Combi pilot flame keeps going out

[baxpoti]

whereas the right hand one does nothing.
Is this normal behaviour or are we getting closer to a cause?!?!?

Nail on the head!

 

[Agile]

The flame detection electrode can be a little critical in its positioning. It needs to be about 4-6 mm above the burner.

However, the ignition lockout is a completely different fault from the overheating you described before!

The first thing to check is if the gas valve is set properly on minimum. Put the boiler on a slow flow of water and slowly turn down the DHW temperature control and watch the flame to see if it steadily goes from large to small. Not a terribly scientific test but without measuring the gas pressure the best I can think of at the moment.

Check the resistance for the tip of the flame detection electrode to the PCB connector.

The measure the 1 m resistor on the PCB in series with the detection electrode. They often go high res or o/c.

There are several other things I would like to test but I cannot ask you for gas related checks.

Tony

 

[TECHNI]

YOUR MINIMUM GAS PRESSURE NEEDS RESETTING ITS A VERY COMMON FAULT .GET A SERVICED ASK THE ENGINEER TO CHECK IT .IT SHOULD BE 2.5 MB

 

[corgiman]

YOUR MINIMUM GAS PRESSURE NEEDS RESETTING ITS A VERY COMMON FAULT .GET A SERVICED ASK THE ENGINEER TO CHECK IT .IT SHOULD BE 2.5 MB

turn off your capslock matey

:0

 

[wiffers2003]

So are you saying that the left hand electrode is the ignition (sparking one) and the right hand one is the flame sensor. Also i'm not exactly sure what the definition is of "lockout".
Sorry for my lack of understanding of boiler phrases, this is the first time i have had to look inside one !!!!

I'll measure the distance of the electrodes from the burner this evening as at work at the moment. Do i just bend them both if the distance is too great?

I'll also measure the electrode resistance and if i can find it easy the in-series resistor resistance.

The minimum gas pressure setting sounds a common answer amongst you all. That will be the next step.

thanks again, Carl

 

[wiffers2003]

OK so i checked both electrodes and both are 5mm above the burner and in the flame path.

Then checked the resistance of the both spark & flame detection electrodes, both are short circuit, zero ohms.

I then managed to find the in series resistors on the pcb, there's actually two in series just before the connector for the flame sensing electrode, each of which measured 1MOhm.

I finished off with the slow water test and reduced the temp stat on the boiler front. Couldn't notice any reduction in flame height as i turned it down although its a bit tricky through the small window.

Does this info give you guys any more clues ?!?!?

 

[oakland99]

you seem to be a highly skilled in electrics but sometimes boilers need additional skills , whilst i admire what you've done maybe its time to call an expert otherwise you will be going round in circles,,

as Clint Eastwood once said "a good man knows his limitations"

 

[wiffers2003]

I completely agree and thanks for your words of wisdom.

I just like to make absolutely sure that i've exhausted all the possibilities of an easy fix first.

cheers
Carl

 

[wiffers2003]

Just thought i would give you a quick update.

Since my last post, i have vacuumed inside the boiler including the gas burners, and set the timer so that the boiler has about 6 hrs rest during night as it was on 24hrs before.

Since then it has not locked out once !

So at the moment all is well.

thanks again
Carl

 

[Edin]

Just thought i would give you a quick update.

Since my last post, i have vacuumed inside the boiler including the gas burners, and set the timer so that the boiler has about 6 hrs rest during night as it was on 24hrs before.

Since then it has not locked out once !

So at the moment all is well.

thanks again
Carl