Heatslave 20/25 surge

[Best]

Fire valves are very easily blocked. You need your entire oil line flushed.
It is best to remove the fire valve to flush the open ends of pipe to give good flow for flushing and to avoid a lot of crud just blocking fire valve.
Oil pumps won’t last long when oil line is nearly blocked

 

[SJB060685]

You would get air into system any time its opened. You might of dislodged some crap or an airlock, time will tell. If the pump wasn't bled when it and motor were replaced I dred to think what a FGA would say.

 

[richard3009]

I think the fuel line is spotless by the looks of things no sludge or even discoloured fuel in the filter, doesn't need replacing. Airlocked I'm not convinced you tend to get flame waffle, I reckon that fire valve was half closed and the pump was sucking like buggery for fuel. Every time it shut down on reaching the high temp stat it had time to refill the flexible hose as it would equalise the (pump created vacuum), then the whole scenario starts again.

 

[SJB060685]

Again I'm impressed with your knowledge. You are correct, air in pump can cause an unstable flame, it also wont start at all, it depends on how much air is inside, if it's only partly restricting the pump outlet to pressure line it might as you say waffle, if its fully blocking then you wont get anything through.

 

[SimonG]

Love the smell of kerosene in the morning, not so sure of the taste

 

[richard3009]

Had my fair share of that when the bulkhead 90 valve leaked for weeks before I sussed out where it was from, horrible design, drilled through bulkhead and fitted an inline hose valve, sorted.

 

[SJB060685]

How far away is the fire valve? I've come across crushed lines or kinked hoses a few times where burner ignites, runs then flame goes out and then by the time it tries to ignite again enough fuel has come through for ignition. If your burner is coming up to temp and then shutting down through stat then I imagine it's at least a couple metres

 

[richard3009]

When I say its shutting down via the stat Im talking about the heating phial as designed, so my bolier water is circulating around the rad circuit trying to reach room stat target, if my circulation water reaches the boiler heater stat target, it will shut down the burner but keep the diverter in heat position. As for the fire valve outside i need to check where its stat phial is parked it may be touching a pipe

 

[SJB060685]

The phial for your fire valve should be clipped above the burner. Its purpose is to protect the flexi, although if there was a fire hundreds of degrees c will be reached in seconds. And yes if its resting against a hot surface then you will getting nuisance tripping.

 

[richard3009]

it should stop 1200 litres of kerosene being added to a runaway fire, anyway thanks for the help just pleased to have it working as designed. A faulty boiler in winter is a bloody nightmare, always learning and just about understand this model inside out.