Vaillant 242 works for two hours

[kboyd]

Hi there all. I have a problem with my boiler and wondered if you could help. I have a Vaillant 242 and it works fine and heats the place well for about 2 hours. When the boiler stops firing (presumably because it has decided the return is hot enough) it then seems to struggle when it starts back up again.

It either:
1) Fires up, then immediately switches off and then fires up and switches off and so on... in a cycle.

OR

2) It goes to lock out.

In either of these situations, turning it on and off doesn't make any difference. After it has cooled down again (next day), the boiler will start up again fine and work as normal until about 2 hours in when we see this behaviour again.

This is based on only 4 observations because clearly I can only really test this full cycle once a day.

Can anyone give me any pointers about what I should look at? I'm guessing this is temperature related but I'm struggling with the flowchart thingy because it works perfectly initially.

Any help greatly appreciated! Thanks, Ken

 

[Agile]

It could be a PCB fault but most likely to be a combustion/gas aspect which we do not give DIY advice on here.

Usual advice is to get a competent boiler engineer.

Presumably you have not bothered to get the boiler serviced?

Tony

 

[Agile]

It could be a PCB fault but most likely to be a combustion/gas aspect which we do not give DIY advice on here.

Usual advice is to get a competent boiler engineer.

Presumably you have not bothered to get the boiler serviced?

Tony