Potterton Suprima gas boiler - worth repairing?
I’ve had a number of enquiries recently from people with Potterton Suprima boiler breakdowns, asking me if I think they are worth fixing given most are approaching 20 years old. My quick answer is always “Yes”.
A more detailed answer would be yes they are a basic and simple boiler nearly always a quick and easy to fix, but sometimes expensive.
By far the most common breakdown is control board failure which can manifest itself in a variety of ways. A brand new control board has risen to almost £300 now (August 2022) plus the cost of the visit to install it, but the good news is I can fit a reconditioned exchange control board for far less. Typically around £100 for the part although still plus the cost of the visit. The cost of a visit varies widely, depending mainly on how far away you are from me (near Hungerford Berkshire) and consequently how much driving time is involved in a trip to you.
Most Suprimas have a control board inside a grey plastic box and changing it is ‘plug and play’ (or ‘plug and pray’ some people say, lol). Early versions occasionally still have the original control board with all the electronic components exposed and visible. This early PCB can still be replaced with a exchange reconditioned board of the ‘grey box’ type but it means a rewire of the boiler and installation of a new wiring loom. Most Suprimas have already been converted to the later grey box type of board though.
Other problems which can be mis-diagnosed as control board fault are air pressure switch failure, gas valve failure, pump failure and the boiler genuinely overheating. These are unusual though. The most common non-control board failure is the flue fan. Again easily replaced.
I’ve written more about Potterton Suprima Boilers in more detail on my separate website for Suprima boilers:
suprima-repairs.co.uk
HI – thanks for your great sites. WE have a potterton suprima 80 and need some advice on isolating an issue.
From our main fuse box to the thermatic controller just outside the boiler is all fine – nothing wrong with electric. you can turn on the main on off button to on and the controller lights up and stays amber.
the minute I go to turn on heating or hot water, I can hear the pump slowly start up , it doesn’t even start the first process of igniting the pilot fo the boiler – it just clicks off the main circuit to the house.
The pilot light isn’t on when this process starts and it doesn’t come on at the beginning of the cycle either.
Any help would be much appreciated.
Kind Regards
Leanne and Shaun
Hi Leanne,
Yes I’ve encountered this exact fault before. It is usually a failed flue fan in the boiler – it probably needs replacing.
One other possibility is failure of the pump but this is less likely given you can hear it start running.
Hope that helps,
Mike
Hi Mike I have a potterton suprima 30 it’s now 25 years old and running perfectly . It’s had two fans and a pcb in all those years and my question is is it time to replace it with something modern re advice from my gas engineer thanks in advance
Hi Karl. Apologies for missing your question. There are so MANY Suprimas still out there giving good service I think parts will still be available for some years still. Modern boilers do tend to fail more frequently than older so its a trade-off. You’ll get slightly better fuel efficiency in return for higher maintenance costs. Your call!
Hi Mike, Completely agree. Our SuPrima lasted 18 years before we decided to upgrade. Our original PCB ‘fried’ but we were able to buy the improved version and it has run just fine ever since. As you say, it’s a simple device and does the job.
Indeed. They are really easy to fix compared to new boilers with all their opaque fault codes which often don’t help much when you look them up. So few things to go wrong on the suprima!
Your writing is very useful. Many of my questions have been answered, but I still have many more. What a relief! Excellent article; we’ve been wondering if it’s worth fixing our old potterton suprima gas boiler and this answers our questions. A fantastic article, indeed!
Thank you for your kind comments. My apologies for not noticing your post until now. Feel free to ask more questions if the moment has not passed!
Kind regards, Mike
Hi Mike the boiler man…! I have a Potterton Suprima 100L and was troubleshooting a problem online when I came across your blog.
The problem I have is that the boiler has stopped firing up when it receives a signal from the timer. The hot water still works fine off the timer, but the heating doesn’t. I’ve checked out all the timer outputs and getting signals as required. I can switch on manually by taking off timer and switching to ON position…. It just seems to be the signal from heating only that it’s ignoring….. Any thoughts? I’d really appreciate any pointers you could give me….
Hi Chris,
The first thing to do is test for 230Vac on the SwL (switched live, the call for heat) terminal on the boiler. It should be live when the heating is set to ON. If it isn’t live, that’s the problem! If it is live however, the boiler should light. But as it doesn’t, actually measure the voltage with a meter. It needs to be mains voltage 230-240Vac. Sometimes the three port valve only delivers 70 to 90 Vac in heating mode in which case, replace the diverter valve head.
Hope that helps, Mike