boiler loosing pressure fast over night

[angellonewolf]

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

cant pump up as dont think ive got any thing for it

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


thanks for all the help guys i think on this any cheaks that i can do from under neath and out side see if water leaking i will do but as for changing parts im not up for as the boiler works as is i dont want to get in a point that it dont work after me having looksee and as needs a service might have the bloke do the both
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.

and sounding like i might not want to touch this all info will make sure they dont get riped off i have a few plumbers that i can call but better for warned rather than take what they say as the bible but have used them for a time and they do seam good and fair

 

[sg66]

Plumber is fine for pipework, you need gas safe for boiler.

It takes nothing to isolate boiler with the valves and looking at the prv and pressure gauge is free if you do it

 

[earthman]

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

How would you actually fit one of those in practice?? By disconnecting the original one and by making/routing extra pipework/hoses?

 

[sg66]

If original is not leaking which usually they don't, you just break into the return pipe,
Right hand looking at boiler, fit a push fit tee, get a flexi (just cause it's Easy) 3/4 to 1/2.

Connect it into the tee, re fill system check for leaks.

The valve for checking the pressure vessel is on the top of the tank, you need to let the pressure out of the heating system and leave it open to check pressure and re pressure it if it needs it, it's just standard tyre valve so it's easy to check and re pressurise you must have a drain open on heating or pipe off to re pressurise experience tank.

 

[angellonewolf]

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

Plumber is fine for pipework, you need gas safe for boiler.

It takes nothing to isolate boiler with the valves and looking at the prv and pressure gauge is free if you do it

After rereading the thread I've remembered something later last year that the boiler pressure was getting high I had to put water in to pressure it it would work for a while but now I remember that I was there for a few hours and the pressure gauge was near the red I said this to my mate who called a mate from school that said as long as it's not in the later part of the red it's ok to run it until it gets fixed

A few things have happened and the house has not been used as they had to go sort term to a elderly peoples home and now I've been asked to do a little clearing up
When I went in there the first day I had to fill the boiler to get it to work but the next day had to do the same I'm going to have to see if the pressure is high in the boiler when it running and see as I'm sure I can add a external pressure tank and would save them them quite a bit if that's the problem in assuming I'd have to drain all the rads to put in the expansion tank ?

 

[sg66]

Set pressure to 1.2 bar, put heating on full belt, if tanks gone within 20min gauge will be at 3bar and the prv pipe will be spitting water out

Don't expect it to loose alot of water, as there is no room for expansion it doesn't have to loose much to drop like a brick when it cools down.

 

[ukracer]

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

Is that rads only and no hot water?

 

[sg66]

Is that rads only and no hot water?

Hot water rarely causes over pressure, unless pump fault.

A lot of this is guess work without knowing exact boiler.

 

[Kayos]

Hot water rarely causes over pressure, unless pump fault.

A lot of this is guess work without knowing exact boiler.

It's a worcester bosch 28i junior, cant see the full label but I'm guessing mk 4 or 5

Hot water on a combi with a failed vessel often causes prv to discharge in my experience

 

[earthman]

Hot water rarely causes over pressure, unless pump fault.

Thinking of the needle bouncing around/going into the red area on mine whilst the bath tap were on, and being criticized by another member on here for even thinking that the pump maybe be involved period, can you explain why/what sort of fault with the pump would cause this then?

 

[mtt.tr]

It's a worcester bosch 28i junior, cant see the full label but I'm guessing mk 4 or 5

Hot water on a combi with a failed vessel often causes prv to discharge in my experience

Ah what do you know, its only your profession

 

[sg66]

It's a worcester bosch 28i junior, cant see the full label but I'm guessing mk 4 or 5

Hot water on a combi with a failed vessel often causes prv to discharge in my experience

Only if your running a bath for a hippo in my experience lol

 

[sg66]

Ah what do you know, its only your profession

Sorry, my bad I guess 35yrs doing this rules me out.

 

[Craig-SM]

Surely hippo wouldn’t need much water in a bath due to displacement

 

[Rig Pig]

Surely hippo wouldn’t need much water in a bath due to displacement

Eureka!

 

[sg66]

Big baths haha

 

[mtt.tr]

Sorry, my bad I guess 35yrs doing this rules me out.

Maybe we need a harry hill fight

 

[sg66]

Clue is in rarely, without being in front of it everything is best guess and experience.

If you have a plate exchanger and a primary heat exchanger, gas heats primary, to get hot water the heating water is shunted round the boiler through the plate exchanger which transfers heat to your hot water, if the pump or control of pump fails the heat has no where to go, the boiler heating circuit in the boiler will boil an over temp fault will usually occur with banging and or spit water out prv.

If that makes sense, I'm now well lubricated with Stella

 

[sg66]

Maybe we need a harry hill fight

I never got Harry hill.

 

[angellonewolf]

Is that rads only and no hot water?

hot water and rads both working if pressure is in the boiler

It's a worcester bosch 28i junior, cant see the full label but I'm guessing mk 4 or 5

Hot water on a combi with a failed vessel often causes prv to discharge in my experience

the pic that i put up is not the actual boiler just one very similer