Potterton Suprima 50 Lockout

[DaveR]

I know this problem is well documented as I have read all the related posts. I have taken a lot of the advice on board but not found the solution.

I have suffered with the dreaded lockout for about a year. I have had replaced the PCB (brand new one), Air Pressure Switch and, I think, the gas valve?

After a lockout I often have trouble resetting even if I switch it off/on at the spur. I have watched the boiler trying to ignite but not being able to do it after 3 attempts. Once I get it going it sometimes works for up to 12 hrs but without fail I reset every day, which is so frustrating.

Thinking it might be connected to the overheat stat I turned the boiler stat down to about 10% but this had no effect. I thought I was onto something as my hot water is still scalding hot and the stat on the hot water tank is set to about 60 degrees.

I haven't had the overheat stat replaced yet-but if the water is so hot is the overheat stat not doing its job? Maybe the answer is obvious to you experts out there!


Thanks in anticipation for any help.

Dave

 

[DP]

Motorised valve should shut down the HW zone when cylinder temperature reaches that set on cylinderstat. If this is not happening, investigate motorised valve action.

 

[ChrisR]

Effin Suprimas. As DP says it looks like there's an external fault, though 60 degrees is hot - full thickness burn on a child in 2 seconds iirc. Try it at 50. Though if you have a single 3 port valve it will be open to HW when "at rest". So if the boiler is getting extra hot for some reason extra energy could be getting through on gravity circulation. It's only a "50" though, they do go up to 120..

May be worth unplugging all the connectors from the pcb and cleaning the pins on the board - a typewriter (remember them?) rubber is good for that.

Test the boiler themostat - when the boiler is hot with the stat set high, it should click and turn off when the knob is turned down.
When the pig is trying to light there should be volts on the gas valve and gas coming ot of it. You could check for the volts but beyond that is corgi territory.

 

[DaveR]

Thanks for the help so far guys.

I've turned the cylinder stat down to 50, but the HW is still scalding hot. The motorised valve is a Honeywell 4073A model with 'auto' on left and open/man on right. The lever seems to be permanently in the auto position. I don't think I've ever seen it on the open/man position. Is this the behaviour one might expect or should it move when CH and/or HW kicks in? Is this isn't functioning properly could this be causing the lockouts?

The heating hadn't kicked in this morning as I'd expected but had not locked out. The pipes from the motorised valve were quite warm but the radiators were freezing, so I turned the boiler stat up to max from its previous 10% position and the boiler fired up. When the boiler got warm I turned the boiler stat down as suggested and the boiler switched off. So it seems the boiler stat is working OK.

As for the PCB, it is a brand new one that has only been fitted for about a week. I've noticed when I do get a lockout the pump continues to run until I reset the boiler. Is this something you might expect?

When I've had to reset the boiler I've watched it fail to ignite after 3 attempts and sometimes it takes a while to get going. Does that tell you that the lockouts are probably not related to the overheat stat?

Thanks again.
Dave

 

[maxuk]

I have a potterton boiler and the problems you describe and change about every thing and yet the same old thing goes on for a bit then the amber light comes on or the red light rest and still the same keep's cutting the next stage for me is to replace the boiler potterton have a lot to answer for they are crap !!!!

 

[nickso]

I have a potterton boiler and the problems you describe and change about every thing and yet the same old thing goes on for a bit then the amber light comes on or the red light rest and still the same keep's cutting the next stage for me is to replace the boiler potterton have a lot to answer for they are crap !!!!

an informed post and no mistake. i think i shall use this as a benchmark for all future potterton faults as a possible solution, what other solution can there possibly be apart from "potterton have a lot to answer for they are crap !!!!"

this is obviously only applicable to 7 year old posts.

 

[DanEast]

Hi - I have a Potterton 50 HE - Its been in since 2005 so i cannot complain in regards to reliability - although its starting to intermittently lock out - generally it was coming on in the morning with no issues, and only locking out in the afternoon when it came on....once locked out i would reset and it would fire second attemp every time.......although today it never fired in the morning.....reset and it fired. The fault light is indicating ignition error....any ideas? im thinking of replacing the spark ignitor and or the spark lead.....do you think it could be the PCB as well? any help would be appreciated - thanks