Fan Flue Boiler Issues

AvonAndy

Hi,

I have an Optia FF50 thats playing up.

Regardless of mode, HW or CH, the pilot comes on, the flue fan runs, the boiler lights up and away we go, but then after a short time, typically <10 minutes, it shuts down and won’t relight.

The overheat thermostat hasn’t popped out and I don’t think the outlet pipe gets hot enough to trip the limit thermostat as I can comfortably hold the pipe.

When it started playing up and wouldn’t stay on I thought it was the control board so as I’m comfortable with changing that I did, but it made no difference. It was then that I noticed that if I left the boiler switched off for an hour or so it would re-light, but then just repeat the above cycle.

There’s a good blast of hot air coming out the flue when it’s running so I assume the fan and pressure switch are good, but what’s causing it to turn off?

Also the temperature control seems to make no difference; it can be set at 1 or 6, but doesn’t make the boiler stay on for any longer when it’s running and when it stops it’s like someone has just cut off the gas...

And finally once it’s ‘out’ the fan keeps running and the spark gap on the controller is discharging so the ignition appears to be working, but no relight.

The thing is I just need to keep this old boiler going for another season rather than replace it , so can anyone give me an idea as to what’s wrong and an approximate cost for a gas engineer to fix it?

I don’t want to throw good money after bad, but I can’t afford a new boiler at the moment...


Thanks much

southcoastrgi

You needed a RGI to replace the pcb & if you had you might not have wasted your money on a board you didn't possibly need

AvonAndy

Thank you SouthCoast RGI for your reply and of course you are absolutely correct, but when the boiler failed initially I used the fault finding flow chart for this boiler to diagnose the issue which suggested replacing the controller pcb.

Given the cost of a replacement was less than calling out an RGI I took the decision to give this try which didn’t work.

I guess the reason for posting was two fold; to understand what the approximate cost would be to repair the boiler given the symptoms or if indeed the boiler can be repaired (appreciating that diagnosing a problem remotely based on an uniformed description may not be possible) and also to help others avoid my uninformed attempts at a repair.

As I’m sure you can appreciate the intent of the site is to help the home owner save money and as I did not disassemble the boiler, the control pcb is easily accessible, I felt this was a useful post.

JimmyChanga

Pipe doesn't have to get warm enough if the temp sensor is faulty. Have you checked it with a multimeter?

bris

AvonAndy wrote: »

As I’m sure you can appreciate the intent of the site is to help the home owner save money

But it would be foolish for the ones who know a bit about boilers giving out information that could lead to you killing yourself and your family whilst you sleep.


A bit of an exaggeration? Or is it. DIY and boilers don't make a good combination, get the experts in.

AvonAndy

I booked an RGI who called today and fixed my boiler.

A major part was replaced, which I would not have touched even if the fault was diagnosed, and he carried out the necessary safety checks afterwards.

Heating and hot water is now working and if the system fails again I will call in the professionals.

The cost was reasonable and service prompt.

Thanks to all who commented.

Le_Kirk

A major part was replaced

Ummm. errr, thinks. No I give in, any clues please?