Valiant boiler

How old is the boiler? is it still under warranty? if not it could be the PCB at fault, but without standing in front of it and running a few tests Im not going to say it defiantly is. Your best option is if its under warranty get Valliant in if its not get in a local Gas Safe engineer. Have a look on the Vaillant site for their registered installers who have had training on their boilers.

 

If its not the PCB thats quite an expensive mis-diagnosis, as a PCB cannot be returned once the seal has been broken on the packaging.

 

the pcb is the brains of the boiler, its very complex it will tell the boiler to go or not for all different reasons, like dave says its a very costly mistake to just guess at things, and don't call hin shirley

 

ok further explaination why I've got a bit of time,
power goes to the pcb, its sends power to the pump and fan, if they run and it knows by means of sensors or air pressure switches or micro switches sending messages back to the pcb it goes to the next stage, it opens the pilot and igniter, that sends another message back whether or not to open the gas valve,
if any of those conponents or sensors or microswitches are faulty the boiler wont work, so you could end up buying a pcb when it could be a sensor,

sensor= £4
pcb= £180

make sence now ?

 

Well it sounds like the pcb, however, you need to be much more thorough in your investigation. How do you know you have 240v at the pcb, did you open it up and put a meter across the terminals? Is there a good connection to the pcb? I only query your logic because you changed a perfectly good fuse (your words) and seem surprised that the boiler still didn't work.

Boards rarely fail to be fair so you need to have a good look round the boiler to see if there is an external problem that has caused the board to fail. Start with the 240v bits, pump etc. And be careful, 240v across your dangly bits could be painful.........

 

Use a continuity meter to check you have continuity between the glass fuse.

 

I don't know much about boilers.

If the fuse is intact and you have 240V coming through.

Disconnect the supply and removed the PCB, check the tracks top and bottom to see if any have burnt out or any damaged components?

 

Hi Haverproblem, If you know what you are doing you can check the 240v side of the pcb and the dc outputs as well. But what I'm trying to tell you is that if you have absolutely nothing working in the boiler at all (which seems to be your case) it will probably be something really obvious (like a broken wire) or something really complex (like an external component or control) that has caused the fault. So by replacing the board without knowing what the problem is just may end up by blowing your replacement pcb as well.

So check the obvious, if you cannot find anything then get your wallet out and call in a pro.

I'm sceptical about you fault finding level to be honest, just why did you change the fuse 3x. Did the new one blow each time you replaced it? In which case it was trying to tell you something (earth fault?). So you will probably be better off calling in the pros, sorry. Valliant fixed price fix used to be about £350 but check their t's and c's first, I have a feeling that excluded the pcb.

Its Friday, the call of the pub cannot be resisted any more. Catch up tomorrow.

 

does the case form the seal on the combustion chamber on theses? if so you not allowed to remove it in the eyes of the law, be carefull what your doing. if you change the pcb you will want to have the boiler commissioned/ tested by a competent person. so call in an engineer in, protect your family and your neighbours.