Ideal Icos HE15 starts then flame outs?

[Grahamj]

Trying to fix Icos HE15 boiler that will not start up. It started by showing a L F flame error, but after leaving for 24 hours would start up and run for a couple of days then stop again.

Changed the the flame detection electrode after it showed no continuity. This worked fine for 3 weeks then it all started again. Now it will not start at all. It just goes through the cycles. Change the PCB and still nothing.

All the other things...spark generator, gas valve etc have been checked out to be OK.

Any ideas....apart from scrapping it.......

many thanks.

 

[pipshady]

no ideas here, sorry, i shuddered when i read it was an icos!!

 

[mickyg]

blocked condense sump, trap, pipework etc.. probably needs a good clean. Usually the best thing to start with before changing hundreds of parts
are you an engineer or householder?

 

[gas4you]

As above. I would say about 80% of L:F faults are blocked condensate through lack of proper servicing

 

[Grahamj]

Thanks for the replies,

I'm a householder, family member ex central heating engineer.

Condensate trap and heat exchanger cleaned before the bits started to get changed!!

 

[Agile]

Changed the the flame detection electrode after it showed no continuity. This worked fine for 3 weeks then it all started again. Now it will not start at all. It just goes through the cycles. Change the PCB and still nothing.

All the other things...spark generator, gas valve etc have been checked out to be OK.

many thanks.

I would question just how that list have been checked.

If the boiler is not working at all then I am surprised that the "ex-central heating engineer" is not able to find the cause.

Tony

 

[shambolic]

Check inlet pressure. Also the flue connection and the black seal at the top of manifold if not in you get mixing and failed lighting.

 

[Grahamj]

Once again thanks for the replies,

The items were checked by using a multimeter and a manometer. He did say that he only had a voltage of 138 volts at the gas valve and that it should be over 150, but that was after changing the pcb. Is it possible that the new pcb is faulty as well? (Bought from a proper outlet, not round the back of a pub!)

Also that there was a vacuum at the gas valve generated by the fan when it tried to start, then it change to possitve pressure and then the gas stopped. The gas pressure was 21mbr.

Regards

 

[Agile]

Intermittent faults can be very difficult to identify and particularly on that model.

However, any competent boiler engineer should have no problem finding the fault on a boiler which is not working at all.

I often wonder how you would expect an engineer working for Ideal for example to deal with the 6-8 boiler breakdowns they attend every day if they cannot identify faults pretty quickly.

Tony

 

[shambolic]

Once again thanks for the replies,

The items were checked by using a multimeter and a manometer. He did say that he only had a voltage of 138 volts at the gas valve and that it should be over 150, but that was after changing the pcb. Is it possible that the new pcb is faulty as well? (Bought from a proper outlet, not round the back of a pub!)

Also that there was a vacuum at the gas valve generated by the fan when it tried to start, then it change to possitve pressure and then the gas stopped. The gas pressure was 21mbr.

Regards

The voltage at the gas valve should be over 200 volts DC not AC. TEST it AGAIN as it is trying to light and also have a manometer on the inlet and see if it goes down(blips when the boiler is trying to light). Do this with the blue rubber hose disconnected(incase its blocked or has water ingress).
You have spent a lot of money on this already but a fixed price repair from us might be the answer.

 

[shambolic]

Intermittent faults can be very difficult to identify and particularly on that model.

My laptop plugs into the board and gives real time reporting of faults and thermistors and I can also get history of last 20 odd faults which would help to narrow down the prob on intermittent faults.
Nothing worse than walking into job and all is well as you know you will be called back again!

 

[gas4you]

My laptop plugs into the board and gives real time reporting of faults and thermistors and I can also get history of last 20 odd faults which would help to narrow down the prob on intermittent faults.

Can you get me the software and a lead? I would love to have this

OP, was the sump fully cleaned at the same time as the condensate trap, especially the right hand side?

 

[Agile]

Intermittent faults can be very difficult to identify and particularly on that model.

My laptop plugs into the board and gives real time reporting of faults and thermistors and I can also get history of last 20 odd faults which would help to narrow down the prob on intermittent faults.

Does it give any more useful information to help with "LF" faults?

There was an interesting postoing in the CC about a boiler which Ideal went out to a lot of times and then replaced the whole boiler only to have another "LF" three months later!

Tony

 

[Grahamj]

Hi to all, i'm the family ex heating engineer Grahamj spoke about thanks for the replies.

When i first looked at the boiler checked the usual, ie gas at inlet, earthing at various points, etc. At the time the boiler was working intermittently hence leading me to my initial instinct that it was the flame detection electrode. Having replaced that it seemed to work fine.

When the fault happened the second time i looked further into to it removing the fan and burner cleaning the heat exchanger,sump and condensate. Which apart from slime in the condensate was not in bad condition for a 4 year old boiler.

Reading through the fault diagnosis in the manual the next logical part to replace was the PCB, although reluctantly.

Now the boiler is still not working, there is a dip in gas px at the inlet as the boiler tries to start. If standing by the flue terminal then it is possible to hear the spark generator (which has also been tested and re-positioned) a ignition sound is heard also followed by a slight raise in temp but immediately it cuts out.

I admit i am at a loss , its not as if i can actually see whats happening inside the boiler ie the flame path etc but everything is set up correctly. So any more useful ideas would be most welcome... luckily it'll be summer soon!!!

D.

 

[Agile]

If its actually lighting for a few seconds it implies the flame detection is not working.

The flame detector lead is very thin and could have failed. They can also short onto the cover when its in place. Have you measured its continuity and the resistance to chassis as measured at the PCB end?

Have you inspected and cleaned the detection electrode? We are told that sometimes they look and test perfectly but a replacement makes the boiler work.

Tony