Rayburn G33 on its last legs....

[HaventAClue]

I've resigned myself to the fact that I'm going to have to replace this relic as some parts are no longer available but I'm trying to buy myself a bit more time.
Does anyone have any ideas what might be causing the following:
* Boiler burner does not automatically fire up on any setting (Low to 5).
* FFD has recently been replaced so this isn't the problem
* Pilot light big and bright
* BUT - burner does fire up when pump to Rads is switched on. Does not heat hot water though.

Its been suggested it might be thermostat but as this is impossible to replace I'm hoping it isn't.

[gasman]

1. There could be a fault on the two port valve in the cylinder cupboard. Power comes from the programmer to the dual cylinder stat to the two port vavles that tells the pump to run and then the boiler to fire up. So if it only fires up when the heating is on but no hot water then then it may be the 2 port is faulty. Or the cylinder stat. ( i am assuming that you have an 'S' Plan system )

2. FFD Obviousley working fine or there would not be a pilot light on.

3. Pilot Light may be starved of Oxygen and is reaching out searching for it, hence been big and bright. Is there enough ventilation and the air vents not obstructed or clogged up ???