Ideal Mini HE Full Sequence PCB

[PrenticeBoyofDerry]

Friend of mine ask me to look at an electrical problem with a Mini He.
No power was being displayed at the power lights.
Power was going to the boiler though, on inspection I could see heat damage to two areas on the PCB that controls the ignition, the damage was in two different areas of the PCB, were a set of two and a set of four resistors were/are.

Should I be thinking on advising my friend to replace this PCB and things will be fine or should I be looking for the source of the problem?
How common is this failure/fault?

 

[Agile]

If no lights then the fault will be on the control PCB or supply.

Its normal for the ign PCB to show those discoloured areas.

How have you measured power in?

Has anyone been trying to add a thermostat?

Tony

 

[PrenticeBoyofDerry]

I have measured supply power at the incoming terminals of the boiler. Which was 247V.
There is evidence of extensive heat damage at the full sequence PCB. I have taken photos, but don't really show the full extent of damage, we are talking charcoal black in one area!

 

[Agile]

If you have photos then post them here.

But you said you have no boiler lights at all! They are provided by the left hand control board!

So exactly how did you measure the 247V ?

Tony

 

[PrenticeBoyofDerry]

I measured 247 volts between L and N/E. Using an expensive piece of calibrated kit "Megger 1720 MFT" on the incoming supply terminals within the boiler.
The only thing that is on is the timer/clock but that is operated by back-up.
I will up/download and post pictures for you.
Your help is much appreciated.

 

[PrenticeBoyofDerry]

Images of PCB in question I have circled area and added pointers to burnt areas on first pic, other images are of the same unit.

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Hope this helps!

 

[Agile]

OK, the discoloration on the ign board at back and front is normal.

However there has been a severe arcing to left of RL2 and that will require a replacement PCB.

It is likely to have blown the 1.6A quick blow fuse on the back left of the control PCB under the black plastic cover.

You need to see that fuse has blown and then replace the ign PCB and the fuse.

Tony

 

[PrenticeBoyofDerry]

Just to add the glass fuse in this PCB had not blown as I had tested that after determining supply voltage.
I did look for a fuse on the left hand control PCB but could not see one, so it is covered then.
Would it be possible (I assume it would) to remove the full sequence PCB and replace fuse in control PCB, just to see if the control lights on.
I assume the boiler will light up but not fire up?

Thank you kindly for your help Tony.

 

[delmel]

Totally different, i had a similar problem, turned out the external pump was the fault, it that isn't functioning, the boiler will not either (this was not on your model) but just an added thought.

 

[mfarrow]

The white PCB mounted socket for the connector (I think pin 7, blue wire) has overheated. You can tell by the distortion of the housing at the end and a bit of discolouration of the black plug.

Probably an important neutral, cause bad part/assembly, and has now likely affected the 'female' pin in the loom also. Pull it out and I bet there's not much left.

If it were my boiler I'd be tempted to strip out and hard-wire those connections for that socket directly into the board.

 

[Agile]

The first three connections on connector J2, that is 6,7 and 8 are to the air pressure switch.

So unlikely to have been directly the cause of the charring to the PCB substrate. That is unless the cable to the top of the combustion chamber has been seriously damaged.

The fuse on the control PCB is under a black plastic carrier on top left corner and must be 1.6A quick blow.

I was going to suggest that you remove the plugs to the ign PCB after replacing the control PCB fuse and see if you get the left green light flashing.

Tony

 

[PrenticeBoyofDerry]

Okay I will do that.

 

[PrenticeBoyofDerry]

Problem sorted fitted new FS PCB, the fuse on the control PCB had blown and I also replaced that with 1.6A quick blow glass fuse.
Everything thing now up and running thank you all for your kind help, with a special thanks to Tony.