Leaky boiler.

[badabec]

Fancy having a notice 'Do not press this button'!

 

[Bryan Williams]

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

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

So you cannot fit an external one without first removing the old one sitting behind the boiler, which means the boiler off?

 

[Bryan Williams]

Fancy having a notice 'Do not press this button'!

I was like Dougal in Father Ted looking at that..

 

[Neilj]

No need to remove the old one if it's not leaking, just pretend it's not there and forget about it.

 

[Bryan Williams]

No need to remove the old one if it's not leaking, just pretend it's not there and forget about it.

So I'm not quite clear here, can I fit an external tank without removing the old one?

Or is it boiler off, old one out, new external one fitted, boiler back on, which is is a gas safe job.
Cheers.

 

[Neilj]

Yes you can fit a new external vessel without removing the old internal one. As long as the old one isn't leaking you can just ignore it

 

[Bryan Williams]

Yes you can fit a new external vessel without removing the old internal one. As long as the old one isn't leaking you can just ignore it

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 !

It seems to be seated OK, not leaked again since I've been playing around with it tonight, just the pressure playing up still.

 

[Bryan Williams]

^^^^^ 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!

It's sat at 2 bar with the temp at 1 for the last hour.
I'll turn it off tonight but in the morning it'll be at zero, if I turn it on set at temp 3 I know will climb to around 2 bar in about 5 minutes, is it OK to start it at zero and let it come up to pressure?
Thing is if I give it a bit of a blip on the loop valve to get it to 1.5bar it eventually will rise to over 3bar,if I start at zero it just climbs to a safe spot.

 

[Seadog]

The boiler shouldn't fire up if the system pressure is low.

 

[Kayos]

The boiler shouldn't fire up if the system pressure is low.

It's a Worcester Bosch, they only stop firing at zero. Hence so many kebabbed heat exchangers

 

[Seadog]

Ah, how strange. Every other boiler I've ever cone across needs around half a bar minimum.

 

[gaz1]

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!

dont even touch that part under the boiler better known as the trv value causes more hassle than nothing when lazy plumbers wont fit a stop tap or gate valve on a system so you can drain it quickly

Ah, how strange. Every other boiler I've ever cone across needs around half a bar minimum.

not to my knowledge most boilers are set at 1 bar or just over the only ones that didnt was gravity fed system from water tanks in your loft

to the op makes a change seeing a drain valve tee off on a pipe most plumbers dont even fit them on most systems
i still prefer a tap tee on to them but thats me

 

[Beeezer]

over filled the old gel……

 

[Kayos]

Ah, how strange. Every other boiler I've ever cone across needs around half a bar minimum.

Fantastic when you are fitting on an old system, less good when said old system starts leaking

As above, have fitted hundreds from the Mk1 upto the 5, in theory they stop firing at 0.7, in reality it is zero

 

[Bryan Williams]

Morning peeps,
Quick update as you were all probably struggling to sleep with worry..

I turned the boiler off last night after running it a couple of hours at temp 1 with the pressure at 2bar.

This morning it had dropped to 1bar.

Turned it on to temp 1 and its crept up to 1.5bar.

It's not spat any water out since the first time I took it over 3 bar so I'm guessing I've been lucky and the prv has re seated, (if it was the pvr that leaked).

I want to recharge the expansion vessel today,but am unsure of the method, can I use a bike pump?

Do I first turn the boiler off, then pump it up, looking at the pressure dial to get it halfway between 1-1.5bar then fire it back up and see if it keeps a steady pressure without dropping overnight?

The house has been empty for maybe up to a year and I have no idea what maintenance if any they have given the boiler.

If it holds pressure do I have 2 options- 1, leave it be, its ok.?

2, take the opportunity to future proof and fit an external expansion
Vessel as the original isn't leaking ?

Or, if it doesn't hold pressure does that mean a new vessel, which is a gas safe job, as I understand it, I couldn't fit it myself having to take the boiler off the wall and it's no use fitting an external vessel if the original is leaking?

Cheers.

 

[Seadog]

not to my knowledge most boilers are set at 1 bar

I don't disagree with that. I said that they won't fire up below half a bar

 

[Seadog]

Morning peeps,
Quick update as you were all probably struggling to sleep with worry..

I turned the boiler off last night after running it a couple of hours at temp 1 with the pressure at 2bar.

This morning it had dropped to 1bar.

Turned it on to temp 1 and its crept up to 1.5bar.

It's not spat any water out since the first time I took it over 3 bar so I'm guessing I've been lucky and the prv has re seated, (if it was the pvr that leaked).

I want to recharge the expansion vessel today,but am unsure of the method, can I use a bike pump?

Do I first turn the boiler off, then pump it up, looking at the pressure dial to get it halfway between 1-1.5bar then fire it back up and see if it keeps a steady pressure without dropping overnight?

The house has been empty for maybe up to a year and I have no idea what maintenance if any they have given the boiler.

If it holds pressure do I have 2 options- 1, leave it be, its ok.?

2, take the opportunity to future proof and fit an external expansion
Vessel as the original isn't leaking ?

Or, if it doesn't hold pressure does that mean a new vessel, which is a gas safe job, as I understand it, I couldn't fit it myself having to take the boiler off the wall and it's no use fitting an external vessel if the original is leaking?

Cheers.

You need to release all pressure within the system. Use the drain valve (not the PRV), then use a bicycle pump. Overp pessure since the volume is so small. Then correct using a pressure gauge. Then refill the system from the loop to 1 bar. If you remove the cap from the pressure vessel valve, and rusty water is present, then it means that the diaphragm has failed. Fit a new PV somewhere else in your pipework. Just a note, I did once work on a system where the flexi hose to the PV had become blocked. That needed to be cleaned out since we couldn't quickly source a replacement.

 

[Kayos]

Before you do anything, press the valve with your finger. If there is water you are wasting your time trying to pump it up

 

[Bryan Williams]

Yep, water squirted out..

 

[Kayos]

Yep, water squirted out..

New vessel time