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Plumbing

Pressure loss on expansion

Anonymous user 23/02/2024 - 3.45 PM

Hi Need help I have a heat only boiler and an unvented cylinder I have also got rid of the tank in the loft and put a expansion vessel in for the heating.Problem I am having is for start when the hot water comes on it drips through the tundish also I seem to lose pressure on the expansion vessel for the heating.Sometimes the pressure will hold for a few days then only drops when the boiler is off.It has had a new pressure relief valve on the hot water cylinder could they be linked.ALso I have put leak sealant in the system just in case.Alsoeven when the pressure is on zero when the heating has fired up the pressure rises to two bar anyway help please.No water in the expansion vessel that seems ok

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4 Answers

Anonymous user

Hi, this sounds like your expansion vessel has failed and needs replacing. The sudden rise in pressure when fired indicates that it’s probably full of water and the diaphragm has split.
Answered11 February 2022
6

D & R Property and Plumbing Maintenance

Rating: 4.9 out of 5
New Romney
expansion vessel failure or expansion vessel not big enough ,if you have water dripping into tundish on cylinder you need to get a g3 qualified plumber to look at it.
Answered11 February 2022
0

KMC Plumbing & Heating Services

No reviews yet

Southport
Expansion vessel failure due to a split diaphragm inside the vessel and worker must of undertaken G3 unvented course to perform task.
Answered12 February 2022
0

M.T.H SERVICES

Rating: 4.9 out of 5
Birmingham
It sounds like the expansion vessel has lost its charge . You can repressure vessel with a pump . And then test it if problem is still happening , it is best to change vessel .
Answered3 March 2022
0