Potterton Suprima 50 Lock Out problem

Ladybird20

WAs this problem not featured onwatchdog about 18mths ago,,only the same thing happened to me and i had to get a replacement..it was weeks later when watchdog featured it, which was too late for me i had already paid for the replacement....They even wrote a template letter for you to print out to Potterton.....I wander if the template letter is still on the Watchdog site??I am sure you got a free repalcement as it was afault on 1,000's of potterton circuit boards????

frogeyesimon

Have suffered from lock-out problems with my Suprima 70 for a while - changed PCB, fitted auto-bypass valve, done much fettling all to no avail. Eventually I have found that by turning the boiler thermostat down to the 9 o'clock position the problem has gone away.

Give it a try - it seems to have worked for me and it's free !!

moneysavingplumber

frogeyesimon wrote: »

Have suffered from lock-out problems with my Suprima 70 for a while - changed PCB, fitted auto-bypass valve, done much fettling all to no avail. Eventually I have found that by turning the boiler thermostat down to the 9 o'clock position the problem has gone away.

Give it a try - it seems to have worked for me and it's free !!

I'd be surprised if you've not got 22mm primaries taken from the tails instead of the recommended 28mm upsize for 60s and above.

The PCBs are a known problem on these but they are not always the cause. There used to be a similar overheat lockout problem on the early Baxi Solos, another low water content boiler. I'm no expert on electronics but I know that certain reset mechanisms (mechanical and electronic) are often weakened every time they are caused to trip (mechanical overheat safety stats I work with on commercial catering equipment, for example, will eventually fail in the broken circuit state if they are tripped often enough, as well as electronic gas igniton modules with a reset function). Whether persistent lock-outs on Suprimas where the installations have been poorly designed or the boiler has been oversized has played a part in the demise of the obviously poor quality boards is something we'll probably never know, but I do know that I only ever fitted Suprims at the correct size for the property and always designed or modified the system strictly in accordance with Potterton's instructions, and can honestly say I've never had to replace a PCB on one that I've fitted, only on ones that I'd been called out to where faults in the installation were evident.

Having said all that, an associate of mine stopped fitting them after a PCB caught fire on one!

Yes it was featured on Watchdog a few years ago.

dave2412

There is a design fault on the Suprima range. Potterton have since replaced the open backed PCB with an enclosed version, which cures the fault. Not sure if they re-imburse customers who have had to replace theirs. But mine has just gone after 7 years so surely we have a case?

Wikster

Hi there, wish I'd found this site earlier

We have a Suprima 50L in the property we moved into a little over one year ago. In this time, we've had to "reset" the boiler on an increasingly regular basis -- what was once a month became once a week, once a day and is now multiple times per day.

In fact, it's got so bad that we've had two days in the past week where we had no heat at all.

The problem manifests itself as the red light flashing on the boiler and repeated presses of the reset button (the plastic membrane for which is now worn through...) to get it to reset/light.

Sometimes, the only solution is to switch off the power completely, leave it 5 minutes and then switch the power back on and relight. Even then, when the thing relights, it may only stay lit for 10 minutes or so

However, conversely, there are days when the damned thing seems to go garrety and will remain on all day rendering the house uncomfortably hot and we're opening windows, doors, etc. :mad:

The boiler was installed by a previous owner approximately 5 years ago. At which time, we believe he replaced a proportion of the plumbing including new rads and piping.

He did not, however, replace the room thermostat which is an old Honeywell unit in a poor state of repair. What would be involved in replacing the thermostat? Would I simply buy a new one (like this one at Plumbworld) and swap old for new?

Is there any mileage in me contacting Potterton direct? Or would it be practicable for myself, as a competent individual (albeit one more used to maintaining computer equipment than central heating!) to get one of the reconditioned PCBs mentioned elsewhere?

I'm thinking that if options 1 & 2 don't fix the problem then it's time to call a professional in

What say the resident gurus?

Cheers, R.

natwer

I had a similar problem 4 years ago and i fitted a brand new kit 5111603 that includee the harness. it all worked fine. but now i have had the same problem again but i am a bit logical ( i think ). The problem is that the boiler tries to ingnite ( one can see the sparking ) but fails to ignite. i thought of two possibilites. 1. The inlet value for the gas is not opening or 2. the voltage or signall from the pcb is not getting to the value to open.
i would not know how to replace the valve seems complicated but i tested the voltage to the power input to the value and i found that when the boiler does ignite the power reading was 212 dcv but when it failed to ignite it was 205 dcv . i am not sure if this significan or not but this was a constant observation . Same discrepency everytime. is it worth changing the valve ? or will changing the pcb do the trick. i found compumerv on ebay. will sell refurb pcb for £55 plus post with 1 years guarentee when one sends the old one it. any comments are welcome.

johnsmith0774

can anyone advise me on a problem i have with my potterton 50l?

when i press either hot water or heating the boiler fires up and runs for about 60 seconds then stops. it doesnt lockout with the red light but jsut stops. then after about 2 or 3 minutes it starts again for 60 seconds then stops.

i recently bought a 5111603 kit (albeit refurbished) and fitted it this morning hoping the problem would be solved but the same thing happened.

its really annoying me, does anyone know the answer?

EliteHeat

Why on earth would your first action be to replace the PCB when no symptoms associated with a failing PCB are observed?

The actual likely causes of failure are, in the order of likeliness:-

1 - Failing circulator pump - that fact that it hums or vibrates does not mean it's working.

2 - Failed thermister

3 - Failing boiler thermostat

4 - Faulty flow switch

johnsmith0774

Yes i know i think i was reading about the wrong kind of fault on a different forum and convinced myself it was the PCB.

i measured 240v across the pump and the pipes both side of it get hot so do you think this means that it is ok?

i removed both the thermistor from the pipe (but still had it connected) and it was hanging in the air. the boiler ran for about 2 minutes before locking out and the light was flashing red.

i removed the boiler overheat, still connected but with the thermistor fitted and it done the same fault as always - ran for 60 seconds then stopped.

can i ask what a flow switch is?

thanks for your help

johnsmith0774

by circulatory pump do you mean the one in the boiler or the big red one fitted it the pipe work that moves the water around?