Worcester Bosch 28CDi - what's a normal system pressure rise from cold to hot?

[Rory]

Boiler is in daughter's recently acquired house. System has 7 single panel radiators.

With the cold pressure on 1.2 bar, it rises pretty quickly to about 2.5 bar when hot.

I found my neighbour has exactly the same boiler and that barely moves - a couple of tenths of a bar.

Is the pressure rise anything to be concerned about, and is there a logical reason why they would they be so different?

 

[Killy Bing]

Boilers been poorly maintained 🙂 best bet is to get it serviced and say about the pressure rise. Should be a quick fix.

 

[Rory]

It's been serviced every year and recently had a new diverter and DHW heat exchanger fitted by a somewhat stroppy Scottish Power engineer. He just shrugged and said "they vary" when asked about the pressure (he seemed under a lot of pressure himself 🙂 ).

 

[Jimbob]

As said get somebody decent in to give it a decent service. A decent engineer will sort that problem in no time, it's quite common.

 

[simon0703]

He was stroppy because he had to change divertor, is a terrible job. I work for sse, same conpay. Give them a call to arrange a visit for a breakdown. Its a quick job

 

[Rory]

He'd been told to change the diaphram, but decided to change the whole unit as there were signs of it leaking. He spent half the time "talking" to his office who were trying to get him to fit another call in (he'd wanted to start ours at 8PM one evening but we said no).

The pressure vessel seems OK - it's at 9PSI with the water pressure at zero.

 

[AWheating]

Got a lot of large double rads? Your neighbours could have a dodgy/blocked pressure gauge.

 

[TBServices]

A "service" from any of the big energy firms isn't a service at all.

It needs a service.

 

[Rory]

A "service" from any of the big energy firms isn't a service at all.

I suppose there's a limit to what they can do in 20 mins. 🙂


What could happen during a service which would limit the pressure rise, or is it perfectly OK to be going up?

I was thinking that if the pressure vessel had failed, then the pressure would increase dramatically and eject water from the release.

 

[Richie_77]

Pressure within the vessel should be about 1 bar without any load from the water

 

[Rory]

Pressure within the vessel should be about 1 bar without any load from the water

Thanks for that,

Went back to it today. All the pressure has gone out of the system and the pressure vessel doesn't have any pressure either. Worse, water splutters out of the valve.

Hmm....can anyone guide on how I should describe that to Scottish Power obviously with a view to getting them to change the vessel? Their grumpy engineer isn't going to very happy about that!