Oil central heating not coming on

[gavinh1]

my oil central heating is not turning on when I turn the thermostat up. It does come on but only when it wants it seems. Hot water works fine.
I replaced my drayton t45 thermostat with a Honeywell t6360b ( I presumed they were interchangeable) and this has made no difference. All used to work fine (for the last 10years) . The programmer is a lifestyle acl lp241. ive have tried all the timer setting with the programmer and it seems nothing I do will make it come on. Any help guys . thanks

 

[gavinh1]

ive had the hot water turned off a while today and just turned it on and the radiators have heated up now.. very strange. does this help anyone help me with what could be the problem part / area. cheers.

 

[Boilerman2]

A bit more info on your system would be useful such as type of motorised valves if fitted, some pics of vital system parts would also help, oh and is your boiler a conventional or combi type?