Ideal Icos HE15 starts then flame outs?

[idealnumber1]

if you get the boiler to light,then it goes off the detection lead may well be faulty,as the condense pipe also may be blocked.
TRY THE BLACK RUBBER LEAD ON THE RIGHT HAND SIDE IT COMES OFF THE ELECTRODE OCCASIONALLY,JUST PUSH IT BACK ON

 

[shambolic]

Have had the detection lead come loose at molex at pcb.
Tony an overheat situation can also cause an LF fault. If the boiler has 3 overheats during the one on period it will cut power to the gvl which means the next time it come on you get the LF. The diagnostic software can show this as you will have several OHeat codes followed by LF. It also gives the total amount of ignitions from new and failures and lockouts. The boiler only locks out on 3rd attempt. This could show a problem with the ignition probe as I have had a couple intermittently shorting at bottom of electrode not top. So if you have had 2000 ignitions 100 failures and 10 lockouts but no overheat codes it narrows it down to ignition, gas, condens line or flue. Back to original poster have you tried the gas valve as if out of cal you will get wrong air gas mixture.

 

[Grahamj]

Once again thanks for the replies,

This seems to be something to do with the Flame detection electrode. This one was replaced at the end of Jan when this fault first started.
After taking it out cleaning and replacing it the boiler started straight away. It has stayed working for about 24 hours over the weekend then stopped, showing the LF code again. Took the electrode out again and did the same again and the boiler starts up again!!!!! The electrode is showing signs of arching on the ceramic near to the retaining flange. This would make the site of the arching just inside the wall of the combustion chamber.

Regards......

 

[Agile]

But the flame detection does not have any significant voltage to cause visible arcing damage.

But it does seem to be the correct focus of attention from what we have advised you as well as what your own experiments have shown.

Tony

 

[hect]

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.

Question - where exactly have you repositioned the spark generator to??

 

[Grahamj]

Thanks for the reply,

I believe what he meant was refitted it and checked the gap of the electrode. As it happens it has been working OK now. Apart from the noises from the boiler when lit.

Loud bangs and groaning noises, also the sounds of what sounds like the air bubbles in an aquarium when the burner is lit. Stops as soon as you turn it off.

It has recently had X400 in it to flush the system out. The water was clean when it was drained after a couple of days. Refilled with X200 and X100 and seems worse!! As they say it never rains only poors!!!

 

[hect]

Noise in boilers is for 2 reasons - bad gas/air mix, or kettling........

 

[Agile]

I have rather lost tract of this one but is it working most of the time OK now?

A little tip for the independents!

If you are faced with a premix with ignition electrodes which are a little way out of cal, usually 4 mm = £1 coin. then dont just try to bend them as they are likely to snap!

Instead, heat them up in your blowlamp until a cherry red and then they will bend easily. Always support the lower part and NEVER bend against the ceramic.

Thats only for independents who dont have a van full of free spares to change willy nilly.

"Cherry red" is an indication for temperature of steel before quenching for heat treatment as learnt on workshop practices which they used to do a long time ago when my grandfather was doing his early training.

Grandfather gave me a 12v battery charger which he had made using a home wound transformer which gave about 10A @ 12 v. It originally had an interesting thermionic rectifier valve with a 3v filiament and two carbon anodes and would give about 3-4 amps.

Unfortunately he did not know that it needed about 15v at the transformer to overcome the losses in the rectifier and wiring to give the full potential charging current to the battery. I supplied it with 260v from an autotransformer to overcome that problem and added a silicon rect to give up to 10A charge current.

Tony

 

[idealnumber1]

Loud bangs and groaning noises, also the sounds of what sounds like the air bubbles in an aquarium when the burner is lit. Stops as soon as you turn it off

sounds as though you have a blocked condense pipe

 

[maccabe]

Loud bangs and groaning noises, also the sounds of what sounds like the air bubbles in an aquarium when the burner is lit. Stops as soon as you turn it off.

I know this is an old post but it may help someone else. The noises described above are exactly what we had... this system hadn't been serviced in 3 years. The condensate S Pipe and the drain into it were pretty well jammed. I was amazed it had worked at all, but on it's final day after receiving the LF key I tried starting it up and went outside to listen to the exhaust and that's what it sounded like. From inside the house it would shudder and bang. Cleaning the condensate S pipe sorted it out. And Heat returned to our freezing home (wife's word's)

 

[shambolic]

Your bloody heat exchanger is full of water as was advised 2 pages ago.
The condense will be blocked either at the S trap under the boiler or where it goes into your drain.
First disconnect the black hose where it joins the condense line(with a bucket handy) if the water comes out then all well and good the blockage is on the condense further down.
If not this is where it gets fun as it is in the s trap which will go everywhere when you try to take it out.
The easiest way to remove this is buy a new one then use a cordless drill to drill a couple of holes in the base of the old one (put a bucket under) as this will control the water coming out saving the electrics.
Just think if you had done this a while back it would have saved a pcb etc as it sounds as if it was always a partial blockage on the condense filling up then slowly draining off when boiler in fault condition.
Only hope its not took out or done any damage to insulation panels in the hex!!

 

[shambolic]

Just noticed this is months old