Combi boiler losing pressure

[TonerG1995]

Morning all,

In October 2022 I had a Combi boiler installed in my house. Since then it’s been a bit of a nightmare and the council have been pretty useless in helping.

Soon after having it installed, we found the pressure kept dropping quickly and swiftly found one of our downstairs radiators was leaking sludge so we needed to get that replaced.

Unfortunately that has not remedied the problem. The boiler pressure still drops (not as quickly, but certainly still drops). I’m having to top it up at least once a week and I know this is not normal or even close to being normal.

What I find strange, though, is my water meter isn’t showing continuous running water, none of our rads are leaking and there’s no obvious leaks anywhere else in the house. I would’ve thought, given I’ve had it for over a year now, a mysterious leak would’ve presented itself by now?

Does anyone have any suggestions? I did have a boiler engineer in the house about a month ago and he re pressurised the boiler and, unless I’m misquoting him, said there could be a tiny hairline crack somewhere in the system/pipes letting the pressure out. However the boiler continues to lose pressure despite what he did.

Any help would be really appreciated!

 

[terryplumb]

Water is leaking out, either on the system, pipes/ rads etc, or via the boiler itself.
There should be a pressure relief pipe ,in copper pipe, routed externally. See if any water is dripping from it.

 

[TonerG1995]

Water is leaking out, either on the system, pipes/ rads etc, or via the boiler itself.
There should be a pressure relief pipe ,in copper pipe, routed externally. See if any water is dripping from it.

Sorry to sound really dim, would that be the thick copper pipe they installed that runs along the side of my kitchen into a white box besides my front door? Should I run water/turn the heating on before checking it for leaks?

 

[terryplumb]

I doubt what you describe is the PRV pipe. Show us a pic.
Look for a copper pipe that comes through the wall directly behind the boiler ,and is open ended.

 

[TonerG1995]

I doubt what you describe is the PRV pipe. Show us a pic.
Look for a copper pipe that comes through the wall directly behind the boiler ,and is open ended.

I’ve attached everything I could. The current boiler and its pressure, the piping under the boiler and the only pipe I could find outside the house. It feeds directly into the kitchen and (I’m assuming) the boiler. I couldn’t find any obvious signs of a leak! Apologies for the state of our front garden, we’ve got scaffolding up!

 

[terryplumb]

Look on the external wall that the boiler is mounted on.
The pipe in your pic is probably a gas line.

 

[TonerG1995]

Look on the external wall that the boiler is mounted on.
The pipe in your pic is probably a gas line.

There’s a boiler flue but no other obvious pipes…is there a cause for concern or am I just being dim and missing it?!

 

[terryplumb]

Your being dim !! It's the little stub of pipe sticking out the wall a few feet below the flue !

 

[TonerG1995]

Your being dim !! It's the little stub of pipe sticking out the wall a few feet below the flue !

Hahaha! I just assumed it was the leftovers of old pipe work. It isn’t currently dripping or leaking…however it does look fairly oxidised?

 

[terryplumb]

Tie a plastic bag around it ,to catch any water that comes out. If nothing appears after a few days ,the leak is elsewhere.

 

[TonerG1995]

Tie a plastic bag around it ,to catch any water that comes out. If nothing appears after a few days ,the leak is elsewhere.

Genius. Will do that now and keep you updated. Thanks for your time and patience, by the way. It’s really appreciated.

 

[opps]

I am not a plumber...

The pressure in the system is the pressure of the water in the heating loop. If, for example, one of the copper pipes under the ground floor has a slight leak, you are unlikely to see any evidence of a leak.

The only time your water meter gets involved is when you top up the pressure.

BTW, when the water is hot, the pressure (bar) increases. When trying to compare pressure readings, do so when the heating has not been on for a while.

 

[TonerG1995]

I am not a plumber...

The pressure in the system is the pressure of the water in the heating loop. If, for example, one of the copper pipes under the ground floor has a slight leak, you are unlikely to see any evidence of a leak.

The only time your water meter gets involved is when you top up the pressure.

BTW, when the water is hot, the pressure (bar) increases. When trying to compare pressure readings, do so when the heating has not been on for a while.

That’s interesting, thank you! Say there is a leak in the pipes under the ground floor…I’m assuming that would require a significant amount of invasive work??

 

[foxhole]

What are you setting the pressure at when recharging? ( the setting in photo is ideal) Are you isolating taps on filling loop .

 

[opps]

Tie a plastic bag around it ,to catch any water that comes out. If nothing appears after a few days ,the leak is elsewhere.

Not wanting to hijack this thread. .. but, the house that I am currently painting the exterior of, I have often noticed a pool of water near the pressure release outlet. Given the amount of rain that we have had recently, I cannot tell if it is the PRV, water dripping down from the flue or something else.

However, on several occasions, I have run my hand over the underside of the outlet and it has been slightly wet.

If PRV is letting water out at "regular working" pressures, I guess it needs to be replaced?