Hot water being returned to feed and expansion tank via return pipe

[markp2067]

Good afternoon to you all. Firstly please allow me to apologise if this question has been asked time and time again but i'm baffled, have googled like hell and am now maybe a little confused.

So, Saturday evening i pop out and upon return i notice water dripping from one of the attic overflows. I quick look shows that the F&E tank return(?) pipe is slowly but steadily returning hot water to the tank causing the level to raise and over flow.

A little bit of playing about shows me that when the hot water is switched off on the controller the flow stops with or without the heating being switched on. However as soon as the water heater cycle starts again as does the flow of water.

I have an open vented system with an indirect SS cylinder fitted which has been there for 6 years without a hitch. Nothing has changed in the system for a long time and the issue all of a sudden starts.

Please assist and or advise?

 

[Last Plumber]

You need a Heating Engineer !

there could be many reasons for the problem you have.

I take it you are talking about the vet pipe over the top of the F+E tank?

If you are, there should be no water running from that.

 

[Last Plumber]

You need a Heating Engineer !

there could be many reasons for the problem you have.

I take it you are talking about the vet pipe over the top of the F+E tank?

If you are, there should be no water running from that.

 

[markp2067]

Hi,

Thank you for your reply.

So after speaking with several people and reading umpteen threads regarding similar issues it was decided that the cylinder was in need of replacement. So today we ripped out the old cylinder and fitted a new one. The issues however still persists.

Upon further investigation i can confirm the following -

When heating is off and the hot water cycle is on water comes back up through the expansion pipe. Turn the heating on and it continues to send hot water up the expansion pipe filling the f&e tank.

Turn the water cycle off and it stops, with or with out the heating on.

The mid postioning valve seems to be doing what it should correctly i.e moving up down or central when required to do so, the pump is also working as it should.

I can only think now that its boiler related although that's just an assumption since i know nothing about conventional boilers.

 

[Scott_1979]

did you change the cylinder stat when swapping the cylinder?

 

[john999uk]

If you had called in a heating engineer you may not have had the expense of replacing the hot water cylinder! Without expert knowledge you will be changing things without knowing if it will fix the issue. Plus unless you are Gas safe registered you cant do anything on the boiler!
Best to ask on here for someone local who can do the job for you.
Remember when you get a plumber to do a job you are paying for their training and experience to fix the problem.
Please don't ask someone to visit for a quote so you can find out what the problem is and fix it your self. That would not be fair!!!!

 

[markp2067]

did you change the cylinder stat when swapping the cylinder?

I didn't no. It seems to be clicking in and out as it should this didn't see the sense in changing it.

 

[markp2067]

If you had called in a heating engineer you may not have had the expense of replacing the hot water cylinder! Without expert knowledge you will be changing things without knowing if it will fix the issue. Plus unless you are Gas safe registered you cant do anything on the boiler!
Best to ask on here for someone local who can do the job for you.
Remember when you get a plumber to do a job you are paying for their training and experience to fix the problem.
Please don't ask someone to visit for a quote so you can find out what the problem is and fix it your self. That would not be fair!!!!

Yeah thanks, i'm aware of that. That's the reason i googled like hell and also posted up on here. I spoke with three individual plumbers and the general consensus was a possible fracture in the cylinder coil. Unfortunately we were all wrong.

I will call in a heating specialist and anything boiler related is down to them. I play with water but not gas..... i'm daft but not entirely stupid lol.

 

[john999uk]

Logically thinking about it. If the indirect loop was leaking you would have had to keep topping up the boiler via the fill loop. I would check any mixer taps and mixer shower fittings. If you can isolate them then see if the problem is still there.

 

[heliotrope]

Logically thinking about it. If the indirect loop was leaking you would have had to keep topping up the boiler via the fill loop. I would check any mixer taps and mixer shower fittings. If you can isolate them then see if the problem is still there.

It is an open vent system and it is the F&E tank overflowing.

