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Plumbing

new combi boiler & overflow dripping - are they related?

Anonymous user 28/02/2024 - 4.00 PM

We recently replaced our system boiler with a combi. At the same time we drained and capped off the cold water tank and removed the hot water cylinder from the airing cupboard. The issue we're seeing is that the overflow pipe in the eaves (I assume from the cold water tank) is dripping fairly consistently during the day. The combi boiler has also dropped it's pressure down to under 0.5 in less than the 2 weeks we've had it fitted. I just can't see how the overflow pipe can be dripping - I've been up into the loft and both the cold water tank and expansion tanks are still bone dry.... so where is the water coming from? I can only think that somehow the central heating pipes which still run into the loft from where the hot water cyclinder sat are still connected somehow to the cold water pipes and into the overflow???? Is the overflow drip somehow related to the combi losing it's pressure so quickly?

Are you a tradesperson and able to answer this question?

4 Answers

SB Heating & Gas Services

Rating: 5 out of 5

Glasgow

if your combi pressure is dropping and the overflow is dripping there's a good chance the pressure relief valve inside the boiler is letting by, would get someone out to have a look and test/replace if needed

Answered13 May 2021

LLYN CAMBRIAN ELECTRICAL PLUMBING

Rating: 4.8 out of 5

Wrexham

Ok let’s be logical about this Have you traced the overflow back from where it leaves the eaves as if it was the overflow from the tanks then if the tanks are empty you indeed have a peculiar situation as the pipe should not be connected elsewhere If it is trace back to the source Pressure reducing is not uncommon during first few weeks of usuage as some air may have been left in the system especially if the system was not run at maximum temperature when commissioned If problem continues a small leak is probably to blame Surely whilst understanding your reasoning to post this question it is the responsibility of the installer to rectify Gas safe company I trust

Answered14 May 2021

Anonymous user

You must have a hole in your roof and the rain could be coming in and running down the over Flo pipe give it a few weeks untill the sun comes out and it should be fine then .

Answered30 May 2021

Barry Constable

Rating: 5 out of 5

Thornton Heath

The only reason for this answer to be correct, is if the new Combi-boiler is fitted in the loft. If this isn't the case then there must be an old pipe that is still connected going to the cold water storage tank or feed and expansion tank.

Answered10 June 2021