Potterton suprima 60 - won't go off!

[Andrew1981]

Hi all,

It's that time of the year that you find out the heatings not working as it should!

I have an old Potterton Suprima 60 that provides hot water and heating. The hot waters been on 20 mins a day (via a honeywell timer that also controls heating) over summer, but the heating has been off for 6 months.

I've turned it on earlier and it fired up well, house was toasty. Went to turn it off (via the honeywell timer) and it didn't turn off. Spun the thermostat to the minimum, and moved both 'hot water' and 'heating' to 'off' on the panel..... And the boiler is still firing! The only way to stop it is to turn the boiler to 'off' on the boiler itself.

Before today I'd leave the boiler on, heating to 'off', and hot water to 'on twice a day', and the boiler would fire up for 2x10 minutes a day. Now the heating and hot water are permanently on

I've tried to reset it, and despite holding the reset button for various periods of time, it doesn't seem to do anything, the lights stay doing what they are doing.
I've turned it off and on and it fires up and stays on.

I'm no expert at all on this, but initial research suggested the motorised valve (for it not turning off). The potterton fault finder suggested the thermistor
, but the fact I can't reset it suggests (to me) it could be the circuit board.

I'd be very grateful for any suggestions as to what it could be, or other ways to diagnose the fault.

Thanks in advance,

Andrew

 

[terryplumb]

The motorised valve would be the first thing to rule out.

 

[Andrew1981]

Hi,

That's what I thought.

I had 2 x ports. Using the metal toggle on them, both were loose when there was demand, but only one had the spring tension on when no power. I was in the process of removing the head and it started to work, that movement must have loosened it enough and now the system works fine.

Thanks for your help, thought I'd post the reuskt in case others have the same issue.

Now to figure out why the red expansion vessel is leaking water when I press the bike valve at the bottom (failed membrane it seems!)

 

[terryplumb]

Thanks for letting us know.

 

[ianmcd]

Now to figure out why the red expansion vessel is leaking water when I press the bike valve at the bottom (failed membrane it seems!)

No it needs recharged properly, plenty of posts on here telling you how to do it PROPERLY, there are no short cuts

 

[Andrew1981]

Hi, my red expansion vessel is next to the boiler, with the pipework entering the vessel at the top, and a bike valve a bike valve at the bottom.

When I pressed in the bike valve, water dribbled out which seems to be a failed membrane from my research. (my plan was perhaps to replace the vessel)

Are you saying it may be something else, and should just be recharged 'properly' (which seems to vary depending on which thread I read!)

Thanks!

 

[ianmcd]

You MUST leave a drain point open somewhere on the system, doesnt matter where , then pump the vessel up to the stated pressure , then close the drain point then re-pressurise the system, if you dont leave a drain point open while doing it, then absolutely no point in even trying