Potterton suprima 60 boiler fault

[cjb2611]

Hi, would like some help please diagnosing a fault with my 12 year old Potterton Suprima Boiler. The problem is it will fire up when the timer comes on and will run for a short while however before the radiators have got warm the boiler shuts down. The control panel shows a steady red light and a slow flashing green light which I believe means the temperature required has been reached. The boiler then fires up again after about 20/30 minutes and only stays on for anything between 2 to 5 minutes, nowhere near long enough to warm the rads. It continues doing this all throughout its timer cycle but never locks out which is a major fault with these boilers. Any help would be greatly appreciated. Many thanks

 

[Puddle]

Seems like it is coming on heating up ok ,reaching temp and cutting off,so boiler operation seems ok,problem points to a circulation issue,possible pump on its way out or blockage/restriction in system maybe

imho

 

[cjb2611]

Hi puddle and thanks for the reply. When you say that it's heating up ok I guess you mean the water to circulate around the rads. Unfortunately that is not the case because when I feel the pipe from the 3 port valve it's only luke warm. By the way I recently replaced the head on the motorised valve because the motor was a bit clicky.

 

[Puddle]

You should check to temp of the pipes above boiler not at valve,are they hot,if so as said boiler operating but circulation problem,is your hot water ok/getting heated ok,what make of motorised valve do you have ?

 

[cjb2611]

Grundfos pump working fine motorised valve is Honywell V4073. Regarding temp above boiler it depends if water has been drawn off for shower/bath.

 

[jtsplumbing]

Suprima famous for PCB, has yours ever been changed ? if not new one is a real pain in the Backside to fit, you have to re-wire the complete boiler, But you may be lucky and its not the PCB >>

 

[Puddle]

Grundfos pump working fine motorised valve is Honywell V4073. Regarding temp above boiler it depends if water has been drawn off for shower/bath.

think you are checking cylinder not boiler

 

[Billy Bob Bob]

this could be a bit slow and tedious puddle the amount of times people refer to a cylinder as the boiler:wink:

 

[jonmanty]

It's gotta be a circulation problem, that's the reason why the boiler only fires for short periods.

Check the pump first, after that it will be some form of a restriction in the system.

Jon

 

[cjb2611]

Hi, sorry for that both are hot right hand one more so than the left side one.

 

[Mbear]

Defo pump

 

[cjb2611]

Checked pump and it appears to be working fine and it was only replaced 2 1/2 years ago.

 

[GrahamM]

Out of interest, how are you so sure your pump is sound? An old dirty system can easily do in a pump in a year and you do get the odd dodgy new pump as well.

 

[WHPES]

Potterton have poor quality circuit boards which are prone to failure.

 

[cjb2611]

I'm as sure as I can be without taking it off. This morning it has been running fine and the rads are hot. Boiler keeps coming on and shutting down so I don't think it's the pump. I checked it last night with a small screwdriver and it was spinning freely. Regarding the system being dirty I flushed it out 2 years ago with sentinel X400 and then refilled it with sentinel X100. Do you think it needs doing again.

 

[barronbathrooms]

Faultly pcb board is the most common fault with these boilers. They tend to make the boiler act erratic and intermittent. the council fitted thousands in my area changed a fair few over past few years. Something to do with the the poor soldering on the boards. google it to find out more info.

 

[rsr]

I'd say this is either a circulation issue or a knackered high limit stat. Prime suspects before a pcb change.

So either the heat generated at the boiler is not getting round the system (blockage, sludge, poor design etc) and tripping the high temp thermistor at the boiler or the thermistor is broken (check resistance - Potterton technical will give you required ohms details) .
Put in a Magnaclean if you don't already have one.

 

[Puddle]

It is possible the time delay on pcb is faulty,thus not send to lock out but would expect water in boiler would go cool when heating on and boiler not working,however pipes above boiler remain hot,in any case the boiler is indicating it has reached temp and when cools down ,boiler comes back on

The hot water is working ok

We also have a 3 port valve in system,thats normal un-powered position is hot water only mode that could be sticking or syncron motor on its way out

 

[warrington]

flashing red light is pcb fault, that boilers are famous about this fault. i have changed one 2 days ago. Better to get replacement kit which is 206pounds inc vat.

 

[jtsplumbing]

Pain in the backside , you have to re-wire all of boiler.

 

[SPH]

Hi, to me it sounds like a circulation problem, i would check the system for air, bleed the rads and check that the header tank in the loft has water in it about 1/4 full (the small tank) there is a common fault with these boilers PCB if you have a round rest button and a round grey temp control knob on the boiler then you have the old style PCB, they are fairly easy to fit but do cost abit to buy approx £200.00 +

 

[weeman]

sounds like faulty thermistor

 

[5544]

have you considered checking the flow and return temperatures for the boiler. if the differential is correct then it is not a flow problem. then you can assume PCB problem or the dry pocket thermistor which is rubbish and fails.

 

[cjb2611]

Hi All,

It was the PCB had dry joints all over it. Had it replaced and now everthing is fine.

Many thanks for all the replies.

 

[iamanshul]

Hi, I have a Potterton Suprima boiler at my flat with underfloor heating. Few months back, my circulating pump burnt out. The plumber replaced the pump and the flow switch. But after that intermittently my boiler light turns red. every few days. if i press reset it works. Now I would say it is happening more frequently, once every few days. Can you guys please help what could be the problem ? From what I hear it could be PCB. I will change it but want to be sure if thats the only problem.
Anyway I can diagnose the problem myself before calling someone?

Thanks