apollo 30

[safetyman1]

Hi all i have a apollo 15/30 boiler no fan . have changed thermo couple . gas valve working overheat trip change. the boiler lights up and fires up but if the central heating radiator is on it goes out if i turn off central heating and just leave water on auto pilot light stays on and system works ok as soon as central heating put back on auto soon after heating going on then the system shuts down. any ideas

 

[ChrisR]

Sludge. Or lack of circulation for some other reason like tired/blocked pump.
Does the boiler have a High - Low switch? If so try Low.

 

[Agile]

On older and less well cleaned systems, most of these boilers will not work well on the "high" setting.

Tony