Central heating pressure loss.

Do-more

House is about 5 years old with a closed central heating system (no header tank).

A couple of months ago I noticed that the pressure gauge above the pressure vessel had dropped a bit. I've pumped up the pressure in the vessel a few times since. Pressure gauge is now dropping to zero within a week.

There is no obvious signs of a leak in the system, I've inspected all the TRV valves and the circulation pump in the enclosure by the boiler and there are no signs of water leaking.

Some one suggested that I tighten up all the TRV valves, but I'm wary of causing more problems than I'll solve.

Before I do anything is there any advice on what I should do? Is there anything that I can apply to the TRV's to act as a "telltale" for a leak?

Cheers D-M.

ircoha

there are folks on this forum much more qualified on this than moi, but can u see the flue gases when system is on: maybe there is a hole in ur boiler and u should see loads of water vapour spewing out the flue pipe.

there is stuff eg http://www.screwfix.com/app/sfd/cat/pro.jsp?id=65161

u can stick into the system to plug a leak: I am not a fan till i know what the leak is:

311

Do-more wrote:

House is about 5 years old with a closed central heating system (no header tank).

A couple of months ago I noticed that the pressure gauge above the pressure vessel had dropped a bit. I've pumped up the pressure in the vessel a few times since. Pressure gauge is now dropping to zero within a week.

There is no obvious signs of a leak in the system, I've inspected all the TRV valves and the circulation pump in the enclosure by the boiler and there are no signs of water leaking.

Some one suggested that I tighten up all the TRV valves, but I'm wary of causing more problems than I'll solve.

Before I do anything is there any advice on what I should do? Is there anything that I can apply to the TRV's to act as a "telltale" for a leak?

Cheers D-M.

Why did you decide the guage was a reading of the vesell?

Do-more

_Brian_ wrote:

Why did you decide the guage was a reading of the vesell?

Because when I pump up the pressure in the vessel the gauge goes up!

311

I'm afraid that the guage has nothing to do with the vessel.

You've probably damage the diaphragm inside:(

Do-more

Oops!

Don't know if this is related or a seperate issue, but when I was checking the pump for leaks I noticed that the two valves in the picture are showing signs of considerable leaks...

311

That looks like a firebird boiler ,judging by the fittings it's only a couple of years old.

Seems a bit strange that you should be having this type of trouble so soon.
Was the boiler fit onto the original system ,did they do any work up in the hot press?

Do-more

_Brian_ wrote:

That looks like a firebird boiler ,judging by the fittings it's only a couple of years old.

Seems a bit strange that you should be having this type of trouble so soon.
Was the boiler fit onto the original system ,did they do any work up in the hot press?

House, heating system and boiler are all about 5 years old, boiler was last serviced in November '06.

Have had trouble with the Peglar TRV valves sticking, particularly at this time of year after the heating has been off for the summer, but other than that no particular problems before this.

What do you advise?

311

In all honesty ,I'd get it checked out and determine whether or not your vessel is bust.

Then try and find out where your pressure is going ,i.e leak. It might well be just the safety valve is passing.

Do-more

Cheers Brian - at least I'm fore-armed for dealing with the plumber now.

beldin

That looks like the pressure release valve (the one with the red cap). That is designed to release water out of the system if the pressure goes too high. That should have a pipe leading to the outside world.
The problem with them is that if the open once then they might not close properly and so be leaking under pressure.
To get your pressure high again you have to fill the system up again with water, there should be a filling loop somewhere coming from the mains water. The pressure on the gauge should be about 1 bar.

The other valve is for getting rid of excess air in the system , air bleeds out of the top of it.

JamesM

As beldin says, you have not mentioned trying to fill the system - pumping the pressure vessel only raised the pressure for a short time. You have to find the valve, probably in the hotpress, and fill the system - you may also have damaged the diaphragm in the pressure vessel. The water escaping from the release valve may be because the diaphragm is burst and cannot take the expansion. If you tap the pressure vessel, the side with air in it will have a lighter sound than the side with water (the diaphragm is in the middle). If they both sound dull, it is likely that the diaphragm is gone.
Jim.

Do-more

Thanks for all the feedback guys.

I've had a plumber round and it turned out that the valve which is supposed to automatically keep the system topped up with water was stuck shut. It's been replaced and system pressure is showing as normal now. Diaphragm was intact!

Hopefully thats the extent of the problem (fingers crossed!).

Thanks again.

D-M.