# Worcester boiler problem



## wanner69 (Mar 14, 2010)

Is there anybody that can advise me on my boiler problem. Basically its losing pressure after the central heating has been on for a few hours on timer, the next morning when I check the gauge its at zero. Im having to top it up with water to get 1 bar of pressure back in. Everything is fine again until I check again the next morning and zero pressure again. When running, the boiler pressures up to around 2.5bar. Now I have no leaks anywhere. I've checked for water coming from the expansion tank via the valve and only air comes out which is correct. The pressure release valve was changed last year and all is fine with that. Can anyone offer any advise or solutions. Thanks


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## dholdi (Oct 1, 2008)

Is it a condensing model ?


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## kev999 (Feb 16, 2007)

Check the exhaust pipe from pressure relief valve to see if disappearing from there, relief valve might be lifting when it's up to temp.


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## Deadshot (May 23, 2017)

If you have let air out of the expansion vessel have you topped it back up ?


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## wanner69 (Mar 14, 2010)

Deadshot said:


> If you have let air out of the expansion vessel have you topped it back up ?
> 
> Sent from my iPhone using Tapatalk


Yes back to 0.8 bar


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## wanner69 (Mar 14, 2010)

kev999 said:


> Check the exhaust pipe from pressure relief valve to see if disappearing from there, relief valve might be lifting when it's up to temp.


The prv will only lift when and if it over pressurises doesnt it? Is this the pipe from the prv that goes through the wall to the outside of the house? That does drip occasionally.


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## wanner69 (Mar 14, 2010)

dholdi said:


> Is it a condensing model ?


Combi boiler buddy


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## dholdi (Oct 1, 2008)

My first thought was the relief valve, but your first post implied that you have checked that. The pressure in the expansion vessel should be checked when the system is empty.
If there is not enough pressure in the expansion side of the expansion vessel then it will over pressurise and possibly lift the prv. If there is dirt under the prv seat this can prevent it from shutting completely. With the system off do you get any water coming out of the condense drain ( why I asked if its condensing )


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## wanner69 (Mar 14, 2010)

dholdi said:


> My first thought was the relief valve, but your first post implied that you have checked that. The pressure in the expansion vessel should be checked when the system is empty.
> If there is not enough pressure in the expansion side of the expansion vessel then it will over pressurise and possibly lift the prv. If there is dirt under the prv seat this can prevent it from shutting completely. With the system off do you get any water coming out of the condense drain ( why I asked if its condensing )


Thanks for the reply. I'm going to check the expansion tank tomorrow morning again. I occasionally get a drip from the pipe that goes through the wall to the outside. It's like a drain or overflow pipe, think it's from the prv possibly?


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## dholdi (Oct 1, 2008)

There could be 2 pipes to outside, the prv and the condense, although it is acceptable to run the condense to an internal drain. I prefer internal as there is no risk of it freezing but sometimes its not practical. 
The prv should be in copper and the condense in 21.5mm plastic internally changing to 40mm plastic just before it goes outside if it does. Some installers route the prv to the condense drain which is a bit naughty.


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## wanner69 (Mar 14, 2010)

dholdi said:


> There could be 2 pipes to outside, the prv and the condense, although it is acceptable to run the condense to an internal drain. I prefer internal as there is no risk of it freezing but sometimes its not practical.
> The prv should be in copper and the condense in 21.5mm plastic internally changing to 40mm plastic just before it goes outside if it does. Some installers route the prv to the condense drain which is a bit naughty.


Mine is copper that goes through the wall to the outside buddy.


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## bigalc (Aug 7, 2014)

I have a 28i and had exactly the same problem which was fixed when the plumber changed the expansion vessel
The outside pipe was dripping when the pressure went high.


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## ScaryLady (Jul 8, 2006)

If you’ve ruled all that out, you have a leak somewhere on the system. We had tiny leak on a pipe where a floor board had been rubbing it


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## kev999 (Feb 16, 2007)

wanner69 said:


> The prv will only lift when and if it over pressurises doesnt it? Is this the pipe from the prv that goes through the wall to the outside of the house? That does drip occasionally.


Yep thats the one , it shouldnt drip,mit means the valves passing.


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## wanner69 (Mar 14, 2010)

Thanks for all the replies guys much appreciated. After further investigation I do in fact have water coming out of the valve in the expansion vessel so I will order a new one and get someone to fit it. Looks a pig of a job for access.


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## staffordian (May 2, 2012)

wanner69 said:


> Thanks for all the replies guys much appreciated. After further investigation I do in fact have water coming out of the valve in the expansion vessel so I will order a new one and get someone to fit it. Looks a pig of a job for access.


Before you do that, ask about fitting a generic EV elsewhere in the system.

We had an Ideal Isar boiler which had a faulty EV and not only is it ridiculously expensive, half the boiler has to be dismantled to get to it.

Our plumber got a standard EV from somewhere like Screwfix and installed in in the loft, leaving the existing one in place.

I think it has to ideally be installed on the return pipework IIRC but doing it this way was far easier and far cheaper.


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## wanner69 (Mar 14, 2010)

staffordian said:


> Before you do that, ask about fitting a generic EV elsewhere in the system.
> 
> We had an Ideal Isar boiler which had a faulty EV and not only is it ridiculously expensive, half the boiler has to be dismantled to get to it.
> 
> ...


Thanks for the reply mate. I have read about fitting a second EV so I will discuss that with the plumber tomorrow cheers


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## dholdi (Oct 1, 2008)

Ian's solution is a good one if you can find the room for the vessel.


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