Potterton Powermax HE 'A15' Lockout

m33ksy · 23 May 2013

Hi all, firstly apologies for such a long post! However any help would be greatly appreciated.

I have a potterton powermax HE boiler. It has recently had a new diverter valve and a new pcb and been serviced and all was well for a few weeks until now, Last week I noticed the pressure was low at around 0.9 so I turned the valve and topped it up as I have in the past however when topping up there seemed to be very little pressure going in and it took a long time to reach 1.5 then when the hot water was on the pressure would keep rising up and reach over 3 and then drop down again the next day. Now however I am getting error code A15 and after pressing reset the pressure is reading 0 and when I open the valve to top up the pressure nothing happens even though the analogue gauge near the valve reads just above 2. If however I deselect hot water the pressure seems to eventually go back to 1.5 until selected again and the A15 comes back on. I do however have hot water coming out of the taps but it doesn't seem to be as much as previously. After looking online I have read things about recharging the expansion vessel but unsure if that might help or not in this
case as the pressure somehow comes back?

Many thanks in advance.

adp240 · 23 May 2013

The expansion vessel may have lost all its pressure and may need to be recharged.
More likely though is that the diaphragm in the expansion vessel may have a puncture. This would be why it took so long for you to top up the system when the pressure was lost. If this is the case, the expansion vessel will need to be replaced.

m33ksy said:
Hi all, firstly apologies for such a long post! However any help would be greatly appreciated.

I have a potterton powermax HE boiler. It has recently had a new diverter valve and a new pcb and been serviced and all was well for a few weeks until now, Last week I noticed the pressure was low at around 0.9 so I turned the valve and topped it up as I have in the past however when topping up there seemed to be very little pressure going in and it took a long time to reach 1.5 then when the hot water was on the pressure would keep rising up and reach over 3 and then drop down again the next day. Now however I am getting error code A15 and after pressing reset the pressure is reading 0 and when I open the valve to top up the pressure nothing happens even though the analogue gauge near the valve reads just above 2. If however I deselect hot water the pressure seems to eventually go back to 1.5 until selected again and the A15 comes back on. I do however have hot water coming out of the taps but it doesn't seem to be as much as previously. After looking online I have read things about recharging the expansion vessel but unsure if that might help or not in this
case as the pressure somehow comes back?

Many thanks in advance.

Gas2Air · 23 May 2013

There's a water pressure sensor on these that get partially blocked and give duff readings on the board so acting the A15 fault. The fill loop is probably choked aswell.

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Potterton Powermax HE 'A15' Lockout

m33ksy

adp240

Gas2Air

DIYnot Local

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