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Plumbing

Pressure in unvented cylinder keeps varying

Anonymous user 03/03/2024 - 3.44 PM

I recently had an unvented cylinder installed that seems to lose pressure quite randomly. Couple of weeks back my circulation pump went bust and the pressure was 0 (probably why the circ pump failed). After the pump was replaced, I fixed a camera to continuously monitor the pressure gauge. I can see that the pressure varies - went down a bit and then up again occasionally (between 1.2 and 1.5 bar). But now, after about 5 days, the pressure has dropped significantly over a two hour period and has stayed low (around 0.5 bar). I am away so the heating is set to just frost protection mode, so it is highly unlikely that the boiler has come on during this period. Adding an update: When I got back and turned the heating back on, the pressure got restored again on its own. Not sure what's happening.

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4 Answers

Anonymous user

I would check for a faulty pressure relief valve
Answered2 January 2023
1

GasGasGas Heating and Plumbing by Kevin Hough Ltd

Rating: 5 out of 5
Alfreton
If there are no obvious leaks anywhere on the system, the expansion vessels will need checking for correct pressure. If they are satisfactory and no leaks on the system then possibly fault with PRV.
Answered2 January 2023
1

Lewis Blunderfield

No reviews yet

Bury St Edmunds
Or a damaged expansion vessel
Answered10 January 2023
0

Positive Glow Ltd

Rating: 5 out of 5
Cheltenham
The unvented cylinder doesn’t generically have a pressure gauge. If it is piped into the side of the cylinder it is probably part of the heating system circuit. Thebunvented cylinder has a pressure reducing valve to hold a pressure (normally 3bar) if pressure is inconsistent then I’d be looking at a service required to the expansion vessel. The issue you seen to be having is on the heating system. As you best the water with the boiler there is pressure increases. This is like most things when you heat them they expand!! So a little increase I wouldn’t be concerned with if its fluctuation is between 1-2bar. If it’s falling then you have a loss of pressure or a leak which could be caused by a multiple different reasons. Get yourself an engineer to help you find the issue
Answered15 January 2023
0