Medium
1.5 on Malvern TenTwenty

Your boiler's internal water pressure is too low, which is preventing it from circulating heat effectively around your home.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Bar Vessel Pressure (Vessel Volume 8, 12, 12, 18, 24)

From this model's manual
Verified against the Malvern Tentwenty installation & service manual, page 6.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Locate the filling loop (usually a silver braided hose with one or two valves) under your boiler.Open the valve(s) slowly to allow mains water to enter the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valve(s) tightly to stop the flow and check that the fault code has cleared.

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