Boiler over pressurised

[Matt0029]

I went to a boiler the customer had over pressurised it by leaving the filling loop on high cold mains at 10 bar, and water was leaking out of the boiler expansion vessel. On the metal seal it's ok when the pressure reduced to 1bar. I presume will need a new vessel though. Anyone come across this before? Was leaking on the joint. Thanks

 

[ShaunCorbs]

Yep bladder gone internally

 

[Deleted member 120897]

Yep, come across this a handful of times, I always replace the vessel, although had it once, recharged and it was ok, but still changed it.

 

[EvilDrPorkChop]

I've had two that were leaking and i've recharged and both had been fine afterwards, not sure how that one works like 😂

 

[Matt0029]

Thanks it only did it when the system was pressurised to 10 bar though. Pressed the valve had air in. Could it be the high pressure that caused the issue?

 

[Matt0029]

I've had two that were leaking and i've recharged and both had been fine afterwards, not sure how that one works like 😂

Leaking from the actual metal casing?

 

[Scott_D]

How did it get to 10 bar??
Prv not working?

 

[Matt0029]

Boiler pressure was at above 4bar on top of gauge. Know we have around 10 bar around here. The prv wasn't operating though it did when I operated it to reduce the pressure. Couldn't through filing loop as they have put the check valve on the wrong side. The heating return. The prv is installed to totally run vertically up hill boiler is in the cellar. Condensate is pumped.

 

[EvilDrPorkChop]

Leaking from the actual metal casing?

Yeah. One on a Heatline. That lasted 2 1/2 years before I replaced the boiler. Another on a Ferroli that's still going!

 

[EvilDrPorkChop]

Boiler pressure was at above 4bar on top of gauge. Know we have around 10 bar around here. The prv wasn't operating though it did when I operated it to reduce the pressure. Couldn't through filing loop as they have put the check valve on the wrong side. The heating return. The prv is installed to totally run vertically up hill boiler is in the cellar. Condensate is pumped.

Think your PRV would have been passing, especially at 4 bar. If you had 10 bar in the system you'd of had a rad split or the expansion blow!

 

[Matt0029]

Did it leak because if high pressure or because of the diaphragm losing its charge?

 

[Deleted member 120897]

Think your PRV would have been passing, especially at 4 bar. If you had 10 bar in the system you'd of had a rad split or the expansion blow!

I don’t dispute the 10 bar, but if the failed vessel was leaking - would the prv still operate?

 

[EvilDrPorkChop]

I don’t dispute the 10 bar, but if the failed vessel was leaking - would the prv still operate?

Yeah, it's obviously not worked properly at 3 bar like it should of, and blown off fully. But I bet it was passing. Also the pressure gauge could have been reading incorrect, there's that possibility too.

 

[Matt0029]

Thanks they had just left the filling loop open mains pressure freely going in. I couldn't hear it discharging.

 

[Matt0029]

Why would water make it thought the casing at a higher pressure but ok when lowered to normal operating pressure?

 

[Matt0029]

It's a remeha avanta plus 35c not worked on these before. Had the red light on the flow sensor for the hot water so presume there related to baxi?

 

[Matt0029]

Yep bladder gone internally

I thought that but when I pressed the shrider valve it released air. Was expecting water if the bladder had gone.

 

[Deleted member 120897]

It's a remeha avanta plus 35c not worked on these before. Had the red light on the flow sensor for the hot water so presume there related to baxi?

Yeah, BDR thermea group (Baxi/potterton/main/remeha to name a few)

 

[Matt0029]

Yeah. One on a Heatline. That lasted 2 1/2 years before I replaced the boiler. Another on a Ferroli that's still going!

Did you repressure the vessel to stop the leak? This literally stopped when I de- pressurised the system.

 

[Matt0029]

Boiler did look abit in neglect the auto air vent on the out casing for the main hex appeared shut. As looked to have leaked in the past.

 

[ShaunCorbs]

expansion vesslse dont have a fully bladder its a rubber sheet in the middle with air one side and water the other and the crimp is the thing that holds the rubber in

 

[ShaunCorbs]

eg

 

[Matt0029]

Thanks so possible the pressure got so high water made its way out of the crimp?

 

[ShaunCorbs]

Yep

 

[Matt0029]

Do you think it maybe ok now the pressure is at normal. It seemed ok. Is a 12 year old boiler. Not sure warrants spending too much on.

 

[Matt0029]

Went to look for a favour.

 

[Matt0029]

Seems to be wanting a cold fill pressure of 2 bar which seems abit high?