F&E tank in the loft

[Hazelb]

ok forgive my ignorance.........

I was up in the loft the other day and noticed when the boiler and pump sprang into life......so did the feed and expansion tank in the loft!

Is it supposed to do this?

What I mean is that will the boiler/pump running water was merrily coming out the expansion pipe at a reasonable rate.

The pump it just on the floor below the tank and the expansion pipe riser tee's off pipework quite close to the pump.

 

[bengasman]

Chances are the system is full of crud due to lack of proper maintenance, which means it needs cleaning.

 

[D_Hailsham]

The pump it just on the floor below the tank and the expansion pipe riser tee's off pipework quite close to the pump.

What is the vertical distance between the water level in the tank and the pump inlet?

 

[Hazelb]

The system was power flushed about 5 years ago.

The distance between pump inlet and and tank water level is about 4m

 

[D_Hailsham]

The distance between pump inlet and and tank water level is about 4m

Thanks for the answer. Just realized that I had misinterpreted your description of where the pump is. I took "on the floor below the tank" literally, i.e the pump was lying on the floor under the tank - a distance of maybe 50cm.

Back to your problem.

What speed is the pump set to?
Which make/model boiler do you have?

 

[digdilem]

I was up in the loft the other day and noticed when the boiler and pump sprang into life......so did the feed and expansion tank in the loft!

Is it supposed to do this?

As you've probably guessed from the other replies - definitely not!

It could be too fast/big a pump, crud as suggested, or every radiator has a TRV which is shut down - all leading to higher pressure. It's entirely possible there's a more significant fault elsewhere or even that the system is badly designed.

The most should should expect is a few drips as the water mass expands as it heats up. In many (most?) systems you don't even get that. Something's gone wrong and this is functioning as a safety valve.

Does need fixing as this will:

A) Introduce oxygen leading to much increased corrosion in your heating system.

B) Release moist air into an unheated space (roof) leading to significant condensation problems and ultimately timber rot and damp.


Why was it power flushed, and did that fix the problem it was intended to?

 

[45yearsagasman]

After all that,from my experience you will find a restriction near the cold feed/open vent connections into your system.Using a magnet,run it along the copper pipes and it will stick to any copper that contains iron magnetite and thats where your problem will be.Start with the simple things first, after all,it worked ok once.

 

[Nige F]

After all that,it worked ok once.

so did the Titanic

 

[Hazelb]

After all that,from my experience you will find a restriction near the cold feed/open vent connections into your system.Using a magnet,run it along the copper pipes and it will stick to any copper that contains iron magnetite and thats where your problem will be.Start with the simple things first, after all,it worked ok once.

From this I think you mean the 'restriction' is in the circulating pipework, forcing water up the vent pipe?

 

[Hazelb]

To be honest the whole heating system is approaching melt down!

I used to do the plumbing stuff myself and understood the system fairly well, then we had an extension built and the plumbing that was put in didn't work well.

So I got plumbers in to fix it.....oh dear!

They put the large room (in the extension) on its own heating circuit (with dedicated room stat ). Changing the existing system from a 3-port valve system to one with two heating zones and a HW tank (each with a 2 port valve ).

I don't have a lot of confidence in their work. They ran the pipework for an extra radiator that was needed through an unheated garage (are you supposed to do that? ) and plumbed in a shower (hot and cold wrong way round ).

They didn't give me a new two zone heating controller, but a separate 'heating only' one for the new circuit and a wireless room stat ( that has long since been binned! and replace with a wired one)


Sometimes the boiler kettles very badly sometimes.......and I'm starting to suspect a 'pump over-run' hasn't been connected properly.

Now the original controller seems a bit flaky.....sometimes the heating circuit only comes on if the HW is on!

To be honest it's all a bit of a mess.......and I can't do much about it in the winter.....or before the lodger moves out!

 

[bengasman]

To be honest the whole heating system is approaching melt down!

I used to do the plumbing stuff myself and understood the system fairly well, ...

If that is the case, how come you are a regular poster here with problems and think your system approaches melt down?

 

[Axel]

After all that,it worked ok once.

so did the Titanic

Wrong. It sunk on its maiden voyage, therefore failing to successfully perform its task even once.

 

[barkie1]

Changing the existing system from a 3-port valve system to one with two heating zones and a HW tank (each with a 2 port valve ).

This might be becuse heating should be zoned at so that each zone heats a maximum area of 100m2 i think.. dont know how big your extention is nor am i defending the plumbers.

Kettling could be due to the constant venting pulling in air causing air locks? might be worth having a think at changing the system in to a presurised system?

just some thoughts

 

[Hazelb]

Changing the existing system from a 3-port valve system to one with two heating zones and a HW tank (each with a 2 port valve ).

This might be because heating should be zoned at so that each zone heats a maximum area of 100m2 i think.. dont know how big your extention is nor am i defending the plumbers.

Kettling could be due to the constant venting pulling in air causing air locks? might be worth having a think at changing the system in to a presurised system?

just some thoughts

The zoning is fine and means the extension now keeps well controlled at an even temp.

I'll check for any obvious restrictions in the pipe work and then start saving for a bit of a system overhaul in the summer months. ( not by me)

It may be time for a boiler change anyway.

 

[digdilem]

They ran the pipework for an extra radiator that was needed through an unheated garage (are you supposed to do that? )

Provided it's well lagged, not a problem and sometimes unavoidable. I have a system where one zone is supplied by pipes running some 25m through an unheated space.

and plumbed in a shower (hot and cold wrong way round ).

Alas, I can't defend that one.