Combi Boiler Off pressure going up!!

[RichB]

Hi

I have just had a combi boiler resited in my flat (Worcester 24CDi).
Everything seemed to be fine for a couple of weeks and the pressure was at 1bar.

I repainted an old radiator with radiator paint and the instructions told me to turn the radiators up to max temp on the boiler (which I did for a while).

I'm not sure if it was as a result of that, but now the pressure is constantly increasing even when the boiler is turned off!!
(The filling key is not in the boiler)

I think I understand why if there is a leaky diaphragm in the pv why the pressure will rise a great deal if there is not enough air to balance the pressure.

But if it is a closed system and the boiler isn't even on how can the pressure be increasing?

Any explanations/ideas will be really appreciated,

thanks for any help,

Rich

 

[oilman]

Is your pressure vessel ok?

 

[boxster]

that is very common on those boilers. if its only been in a sort period of time give the makers a call they will come out and replace the valve. something gets stuck and jamms which causes the cold water to fill all the time. All we can do when we attend new boiler calls is turn the cold off untill Worcester can call. If its been in for longer you need a plumber to replace the valve. it only happens on the 24cdi range?

 

[COG]

If your filling key is out and the pressure rises constantly (only falling when it discharges out of the prv )and you dont have to re top up the pressure then its your water to water heat exchanger that is faulty and needs replaceing £210.00 from Worcester inc vat.

 

[ChrisR]

Yes. Prove it by turning off the cold water inlet valve overnight. Then get a soft prat like me to replace the heat exchanger , admitting that they cost less than £30 if you know where to go.