furnace for signs of water staining.
Check PRV discharge: Look at the pressure relief valve outlet; if it is wet, the valve may be passing.
Monitor pressure: Note the pressure cold and hot; large swings suggest expansion vessel issues.
Service visit: A technician should test the expansion vessel and inspect the internal heat exchanger for leaks.

Repair Difficulty

Hard 4/5

Required Part

Expansion Vessel

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