Replaced PRV and still leaking

[Mary jones]

the PRV has been replaced twice in the past few months and this seems to cure the leak temporarily, however the leak is now worse and is clearly caused by a different problem. The pressure gauge rises quickly upto 3 bars, (we release the pressure manually) but then when the heating/water is off (boiler not running) it loses pressure to zero whilst it’s off. there is an expansion tank already fitted, this was replaced approx 7 years ago. Does it sound like the expansion tank needs replacing or could it be something else?

 

[Best]

Who fitted the replacement PRVs twice?
You need a heating installer to take a look at it all and also service the boiler, whatever boiler it is.
Note the expansion vessel is supposed to be serviced at each service and certainly will not function properly, if at all, unless it gets checked fairly frequently

 

[Harvest Fields]

the PRV has been replaced twice in the past few months and this seems to cure the leak temporarily, however the leak is now worse and is clearly caused by a different problem. The pressure gauge rises quickly upto 3 bars, (we release the pressure manually) but then when the heating/water is off (boiler not running) it loses pressure to zero whilst it’s off. there is an expansion tank already fitted, this was replaced approx 7 years ago. Does it sound like the expansion tank needs replacing or could it be something else?

When was the last time that the boiler was serviced? This should have been checked on the annual service if I’m honest.

 

[Harvest Fields]

Who fitted the replacement PRVs twice?
You need a heating installer to take a look at it all and also service the boiler, whatever boiler it is.
Note the expansion vessel is supposed to be serviced at each service

Posting at the same time again.

 

[Riley]

First things first is the prv and expansion vessel inside the boiler? What boiler is it?

 

[Mary jones]

Thanks for quick reply
There is an expansion tank next to the boiler, there is another one next to hot water tank, the PRV is also next to hot water tank. It’s a pressurised system.

 

[ShaunCorbs]

Any chance of a pic of the prv ?

 

[Riley]

Agreed pic will help. Sounds like you’re a prv short

 

[Harvest Fields]

Agreed pic will help. Sounds like you’re a prv short

Sounds like it needs a service to me.

 

[Riley]

Well yes but I suspect that OP is confused with regard to Safety devices on an unvented and those on the boiler

 

[Mary jones]

Photo of PRV
It’s a potterton boiler

 

[Riley]

And that is solely on the return pipe on your boiler?? What boiler do you have

 

[ShaunCorbs]

Find the red Red expansion vessel

 

[Mary jones]

This is next to hot water tank
It’s a conventional potterton boiler

 

[Best]

Need full photos showing most of hot cylinder and pipework around it

 

[Riley]

So it’s been changed to a sealed system

 

[Harvest Fields]

I am betting it’s been converted and the PRVs are linked in the airing cupboard

 

[Riley]

Is the boiler with the cylinder

 

[Mary jones]

Photo of pipework hot water tank

 

[Mary jones]

Photo of boiler in garage, hot tank upstairs

 

[ShaunCorbs]

Yep sealed system

Red expansion tank needs looking at best get your boiler service guy to have a look at it

 

[Harvest Fields]

So the PRV in the airing cupboard for the heating, should be attached to or next to the red vessel in the garage. I ask again though. When was it last serviced?

 

[Best]

Cylinder and heating discharge joined to one outlet?
Hard to make it all out

 

[Mary jones]

Thank you for your replies
Just to clarify, it appears to be the red expansion tank? The one next to the boiler that has a problem? Not the one next to tank?

 

[Harvest Fields]

Cylinder and heating discharge joined to one outlet?
Hard to make it all out

That was also my guess above mate.

 

[Harvest Fields]

Thank you for your replies
Just to clarify, it appears to be the red expansion tank? The one next to the boiler that has a problem? Not the one next to tank?

So when was the boiler last serviced?

 

[Mary jones]

Probably service couple of years ago now!

 

[ShaunCorbs]

So the PRV in the airing cupboard for the heating, should be attached to or next to the red vessel in the garage. I ask again though. When was it last serviced?

Doesn’t need to be

 

[Best]

Thank you for your replies
Just to clarify, it appears to be the red expansion tank? The one next to the boiler that has a problem? Not the one next to tank?

How do you know that?
Has it been all serviced?
Has the cylinder also been serviced?

 

[Harvest Fields]

Probably service couple of years ago now!

You need a registered gas safe engineer to service the boiler. Also explain the problem that you are having so that he/she can allow the correct amount of time to sort you out. The vessel needs checking every year.

 

[Harvest Fields]

Doesn’t need to be

Should be as close to the boiler as possible mate (shouldn’t it)

 

[ShaunCorbs]

Should be as close to the boiler as possible mate (shouldn’t it)

Doesn’t matter aslong as there’s no valves on the boiler / between the boiler and prv

 

[Best]

Should be as close to the boiler as possible mate (shouldn’t it)

Ideally, yes, prv close off the heat source.

