Open vented system - overspill and new ceiling leak

[whwend]

I am looking for some advice please on my ceiling leak which appeared today.

I have a standard open vent system in my home and today noticed a nasty brown stain on the ceiling directly below the F&E tank and some pipework. Its quite small 5cmx2cm but appeared when neither CH or HW on. I've outlined it in pencil.

Background is that last week I turned on the central heating briefly but forgot all the rads were turned down at the TRVs. So there was not a lot the CH could heat up. about 10minutes later after some loud knocking and a very unhappy sounding system - I turned it straight off put a jumper on and thought nothing more about it....until today. HW has continued to function fine since.

I got up into the loft space to see what corresponds to today's new stain and its give-or-take pretty much by the header tank which had a plywood lid put on in spring 2023. That plywood has evidence of water staining and the hole for the vent pipe is a bit small (IMHO) to line up well so I have moved that sideways to ensure any pumping over gets into the tank!

So my question is - do you think that my demand for CH while all rads were off was enough for system to pump into F&E and the overspill is just coming through now via thick insulation, tile offcuts etc and now showing on the ceiling.... ? Can I wait for a few days before rushing to call a plumber to see what the stain does from here or should I just get on with paying for someone to come out? Is it just wishful hoping that its last week's misadventure showing through and that just isn't possible?

i couldn't see any other evidence of leaks but its a small well insulated space and all pipes lagged etc so very hard to tell on my own.

I tried to upload some pics but it doesn't let me?
Any advice welcomed Thanks W

 

[terryplumb]

Show us some pics please.

 

[whwend]

- Thanks for your reply I keep getting an 'your photo is too big' but this one has loaded up

 

[whwend]

Screen grab seems to work?

 

[whwend]

I can't work out how this maps above ceiling exactly with joists etc but its right in middle of ceiling and approx distance from loft hatch as measured.

I am hoping it was an return via vent pipe overspill due to lid that took some time to work through ceiling?. I've moved the lid cover sideways for now

 

[Madrab]

Certainly judging by the water staining on that board covering the cistern, it seems to have been pumping over at some point.

 

[terryplumb]

The vent pipe needs to be properly installed so it sits into the cistern through the lid. I agree with Madrabs observation ,the system appears to have been pumping over ,and likely the source of the leakage onto ceiling

 

[whwend]

Thank you both, I have moved the board round and can keep an eye on it without rushing into things. If ceiling stain gets bigger, there might be more to it - but it doesn't sound too urgent for now. I'll have the pipe/cover sorted during upcoming boiler service (august).
Is the pumping over an issue in itself? Or did I perhaps force the system to do it by turning all the radiators off and putting the heating on?

 

[kidgreen61]

I always suggest to customers that they leave their TRVs fully open all summer, this helps to prevent them from sticking in the closed position, a problem for which I get amillion calls every October.
Your vent pipe needs to be unobstructed, and pointing inside the f&e tank, next time you put heating on, go have a look in your loft and watch what happens.

 

[whwend]

Thank you - I can give that a test after work tonight

 

[Madrab]

Is the pumping over an issue in itself

Yes - pumping over can increase corrosion in the system - it can also be indicative of a restricted cold feed or an incorrect pump setting. If it is then it should be investigated.

Or did I perhaps force the system to do it by turning all the radiators off and putting the heating on?

I guess the question there is - why would you do that? Even with all the rads closed though then the system still shouldn't pump over unless there is an issue as suggested above. Do you know if you have a Y plan or S plan or an other?

 

[whwend]

Morning!

When I had system fitted about 20years ago now I wanted the bathroom rad to be on the HW circuit, so it came on more often. I'm not sure how well that was done though because the diverter (?) seems to go to 3 or 4 radiators not just the one, so in the summer I turn all the rads off. Unhelpfully this is sited under carpeted floorboards away from airing cupboard. It was replaced - and the pump about 2 years ago. Not sure what plan I have got, but this diverter has long been bit of an issue and something might be wrong with the 'return aspect. Sorry I am getting to the boundary of my own plumbing understanding now.

I forgot I'd done that and it was stupid cold last weekend so I put the heating on and the noises were abit scary so off it went straight away. I've not tried the heating since, but I'll give it a whirl later


It does sound that if it is pumping over at all I'd better get it looked at. It doesn't look like a pipe leak though or the stain would be probably be getting worse.

 

[Madrab]

it doesn't look like a pipe leak or it the stain would be probably be getting worse

Agreed - leaks rarely fix themselves if there is water behind them.

 

[whwend]

I tested the heating with the radiators 'open' and I didn't get the bangs, knocks, and worrying loud sounds like last time. I attempted to bleed the radiators (no air in there to speak of).
When I got into loft space I did see some water come through that vent pipe. Not much - a couple of tablespoons (twice when I was watching) and not under pressure. I mean like a flow not an exhaust splutter. So I guess the ceiling won't fall in but I should get a plumber to sort out why its pumping water through vent pipe....

 

[terryplumb]

Yes ,get a heating engineer to take a look.