Intermittent Boiler Issue

[fixitflav]

Agree they normally fail to OC but have seen the valves sticking intermittently, not common but can happen

OP said the pump runs, but unless I missed it he hasn't confirmed power is getting to the boiler when heat called.

 

[ianmcd]

OP said the pump runs, but unless I missed it he hasn't confirmed power is getting to the boiler when heat called.

he said in his first post that the fan is running so the switched live is getting power at the boiler

 

[fixitflav]

he said in his first post that the fan is running so the switched live is getting power at the boiler

OK missed that

 

[picasso]

Its possibly the gas meter governor sticking, usually shows its self as boiler lock out first thing in the morning.

 

[Grumpy Gasman]

Potterton Profile will continue the ignition sequence with or without a gas supply.
I would be looking @ a controls issue.

 

[Iainmcr]

Potterton Profile will continue the ignition sequence with or without a gas supply.
I would be looking @ a controls issue.

It's now not switching on sometimes in the morning and sometimes in the evening which totally *******s up my theory about the cold getting to the gas valves!

So taking it I've already changed the controller and that its affecting both HW & CH we must be looking at the PCB?

 

[ianmcd]

Potterton Profile will continue the ignition sequence with or without a gas supply.
I would be looking @ a controls issue.

but the fan and pump are both running

 

[Grumpy Gasman]

If I manually boost or advance the timer then the boiler fires up ans the system is fine.

Now the odd thing is that both CH and HW come on automatically in the evening but not mornings.

 

[fixitflav]

but the fan and pump are both running

How about the ignition system - transformer or electrode or detection electrode? (before I get jumped on - I'm not suggesting the OP investigates it himself, if he doesn't feel inclined).

 

[Grumpy Gasman]

How about the ignition system - transformer or electrode or detection electrode? (before I get jumped on - I'm not suggesting the OP investigates it himself, if he doesn't feel inclined).

Potterton Profile is the positive pressure type, the OP should not be encouraged to remove the front case for obvious reasons.
The Profile utilises a single ignition/rec probe.

 

[fixitflav]

Potterton Profile is the positive pressure type, the OP should not be encouraged to remove the front case for obvious reasons.
The Profile utilises a single ignition/rec probe.

Thanks for the clarification. I commented on the OP not doing the checks himself.