Boiler losing pressure. Leaks?

Picaresque

Hi
My boiler has been losing pressure for the past few months.
I keep topping up every week or 2 to bring it back to 1.5 bars.

My plumber came and said that I may have a leak in the system.
I have a mix of copper and gun barrel pipes all over the house, downstairs and upstairs.

My system has 3 zones. downstairs, upstairs and hot water.
I have noticed that one of the rads upstairs is always the one affected but I do not see any stain on the ceiling below.

Worst case scenario would be to open up the wooden floors (laminated + old floors) downstairs where I think most of the gun barrel are running.

Are boilers losing pressure always a sign of leaks?

Is there any way to identify a specific area? If I only run one zone out of the threes, but the pressure does not drop, can it help me to identify the zone affected?

Thanks !

Exp271

pretty much its always a leak yes.

Picaresque

Thanks.
Silly question but in the case of a zoned system, should all the zones be opened when topping up?
I have Google Nest but I guess it would require the boiler to be one to have them opened or can it be done manually at the automatic valves?

Oscar_Madison

I had low pressure about a year ago- wasn’t a leak - some part in the hotpress needed replacing - some sort of regulator maybe? Made sense at the time but just can’t recall right now - fitted and fixed relatively quickly - just to put another perspective on things - hopefully won’t be too damaging or expensive for you

Lenar3556

https://www.boards.ie/discussion/2058351030/boiler-losing-pressure-leaks

A failed expansion vessel is another possibility and would be worth checking in the first instance.

If there is a genuine leak, Tec7 Plumb is an effective leak sealer which is worth a try. You just add it to the central heating system and it reacts with the atmosphere at the point of the leak in an attempt to seal it. There are no guarantees, but it’s non invasive and worth a shot.

Exp271

https://www.boards.ie/discussion/comment/122117596#Comment_122117596

expansion vessel

stephenmarr

leak in coil of cylinder another possibility

TheDriver

Both my pressure losses were leaking motorised valves. One wouldn't be noticed as it was leaking down behind the press.

Kaisr Sose

If there is no evidence of a leak from rads or pipes look at the boiler.

A cup of water lost over a few days will bring you below operating pressure

In order of least expensive

• Faulty safety valve
• Faulty expansion vessel

Both are possibilities and the former is a common cause of boilwr pressure loss. Are you able to see or can you check if there is water dripping from the discharge pipe?

I am not a plumber but in my home the cause of pressure loss of about .5bar over 10 day was the safety valve.

Picaresque

Thanks, interesting enough, I do not have an expansion vessel.

Oscar_Madison

https://www.boards.ie/discussion/comment/122118116#Comment_122118116

thank you sir/madame- that’s the one

Clo-Clo

I had this years ago in another house, in end found a tiny leak at a joint under the stairs and it just needed to get tightened, pain in ass to find

monkeybutter

https://www.boards.ie/discussion/2058351030/boiler-losing-pressure-leaks

you can buy a leak sealer…….

Picaresque

https://www.boards.ie/discussion/comment/122120090#Comment_122120090

Does it work with gunbarrel pipes too?

monkeybutter

https://www.boards.ie/discussion/comment/122125410#Comment_122125410

Would assume so

Media999

I just used the leak sealer after this exact problem. Straight into the highest radiator after draining it. Haven’t had a problem since.

If you regularly top up the water it actually rusts the inside which in turn causes more problems. Mine started rusting around the new radiator inlets and outlets. Strangely the old radiators didn’t.

In future I’ll do it a lot quicker but I’d advise you do it asap as the top up water causes more issues.

Dublin City Handyman

I didnI didn't read all the comments... sounds like a leek... And it's probably under the Concrete floor downstairs because it's not showing up on the ceilings above… A