Water flowing through vent pipe over F&E tank.

[Telboy24]

I recently took off an end stop on the vent/expansion pipe over the heating header tank. I now know why it was capped off. When the 2 way valve opens to heat the hot water, water pours out of the vent pipe. I had a heating engineer out, he said get rid, open vented systems are now obsolete, failing that, cap off the pipe again. That great 2minute advise cost me £40. So, I've checked a lot of advice on here, and firstly the whole system is 22mm pipework, except for the vent pipe which is 15mm, should this be 22mm as well. The cold feed goes to the top of the heating coil in the HW tank comes out at the bottom 2metres of pipework, then a tee to the vent pipe, then the 2 way valve. Then I guess, to the boiler in a detached garage with hidden pipework, a nightmare to chase. I can't find anywhere with this layout of feed and vent and wonder if anyone has any advice as I can't afford a new boiler and sealed system. My boiler does have an overheat thermostat, so the blocked vent is probably not dangerous.

 

[exedon2]

Some clear pictures of what you have and a sketch of pipework layout would be useful.
Vent pipes should be 22mm and never ever capped!

 

[Telboy24]

Some clear pictures of what you have and a sketch of pipework layout would be useful.
Vent pipes should be 22mm and never ever capped!

Photo to follow, there is very little of visible pipework to photograph, but I'll photo what I have. Thanks for your reply

 

[Telboy24]

Photo to follow, there is very little of visible pipework to photograph, but I'll photo what I have. Thanks for your reply

 

[ShaunCorbs]

Old gravity set up the heating system needs sealing / pressurising

 

[Telboy24]

Old gravity set up the heating system needs sealing / pressurising

I'm not a plumber or heating engineer, I don't know what you mean by sealing. Does that mean it's OK to close off the vent pipe, which would mean effectively it's sealed.

 

[ShaunCorbs]

No need a heating engineer to seal the system for you eg expansion vessel filling loop etc

 

[Telboy24]

Old gravity set up the heating system needs sealing / pressurising

I'm not a plumber or heating engineer, I don't know what you mean by sealing. Does that mean it's OK to close off the vent pipe, which would mean effectively it's sealed

No need a heating engineer to seal the system for you eg expansion vessel filling loop etc

So, sorry for my ignorance, but how has it operated all these years as it stands. It all works fine unless I take that end stop off what I thought was the vent.

 

[ShaunCorbs]

I'm not a plumber or heating engineer, I don't know what you mean by sealing. Does that mean it's OK to close off the vent pipe, which would mean effectively it's sealed

So, sorry for my ignorance, but how has it operated all these years as it stands. It all works fine unless I take that end stop off what I thought was the vent.

It still expands through the feed so the tank water still rises so needs sorting

 

[Telboy24]

It still expands through the feed so the tank water still rises so needs sorting

 

[Telboy24]

But that would cause the f&e tank to overflow wouldn't it? That's never happened. The water level stays the same.

 

[ShaunCorbs]

But that would cause the f&e tank to overflow wouldn't it? That's never happened. The water level stays the same.

No as when it stops the water flows back in

 

[Telboy24]

No as when it stops the water flows back in

OK thanks. I'll try and find an engineer that can help me.

 

[andyburke]

Hi maybe a bit late but check speed on central heating pump if on 3 turn down to 1 or 2 if the pump is to fast it creates over pumping and will cause oxygen to in system and create rust

 

[John.g]

If the cold feed is 22mm and has .no isolation valve then a vent is not required as far as I know.