Potterton Kingfisher boiler keeps relighting

[apna]

Hi all,

Newbie here and I was hoping someone can help. We have a problem with our Potterton Kingfisher MF CF 100 that we can't seem to fix. After around 10 minutes once the boiler has fired up, the flame goes out and the boiler relights. It then continuously does this after every minute. The radiators and water are getting hot but not sure why the boiler flame is going and relighting all the time. The boiler never goes to lockout or we have to reset. We do have a kettling noise but we have been told by the boilerman this is just scale in the boiler.

Here is a link to a video showing the problem.

Here's what has been done:

1. Fernox F3 cleaner (done twice), radiators drained and Fernox F1 Inhibitor added
2. Replaced pump
3. New 3 valve head
4. New boiler overheat thermostat
5. New boiler thermistor/temperature sensor (with new thermal paste)
6. New boiler PCB (from previously working boiler)
7. Replaced gas valve
8. Replaced electrode lead

The problem is still happening.

The pressure switch and the flue spillage stat have not been replaced.

Any pointers of what else can be wrong. What would be telling the boiler to extinguish the flame and relight? Any help or advice would be much appreciated.

 

[muggles]

If it's kettling, then the heat exchanger hasn't been properly cleaned and the boiler is likely to be overheating due to poor circulation. You might need to use a stronger cleaner like F5 or Kamco FX2 in combination with a powerflushing machine in order to achieve the desired result

 

[apna]

Thanks Andrew. We were trying to avoid getting a powerflush done as all the rads seem to be heating correctly. Can you use those products without powerflushing (we have a open vented system)?

 

[muggles]

You can just have the boiler flushed and not the radiators...assuming that is the problem of course, which it may not be. I am, after all, sat at a computer looking at a video, and what you really need is a competent boiler engineer with some test equipment who can provide you with a correct diagnosis and subsequent repair. What you seem to have had so far is a parts changing chancer who has been launching random parts at your boiler in the vague hope that it might make it better. If you can't find anyone who is any good, then Baxi do offer a fixed price repair option, although it's expensive.

 

[apna]

Yes that's the problem, we're struggling to find someone who can help. Based on recommendations, we have had a few boiler engineers round and they've scratched their heads, recommended parts to change or suggest fitting a new boiler system which we can't do at the moment. I've also rang Baxi and they said they will not send an engineer as the boiler is so old.

If anyone can recommend someone in the Berkshire area that have worked with these boilers and can help with the diagnosis, please let me know.

 

[muggles]

Berkshire is 80 miles across! What's your nearest town?

 

[apna]

Slough

 

[Ihavenojob]

Is the noise I can hear the fan ? If so it seems the air pressure switch is dropping out, could be a split in the APS tube, or failing APS.Can you hear if it starts to spark immediately it cuts out ?, if it does then it could be a gas valve solenoid cutting out when hot.

 

[muggles]

@Mike_W is your man
http://www.mwtheplumber.co.uk/

 

[apna]

Is the noise I can hear the fan ? If so it seems the air pressure switch is dropping out, could be a split in the APS tube, or failing APS.Can you hear if it starts to spark immediately it cuts out ?, if it does then it could be a gas valve solenoid cutting out when hot.

Yes it's the fan. I'll check that tonight.

 

[apna]

Thanks I'll reach out. If anyone else is based round Slough, let me know.

 

[ADMO]

Hi Apna.... I have exactly the same problem as shown in your video. I have already changed the electronic PCB. But it is still the same.
How did you manage to fix this ?

 

[ianmcd]

please start your own post

 

[ADMO]

Many Thanks Ian.
I will start my own post.
Is there a way of contacting "apna" by email or so.
Many Thanks.

 

[Nige F]

I found another guy ( Mike ) www.miketheboilerman.com website with contact etc. Even though the thread is old he fixes OLD boilers.