 

[Best]

Doesn’t matter aslong as there’s no valves on the boiler / between the boiler and prv

I suppose if the pipes from boiler froze in severe weather (highly possible if boiler is in garage or an attic), then a remote prv could end up being isolated and no use

 

[Mary jones]

Thanks for all your replies, I will get some one to take a look

 

[ShaunCorbs]

I suppose if the pipes from boiler froze in severe weather (highly possible if boiler is in garage or an attic), then a remote prv could end up being isolated and no use

Should have a frost stat and that wouldn’t make any difference anyway as unless it’s inside the boiler would be the same

Think of a standard heat only boiler where’s the vent connection / tee normally in the airing cupboard

 

[Harvest Fields]

Thanks for all your replies, I will get some one to take a look

Best option if I’m honest. Ask around for a recommended engineer. I’m inclined to say try a different firm.

 

[Harvest Fields]

Should have a frost stat and that wouldn’t make any difference anyway as unless it’s inside the boiler would be the same

Think of a standard heat only boiler where’s the vent connection / tee normally in the airing cupboard

On this instance though Shaun. It makes no sense to put the PRV where they have when they have fitted the external vessel next to the boiler. They cannot use the excuse of not having an external wall. It’s a garage, it will have at least 1.

 

[Mary jones]

Just one more thing, the boiler has had all components completely replaced, all the PRVs and
The hot water tank expansion vessel have been changed in the last two years.
The only two things that have not been replaced in the past two years is the red expansion vessel next to boiler and the actually hot water tank itself, could it be the hot water tank itself gone wrong?

 

[Harvest Fields]

Just one more thing, the boiler has had all components completely replaced, all the PRVs and
The hot water tank expansion vessel have been changed in the last two years.
The only two things that have not been replaced in the past two years is the red expansion vessel next to boiler and the actually hot water tank itself, could it be the hot water tank itself gone wrong?

Unfortunately we cannot say. You will need an G3 registered engineer to tell you that.

 

[chris watkins]

Yes it could in theory as it is an old enamelled steel type cylinder which I bet has not had the anode replace. If the internal heat exchanger has rusted the higher pressure domestic water could be leaking into the heating water raising the pressure so the heating safety valve discharges at 3bar.
As per other, get a good G3 engineer in (& disconnect that filling loop as per Water Regs).

 

[Harvest Fields]

Yes it could in theory as it is an old enamelled steel type which I bet has not had the anode replace. If the heat exchanger has rusted the higher pressure domestic water could be leaking into the heating water. As per other get a good G3 engineer in (& disconnect that filling loop as per Water Regs).

The pressure in the heating doesn’t rise when off it drops.

 

[Best]

Should have a frost stat and that wouldn’t make any difference anyway as unless it’s inside the boiler would be the same

Think of a standard heat only boiler where’s the vent connection / tee normally in the airing cupboard

I know what you are saying, but even on an open vented system, I always put a prv on the system, - and straight off the boiler pipes. Normally only oil systems, but also some gas.
If an open system feed and vent froze in the attic, the prv would be needed

 

[ShaunCorbs]

I know what you are saying, but even on an open vented system, I always put a prv on the system, - and straight off the boiler pipes. Normally only oil systems, but also some gas.
If an open system feed and vent froze in the attic, the prv would be needed

and if the prv froze

 

[chris watkins]

The pressure in the heating doesn’t rise when off it drops.

Safety valve is leaking all the time?
Sorry I will go back & read all the posts.

 

[Burger]

Just one more thing, the boiler has had all components completely replaced, all the PRVs and
The hot water tank expansion vessel have been changed in the last two years.
The only two things that have not been replaced in the past two years is the red expansion vessel next to boiler and the actually hot water tank itself, could it be the hot water tank itself gone wrong?

Everything points to getting it checked out by a gas safe heating engineer, and perhaps a different one/firm who replaced the prvs. The parts have been replaced in the last 2 years but it doesn’t mean they don’t require checking - as per previous posts every service.

 

[Best]

and if the prv froze

Then there would be no open pipe safety left.
But the boiler can likely be the last system area to freeze. Pipes leaving it in a garage are usually more vulnerable to freezing first, as would vent and feed in some roofspaces.
As you said, frost stat should save the boiler

 

[MHG]

Expansion vessel requires recharging or replacing

 

[David turner]

the PRV has been replaced twice in the past few months and this seems to cure the leak temporarily, however the leak is now worse and is clearly caused by a different problem. The pressure gauge rises quickly upto 3 bars, (we release the pressure manually) but then when the heating/water is off (boiler not running) it loses pressure to zero whilst it’s off. there is an expansion tank already fitted, this was replaced approx 7 years ago. Does it sound like the expansion tank needs replacing or could it be something else?

 

[David turner]

Your vessel requires charging or replacing if it won’t hold pressure also is the vessel large enough for amount of radiators that you have in property common problem is that plumbers don’t size up system correctly and fit undersized vessel additional vessel might be the answer to your problems.