My money would be on a blocked cold feed. Over pumping would
normally be returned via the cold feed but cannot get past quick
enough so exits the overflow.

Would have been a lot cheaper to clear (still has to be done) than
fitting new cylinder.

 

[KingDoey]

Whats the feed and vent configuration in the airing cupboard look like? Is it high up in a 'H' or air separator? Or is it down low? What speed is pump set to?

 

[markp2067]

It is an open vent system and it is the F&E tank overflowing.

My money would be on a blocked cold feed. Over pumping would
normally be returned via the cold feed but cannot get past quick
enough so exits the overflow.

Would have been a lot cheaper to clear (still has to be done) than
fitting new cylinder.

By cold feed are you referring to the main feed from the mains/fresh water tank? If so then that's most definitely clear as the new cylinder filled up quick enough.

 

[markp2067]

It is an open vent system and it is the F&E tank overflowing.

My money would be on a blocked cold feed. Over pumping would
normally be returned via the cold feed but cannot get past quick
enough so exits the overflow.

Would have been a lot cheaper to clear (still has to be done) than
fitting new cylinder.

By cold feed are you referring to the main feed from the mains/fresh water tank? If so then that's most definitely clear as the new cylinder filled up quick enough.

 

[markp2067]

Whats the feed and vent configuration in the airing cupboard look like? Is it high up in a 'H' or air separator? Or is it down low? What speed is pump set to?

Hi,

The pipe work is high up in a H configuration. The pump is lower down and set on 3 although I have tried setting 2 and it's no different.

 

[heliotrope]

By cold feed are you referring to the main feed from the mains/fresh water tank? If so then that's most definitely clear as the new cylinder filled up quick enough.

The cold feed for the heating system is that whitch is coming out of the bottom of
the small tank that the expansion pipe is overflowing into.

Follow that pipe to where it connects to the heating circuit.

That is where you would be most likely to find any blockage.

This tee would usually need to bee cut out and cleaned/replaced.

 

[markp2067]

Whats the feed and vent configuration in the airing cupboard look like? Is it high up in a 'H' or air separator? Or is it down low? What speed is pump set to?

Duplicated post sorry

 

[markp2067]

The cold feed for the heating system is that whitch is coming out of the bottom of
the small tank that the expansion pipe is overflowing into.

Follow that pipe to where it connects to the heating circuit.

That is where you would be most likely to find any blockage.

This tee would usually need to bee cut out and cleaned/replaced.

I'm with you, thank you. I'm pretty sure that's clear as it refilled fine yester day however it's always worth a look as it may still be restricted.

 

[Chriswareham]

you can check if the header tank feed is blocked by blowing down the expansion pipe if there is resistance and does not come back though the feed to the header tank its blocked if there is little resistance you will see water and gurrgling comeing back it to the tank? thats all there is to it job done ! if there is resistance there is problaby a blockage and you will not be able to fill the rads.as there is no water comeing down from the tank. you could try this firest if its filling there is no blockage!
if the cyliner coil has a leak in it either the header tank or the main tank will ballance out over the corses of the night the header tank is normally higher than the main tank so the ballvalve will be runing very slowthe main tank will get higher and overflow (or vise verser) if the main tank is higher than the header tank.
how ever this will not cause your problam of pumping over the vent!
is the cold feed and vent before the pump or gust the cold feed!
or is the vent comimg off the primary flow to the hot water tank!

 

[aplombier]

Sounds like pump failing , it can't clear the heat away so it's circulating up expansion pipe ,

 

[Chriswareham]

apombier hi mate
he said that it doest pump over on heating so the pump shough be fine only when hot water on whow nows could be pump and boiling over from boiler ifs difficult when not on site

 

[aplombier]

Hi Chris
I agree it's difficult when not on site to diagnose fault, im suspecting pump, it could easily be some clown has played with a gate valve and it hasn't got clear return flow back to boiler, or even sticky diverter valve, one way or another it ain't moving the heat through system so it has to expand and send it over the vent pipe.