Expansion vessel in Gravity feed system-Advice needed please

[galegp]

Hi all,

I just need some advice in the following topic – expansion vessel.

My house is plumbed using a gravity system (with the usual water tank in the attic and water). Talking to my usual plumber the other guy who suggested to perhaps put a expansion vessel in the attic replacing the existing (small) cold water tank. He thinks that could help the radiator give better output and improve the efficiency of the central heating system.

What are your thoughts in the above topic?

Thanks in advance for the replies and Merry Xmas.

 

[45yearsagasman]

30+ views and still not an answer to this baffling problem.

 

[PeedOftec]

Why does he think it will? What are his reasons? The size of tank will not affect the pressure in the system unless the water level is increased, then you may as well just lift the small tank higher.

It is a common misconception the bigger the loft tank the greater the pressure in the system below. Same water level.... same pressure... simplz.

PS.. mine is the same type of system.

 

[ChrisR]

The tank you've got in the attic now IS an expansion tank.
Sure he didn't say Expansion VESSEL? That would mean he wanted to pressurise the system. That can make a small difference, but not much, it just helps get air out quicker really - so if you had a (bad) system generating a lot of air then maybe ....

First thing you should do is "balance" your system.

 

[galegp]

The tank you've got in the attic now IS an expansion tank.
Sure he didn't say Expansion VESSEL? That would mean he wanted to pressurise the system. That can make a small difference, but not much, it just helps get air out quicker really - so if you had a (bad) system generating a lot of air then maybe ....

First thing you should do is "balance" your system.

Yes yes he said an expansion vessel. Sorry I actually confused the names.
The system gets a fair bit of air so I wonder if it is worthy to spend the many in the expansion vessel.

He did balance the system for me already.

 

[Norcon]

How much air?
Are you bleeding every day? Or once a year say?

 

[galegp]

How much air?
Are you bleeding every day? Or once a year say?

I used to bleed daily and then turned out I had a leak in system. Plumber put some leak sealer and since then it has seemed OK. I haven't had to bleed any radiator yet.

How often would you call it "time to fit a vessel"?

I have noticed two neighbours in my street seem to have one fitted so there is a chance the cowboy builders did a quick job in these houses.

 

[Norcon]

If it ain't broken then don't fix it.

 

[ChrisR]

Sort out the "leak" first. Could be corroding, which causes accumulation of corrosion gases. Sludge, etc etc....
Old system, mix of a couple of "issues"...

 

[galegp]

In a different note. I have zone the water from the heating. The only thing is that when heating the radiators, boiler only heats the water in the cylinder.

In my system, is there a way to heat radiators without heating the water in the cylinder?

Thanks,
David

 

[JohnHarrison]

Is it pumping over? If so then a One pipe feed and expansion tank may be the answer. A one pipe, 22mm, leaves the bottom of the tank. The boiler needs a high limit thermostat on the boiler. It is best to put an ant-circulation loop in the feed/expansion pipe. The circulation moves water oxygenated water from the tank to the main body of the system, meaning the water does not mix. This reduces the speed the water is being oxygenated, or maybe eliminate it.