boiler loosing pressure fast over night

[angellonewolf]

what can it be and possablie to repair myself or leave to the big boys ?
i do not know the type of boiler but its a worcester

looks quite like this with out as meny buttens and the middle dial is all gray so possably an earlyer model than this aprox 15 years old could be a bit more the switch for the on off timer is the same but think is gray as well

ive looked over the rads all seam dry and this has been on going for quite a few months but now got to a head as person is not there as had to move in with the daughter and i been over there and the house is smelling a bit musty (not lot as if i pressure the boiler and put the heat on its works fine but now over night looses the pressure

 

[outofthefire]

You could have a weeping joint or leak under the floor boards. Are the radiators upstairs hot or are you needing to bleed them a lot.

 

[WorkshopChris]

Can you see any signs of discharge from the boiler safety discharge pipe?

 

[Craig-SM]

Looks like you have a Worcester Bosch Greenstar Junior. If you have water coming out of the overflow pipe it would be your pressure relief valve that needs replacing. Possible to do yourself but ensure you get new seals for any parts you remove.
If no water from the overflow pipe then it could be the diaphragm in the expansion tank which most likely will be a sod to get at so best left to a professional

https://www.worcester-bosch.co.uk/support/literature/download/release/8716115166/12640

 

[The_Yellow_Ardvark]

@angellonewolf

May not be related.

But the last week I am dealing with call outs to sites with automatic sprinklers. Linked to Fire alarms.

8 times in the last week I have to attend sites, as over night the mains in pressure has dropped. But returned.
Check with your water board to see if they doing works, or ask your neighbours if they are loosing water pressure.

As I said, may not be related.

 

[angellonewolf]

You could have a weeping joint or leak under the floor boards. Are the radiators upstairs hot or are you needing to bleed them a lot.

there is only 3 rads in the house (dont even start me on that) all down stairs and in concreat so i hope not but no damp patches what i would hope to see if that the problem and no blead only 2 times a year normaly

 

[angellonewolf]

Can you see any signs of discharge from the boiler safety discharge pipe?

now that a thought im assuming that out side will have to have a look at that

 

[Kayos]

Heat exchanger split and going down condensate pipe is fairly common.
Failed expansion vessel and or blow off valve is also common

 

[colnerov]

Copper pipes in concrete is not a good idea, they can corrode in certain conditions.

 

[angellonewolf]

Looks like you have a Worcester Bosch Greenstar Junior. If you have water coming out of the overflow pipe it would be your pressure relief valve that needs replacing. Possible to do yourself but ensure you get new seals for any parts you remove.
If no water from the overflow pipe then it could be the diaphragm in the expansion tank which most likely will be a sod to get at so best left to a professional

https://www.worcester-bosch.co.uk/support/literature/download/release/8716115166/12640

what would be the price for each fix appox ?

 

[Kayos]

what would be the price for each fix appox ?

Changing the vessel is boiler off the wall or at least remove the flue, not diy

 

[RonA]

If the pressure goes sky high (assuming press about 1 barg before starting) when you run the boiler, the internal pressure expansion vessel diaphragm has gone. It can rise far enough to lift the safety vessel causing pressure to fall drastically once boiler cools.
You can get external expansion vessels, fit one & then just abandon the internal one. Saves having to get the boiler opened up to replace the internal one.
RonA

 

[angellonewolf]

Changing the vessel is boiler off the wall or at least remove the flue, not diy

when i say a price i mean boiler/gas safe person

 

[Kayos]

when i say a price i mean boiler/gas safe person

2 most hated jobs on a Worcester boiler

If it's easy access I'm parts plus £150 plus vat, if boiler has to come off you can double that as it needs a full recommission. If vessel is ok and will pump up you will get it a lot cheaper than that

 

[angellonewolf]

2 most hated jobs on a Worcester boiler

If it's easy access I'm parts plus £150 plus vat, if boiler has to come off you can double that as it needs a full recommission. If vessel is ok and will pump up you will get it a lot cheaper than that

its got to be done how much for part ?ish

access is fairly easy as nothing round it for 3/4 of a foot

 

[Kayos]

https://www.dhsspares.co.uk/product/worcester-87161064310-prv-1014899

https://www.dhsspares.co.uk/product/worcester-87161055450-expansion-vessel-1014641

May not need the vessel though, it might pump up

 

[waddycall]

Might just need a new Schrader valve in the vessel. Check it for leaks if you pump it up.

 

[Craig-SM]

what would be the price for each fix appox ?

I think Kayos has answered that better than I could

 

[sg66]

Have you verified the water is being pushed out of the prv?

Fooked heat engines are very common.

Top up boiler, isolate it from the heating circuit via the 2 iso valves on the flow and return under the boiler, leave overnight, if pressure stays put its likely on the rads/pipes.

If it's still loosing water check the condensate to see if water is running down it, that will confirm if the heat engine is porus

As kayos has stated pressure vessel my re pressurise.

You can rule out pressure vessel by draining one of the rads to create an air pocket as temp fix, prvs very often continue to dribble though as once they open on an old boiler they don't like to re seal crud etc.

External expansion tank can be fitted should cost you very little for a 10Ltr a flexi and a pushfit tee, as long as you have somewhere for it to live.

 

[sg66]

If it's Greenstar with experience tank on rear, flue needs to come off if flue goes straight out the wall to the rear if you follow.

An hour including drinking tea if boiler needs to come off 2hrs plus at least 3cups of tea and buscuits, it's the biscuits that push the price up

All assuming it's a Greenstar with wall mounting jig, jig and tank are separate from boiler.