Central Heating Over Flow Issue that's stumped many heating engineers :(

drummer_666

My overflow pipe from the cylinder is constantly flowing.

So much that when I got back from my travels my lounge wall is wet internally. I was away two months but had a lodger living here using hot water/heating etc.

I have a cylinder in the loft (fitted 1.5 years ago same time as new Ariston boiler). It's a cylinder and above it ONE cold water tank.

I've had two heating engineer/plumbers out including the guys who fitted the system and they are stumped and have given up.

The valve has been replaced and it's closing off properly.
The thermostat works ok.
Boiler pressure drops sometimes, maybe needs topping up every couple of months.

When the guys were here they drained water, adjusted water level, it remained steady and not overflowing whilst they were here, and for the rest of the day. Come morning the overflow pipe was flowing water again.

Does anyone have any ideas what it can be?

I intended to have my house for sale last week, but need this problem rectified first... and then hire a dehumidifier to dry out the patch on my wall.

Thank you

southcoastrgi

is it the overflow from the roof tank ?
is it a normal vented cylinder ?
model of the boiler ?

booty40uk

Any chance of some pics? Is it vented or invented cylinder?

Slowly_does_it..

2 very quick items : Are you sure it is your heating that is overflowing? - My toilet overflows if not flushed for about 3 or 4 weeks, and that overflow is very close to one heating overflow pipe.

Some mains water pressures increase overnight when fewer people in the area are running baths / showers etc, so this might be pushing water into your system during those hours.

dee4life2005

cold water tank overflow ?

drummer_666

Sorry for delay

Yes it's the cold water tank over flowing

The problem seemed to start all of a sudden. It was all fine for over a year

Ariston Clas HE 24 System Boiler

I'm not sure if unvented/vented - but the installer said the cold water tank would be just about warm because of the type of system it is, if this helps?

I will get some photos later but I have another guy looking at it at the moment

drummer_666

ok third guy couldn't see what it is.

He said valve is closing off properly, water wasnt entering whilst he was there (same as with other two guys), even with hot water on max etc.

He mentioned perhaps cold from a mixer tap is getting into the hot water, he's going to read up on it and said call him if it happens again - and I guarantee it will be happening again by morning latest.

southcoastrgi

of course they can't see it because as usual you are employing muppets
yes it could be a mixer tap or a shower valve causing the prob

just some things i can see from that pic

the pipe lagging isn't thick enough
the supply to the CWS tank should have a stop tap on it not a gate valve
the bottom of the CWS tank should be a min of 1m above the outlet of the cylinder
the flow from the boiler should go into the top connection on the cylinder coil not the bottom one so it's piped wrong
that cls timber they have made the frame out of isn't strong enough & it's not braced with cross beams to stop it moving

drummer_666

How am I supposed to find people that aren't muppets? So many of them seem to be, even though have good reviews etc

Nice to reconfirm I won't be using the same engineers/plumbing company again on my next house!

Just off the phone to my dad, realised we changed the valve on shower in Jan 8th - noticed problem by 24th Jan

So hopefully this is the problem.

My dad is just guessing but says can prob fit a 1 way valve into the pipe from behind the bath panel without removing any tiles... but he isn't an expert

southcoastrgi

when you move house send me a pm with the area you are & i'll get you a decent installer, a check valve on the hot to the shower should hopefully sort the prob

drummer_666

southcoastrgi wrote: »

when you move house send me a pm with the area you are & i'll get you a decent installer, a check valve on the hot to the shower should hopefully sort the prob

Fingers crossed... One question - I haven't used that shower in a couple of days, does it need to be used to cause the problem?

Hopefully next place won't need so much doing to it in terms of heating/water, but thank you for the offer and I'll def do that if I do need an installer again

Got a decent plasterer and now know a spark, so things are getting better lol