Leaky boiler.

[Bryan Williams]

Evening,

Just moved house and noticed tonight that the boiler is leaking.
It's a Worcester Bosch Greenstar 241 junior combi mk 3.
Moved in a couple of days ago and turned it on that day, I noticed that the pressure was on zero so I opened the top up tap and it shot up to 3 so I shut the tap.
It seemed to work OK, the pressure crept up a little then stayed about 3 1/2,I know that's a bit high.
Bled all the rads.
It seemed to work ok.
Turned off the boiler bedtime.
Next day the pressure was on zero again.
I turned the boiler on to 3 and within 5mins it was up to 3bar pressure, I assumed that this was just the way it worked.

I did notice that the house water pressure was low so I turned the stop cock on fully today and go a bit more flow through the taps.
Just noticed this evening a drip from the bottom left of the boiler on turning it on.
Quite a bit at first but then slowed down to a couple of drips a minute.
The pressure has only gone up to just over 1 this time.
Turned it off now.
There's a guy on YouTube who strips this very boiler down and shows the various bits that fail,there's a lot, he's not a big fan of WB, thinks they're overrated.
It looks like one of the faults he has pointed out, a cracked/pinholed pipe to the bottom left and back.
Anyway, I'll get it done, but can I use it if I top the pressure up first or will it just complicate things.
Also, nearly forgot, there is no programmer/timer with it as far as I can tell, none on wall or boiler, just a weird box right next to the boiler. See pics.
The new place is a 3 bed bungalow so the boiler was probably adequate when installed, but it seems the only control is the temp knob and eco button.
Cheers.

 

[brightspark]

the box is a wireless transmitter someone must have taken the portable reciever with them which controls the timer and room temperature . a decent one is about 80 quid up over dont buy a cheap salus one there krap . boilers are normally pressurized to 1 and a half bar when cold cant help with the leak though

 

[knighty]

look on top of it for what looks like a tyre air valve - most I've seen stick out the top so are easy to get to

that's for the expansion vessel, it should be at about 80% system pressure so about 1.2bar if you want to run at 1.5bar

check the pressure in it, if it's low blow it up to 1.2bar, see if the system holds pressure any longer

 

[Tigman]

If you pressurised to 3 bar and turned on , the pressure creeps up and would have lifted the pressure relief valve ,correct me if I'm wrong they are usually set to 3 bar lift ! The leak may be the discharge pipe is not connected properly ? Once the relief valve has discharged it sometimes doesn't reseat properly carry on dripping !

 

[gaz1]

your expansion tank is faulty best to buy an external one and fit there easy enough to do

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the pressure it needs is between 1bar-to 2 marks above the 1 bar pressure otherwise it jets out the prv valve

which you might need as well as they do go faulty as they are sending over pressure out the system often

 

[Neilj]

^^^^^ what @Tigman said.
If the boiler pressure rises drastically when it gets warm then the expansion vessel is not doing it's job, so it either needs recharging or it's failed. Relief valve is normally set at 3 bar and once they've popped they have a habit of not reseating properly. Note the discharge from the relief valve should be routed outside to a safe location but maybe it's not been piped up and it's just dripping out of an open pipe inside / below the boiler. Can you see where the water is coming from?
As long as you keep the system pressurised then you're not going to do any harm running it the way it is, but if it is a pinholed pipe then prepare yourself for it to get worse!

 

[Kayos]

Expansion vessel has gone

Boiler off the wall to swap as it lives in the mounting jig

Fit an external one

 

[Bryan Williams]

look on top of it for what looks like a tyre air valve - most I've seen stick out the top so are easy to get to

that's for the expansion vessel, it should be at about 80% system pressure so about 1.2bar if you want to run at 1.5bar

check the pressure in it, if it's low blow it up to 1.2bar, see if the system holds pressure any longer

 

[Bryan Williams]

Just played with it again, after leaving it off for half hour the pressure was on zero, I opened the loop valve and brought it up to 1.5bar and shut the loop.
Turned it on set at temp 3, the pressure crept to 2.5 so I turned the temp down to 1 and the pressure dropped to 2 and seemed to settle, turned the temp up to 2 and the pressure crept to 2.5 again. What's the best way to relieve the pressure, bleed a rad or can I use the drain on the bottom pipe in pic?
Turned

 

[Bryan Williams]

 

[Bryan Williams]

Also found the schrader valve but my pump is in my van at the old house in Oldham, I'm in Southport...

 

[gaz1]

bleed it through your rads

you dont want to touch that until needed and when your fitting the new parts on the system

 

[Kayos]

I'd just bleed a rad

I would also put money on the vessel being failed and not being able to pump it up

 

[Bryan Williams]

Expansion vessel has gone

Boiler off the wall to swap as it lives in the mounting jig

Fit an external one

Thought you had to have a Corgi?

 

[Kayos]

Thought you had to have a Corgi?

Gas Safe and yes, to remove the boiler from the jig you most definitely do, given the age of the boiler something will break and isn't worth it

Fitting an additional expansion vessel on the system however does not require Gas Safe registration

 

[brightspark]

Thought you had to have a Corgi?

just replaced the fan on my boiler got a reconditioned one 80 quid wasnt going to buy a new one for 185 quid and pay probably about 80 quid to have it fitted. 4 screws and a couple of nuts and 20 minutes to fit and its now working fine

 

[Neilj]

Anything that breaks into the combustion chamber needs a Gas Safe engineer. Depends on the boiler construction as to whether getting to the expansion vessel is deemed breaching the combustion chamber or not, on some designs removing the front panel breaches it, on others it's not an issue. I've no idea on the WB designs to be honest but as @Kayos says, an external one can be fitted by anyone, assuming a bit of general plumbing knowledge.
If you're precharging to 1.5 bar cold and it gets over 2.5 bar warm then it's definitely not functioning.

 

[Kayos]

Anything that breaks into the combustion chamber needs a Gas Safe engineer. Depends on the boiler construction as to whether getting to the expansion vessel is deemed breaching the combustion chamber or not, on some designs removing the front panel breaches it, on others it's not an issue. I've no idea on the WB designs to be honest but as @Kayos says, an external one can be fitted by anyone, assuming a bit of general plumbing knowledge.
If you're precharging to 1.5 bar cold and it gets over 2.5 bar warm then it's definitely not functioning.

Having fitted hundreds of those boilers, I can confirm they need removing from the jig, this includes removing the flue and disconnecting the gas

Definitely needs a gas Safe engineer

 

[Neilj]

Also, drop pressure by bleeding a rad. That drain valve under the boiler will have a rubber disk in it and it will be rock hard with all the heat. Almost guaranteed to fall apart / not reseal when you undo it!

 

[Neilj]

Having fitted hundreds of those boilers, I can confirm they need removing from the jig, this includes removing the flue and disconnecting the gas

Definitely needs a gas Safe engineer

There speaks a man with knowledge (unlike me!). I'd definitely be fitting an external one in that case if it were me.