Potterton Suprima fans

Suprima flue fans

When a Potterton Suprima boiler fails, four times out of five it will be the PCB, or the printed circuit board. But of the remaining one-in-five breakdowns the flue fan will usually be the culprit, with the status light on the boiler control panel flashing red, three flashes per second. (For info about the other of Suprima faults see my separate site suprima-repairs.co.uk) 

Now there are about six different flue fans fitted to the various models of Potterton Suprima and getting the right one from the merchant can be quite a problem for the repair technician. They all look superficially identical but there are differences in the screw holes in the fixing plate, in the shape of the fixing plate, and in the fan motor power. It is important to get the right fan as firstly the wrong one probably won’t fit, but even if it does fit the motor power might be wrong and combustion and/or fuel efficiency could be affected. So my advice is always take the old fan along with you to the merchant and compare it in detail with the new fan the merchant is offering you. 

There is also a thriving market in cloned fans and reconditioned fans. The clones on the market are best avoided in my opinion as all those I’ve ever seen have an over-sized motor which will burn a little more electricity than the right fan, and possibly propel a little more ‘excess air’ through the heat exchanger, reducing the thermal efficiency of the boiler. I don’t see any safety risk in this but I’d expect the boiler to burn slightly more gas than it used to before fitting the ‘clone’ fan.

Recon fans however are a different animal. It’s nearly always the motor bearings that fail and the big players in the recon market fit new bearings to repair failed fans, and re-spray them to look like new. And in most cases they ARE as good as new so I’m entirely happy to fit them and they seem to last just as long as brand new fans.

A third possibility if you are a capable engineer is to replace the bearings in your own failed fan, assuming that’s the problem with it. Its not that difficult with the decent workshop facilities you probably already have in your garage or shed! It’s a standard size ball race bearing freely available on the net, or there are usually one or two traders on Ebay selling the right size bearing as a kit for about a fiver. The kit is two ball races and a leaflet explaining how to dismantle the fan and fit them. Beware though, I’ve done a few and they take quite a while so nowadays I buy and fit either new fans or professionally reconditioned. 

A brand new fan, ready for installation

An old, failed fan removed from a Suprima 

A bearing set comprising two ball races, with a £1 coin for scale.