hi, new to this so appreciate any help.have a warmflow boiler approx 6 years old fitted on my houseboat. burner is an rdb2.2 21-26. has been good and runs on kerosene or red diesel quite happily. developed a fault recently when recommisioning for the winter. having primed up new fuel, the burner will ignite then immediately go out, re ignite then go out, sometimes burns for a couple of seconds, sometimes slightly more. if left it will cycle like this until the burn becomes longer and eventually will function normally.once lit it will cut in and out on the thermostat normally.this seems to be heat related as though it needs to warm up before it will hold in, like an old car with a choke.fuel is good, pump appears to function ok, although has had some crap through it in its life,solenoid and ignition appear to be ok,any ideas as i don,t want to leave it on till march just to keep it warm!thanks for help.