Potterton Boiler Valve Configuration.

[Doug99]

Hi All
My daughter has just move into a property with a Potterton Combi boiler.
Central Heating and Domestic Hot Water are working fine, but the CH pressure gauge raised to over 3 bar and the pressure vent was opening.
With CH switched off I bled a radiator to reduce the pressure, but it would not reduce to below 2 bar, I assumed the closed system was being continually fed from the mains.
On checking the boiler isolation valves, all the coloured valves were 'open'.
Eyeballing the layout I assumed the inner blue valve is the one which is used to 'top up' the CH system.
I closed the valve and managed to reduce pressure to 1 bar (cold), Run the CH for a while and the pressure only raised a little further.
Grateful if you would check the attached pics and confirm the valve configuration is now correct?
Cheers All.

 

[oldbuffer]

Looks to me as if both blue valves should be closed. i.e. handles at right angles to the body. At present, only the inner of the two appears to be in the off position.

 

[Doug99]

Looks to me as if both blue valves should be closed. i.e. handles at right angles to the body. At present, only the inner of the two appears to be in the off position.

Thanks oldbuffer - does that mean both blue valves are opened to 'top up' then both closed on completion?
Originally all valves were left open.

 

[oldbuffer]

Correct. Both open to top up, both closed when finished.
To top up - blue handled valves:
1. Open outer valve.
2. Open inner valve, slowly.
3. Watch pressure rise to expected level - around 1.2 to 1.5 bar.
4. Close inner valve.
5. Close outer valve.

 

[Doug99]

Thanks again oldbuffer - but why are there 2 valves for the top up process?
I would have thought the use of the inner blue valve would be sufficient to control the mains feed.

 

[ianmcd]

Thanks again oldbuffer - but why are there 2 valves for the top up process?
I would have thought the use of the inner blue valve would be sufficient to control the mains feed.

it is to conform to water regs

 

[denso13]

but why are there 2 valves for the top up process?

Because in theory you should close both and remove the bend in between the valves when not in use so the pipework is not permanently connected. The two hanging caps would be used to cap the valves when the bend is removed.

 

[bernardgreen]

Two valves to enable the filling loop to be removed when not re-pressuring the system. Removal ensures that water from the heating system cannot get into the drinking water supply

 

[Doug99]

On another matter - How can I establish what spec of Potterton Boiler is fitted? Its a 4 bed detached house, mum/dad and 4 toddlers so am keen to establish whether the boiler is up to the job.
Cheers All

 

[Ronaldo1]

Looks to me as if both blue valves should be closed. i.e. handles at right angles to the body. At present, only the inner of the two appears to be in the off position.

@oldbuffer i'm slightly confused what is inner and outer valves. The inner valve (on the right) looks to be in the on position. And outer (on the left) looks to be off.

 

[oldbuffer]

1. There are two valves with blue handles.
2. The one closest to the yellow handled (gas) valve is the one I refer to as the inner.
3. These valves are normally:
3.1 Off (closed) when the handle is at right angles to the long body of the valve.
3.2 On (open) when the handle is parallel with the long body of the valve.
4. On the above basis it seems to me the the inner valve is off, and the outer is on.

 

[Ronaldo1]

1. There are two valves with blue handles.
2. The one closest to the yellow handled (gas) valve is the one I refer to as the inner.
3. These valves are normally:
3.1 Off (closed) when the handle is at right angles to the long body of the valve.
3.2 On (open) when the handle is parallel with the long body of the valve.
4. On the above basis it seems to me the the inner valve is off, and the outer is on.

@oldbuffer thats great thanks for clearing up