Valliant boiler board

[_ASH_]

Hi Guy's, ive got a valiant boiler & these are prone for the control boards failing, causing the boiler to go into a error state.

When you run the hot tap, it goes into the error state but then when you reset, these work fine until next time.

Im convinced that the problem with the boards are something simple like a relay which would cost considerable less than replacing the complete board at several hundred pounds.

I was wondering if anyone had ever done any work or knows of anything to do with boiler boards?

Many thanks in advance

ASH

[stj]

Re: Valliant boiler board

i ave fixed boiler boards.
it's usually capacitors.
fitting them in a box under a boiler probably doesnt help!

[_ASH_]

Re: Valliant boiler board

Many thanks for the reply.

Very true, you would have thought that there would be a better situation to put a board within a boiler.

Could you give me any ideas to look at?

Many thanks in advance

[stj]

Re: Valliant boiler board

your looking for any signs of yellow liquid or tops not perfectly flat.
also check the soldering on the connectors - the cables put a lot of stress on the joints

[_ASH_]

Re: Valliant boiler board

Many thanks for your reply, ive kept one of the old boards, so ill investigate on that & post any findings.

ASH

[stj]

Re: Valliant boiler board

post a picture

[_ASH_]

Re: Valliant boiler board

Please see below, although upon inspecting, the big black one seems to be slightly bulging, although no leakage, ive peeled the black wrap from the top and it seems to be a sealed (no the pressure cross, if you know what I mean, like on the others).. but I welcome and ideas or suggestions.




Many thanks again

ASH

[stj]

Re: Valliant boiler board

you forgot to upload the picture!

[_ASH_]

Re: Valliant boiler board

I can see the picture..

Please see the links:

http://ash-group.co.uk/ashimages/2.jpg
http://ash-group.co.uk/ashimages/1.jpg

[redwire]

Re: Valliant boiler board

The board shows water damage, rust on the pcb. Something leaked on it.
I would clean it up with isopropyl alcohol and an old toothbrush, gently.

[stj]

Re: Valliant boiler board

sooo - you didnt notice the connector at x22 has burned all the pads off????
the oposing part on the wiring loom needs to be replaced or it will do that to any replacement boards.

[_ASH_]

Re: Valliant boiler board

Nothing is plugged onto the board on the X22, so I didn't think that'd be the problem

Thanks

Ash

[_ASH_]

Re: Valliant boiler board

This is a new board in situ, which has developed the exact same problem


http://ash-group.co.uk/ashimages/3.jpg

Ash

[stj]

Re: Valliant boiler board

how old are these?
i know ignition coils have a lifespan.

[_ASH_]

Re: Valliant boiler board

The newest board is about 12 months old

Thanks

Ash

[stj]

Re: Valliant boiler board

well it's not the coil then.

i suppose if a pump or valve is drawing a lot of current then it could burn the relay contacts faster than usual.

[_ASH_]

Re: Valliant boiler board

You could be onto something, after inspecting a little more of the old board I found this (I believe it to be a relay) which looks like its been warm in places.

Whats everyones thoughts?


https://ibb.co/gw45wJk


https://ibb.co/dQ5WbH2

[sam_sam_sam]

Re: Valliant boiler board

You could be onto something, after inspecting a little more of the old board I found this (I believe it to be a relay) which looks like its been warm in places.

Whats everyones thoughts?


https://ibb.co/gw45wJk


https://ibb.co/dQ5WbH2

Yes they are relay

I would highly recommend that you remove them and test them I would not recommend testing them on the board

If the current is more than 5 amps I can see that it supposedly can handle 8 amps but I can tell you from experience with type of relays contacts are not very good for than about 2 amps if you are lucky

You would have to reverse engineer what relay contacts have the high current on them and reroute them to a contactor that can the current of the heater element

Use a contactor that is rated for at 40 amps yes it would be externally mounted but in the long run would be better

Or

Buy a box of these relays so when they fail to replace them

Where I use to work at we had a CNC machine controller board relay bank that has a similar type of relay and they continually go bad and that what I did I bought them by the case if I remember correctly a case was 24 of them in a tube

I never measured the current on the contacts because this relay had relay socket and it was very easy to replace them

[redwire]

Re: Valliant boiler board

On the second board I see capacitor C708 bent over, hopefully not mashed. It's by the big filter cap/relay at the edge.

Did you clean the flame rod? Common problem here is boiler controller goes into lockout after either seeing an unexpected flame out or it's unable to light up. If the rod is dirty, the controller will see weak or no flame even though it's there.

Another problem I have seen is the board's grounding, the igniter can cause the MCU to crash if the ground to the appliance or mains is not good. In the pic the two ground wires are cable-tied to the ignition cable- which is a bad idea. Keep everything away from it.

I'm also seeing the high-limit switch trip, either due to low flow or the switch just getting old. I have not worked with Valliant but there should be an LED or something to read fault codes when the unit goes into lockout.