Low Oil level in Rayburn BM valve?

[MSY]

I wonder if anyone can help me. The oil level in the BM valve on the side of my Rayburn seems to have dropped as it now doesn't see to be high enough to enable the oil to reach the wicks in the burner unit. Oil flow appears fine but the flow stops before it reaches the main part of the burner, stopping just below. I did run out of oil (and had some water in the system) but all is flushed through now and it all seems a bit unusual.

 

[SJB060685]

If water gets into the system then you will have emulsified oil in places. I suspect there is a restriction somewhere causing a lack of flow to/through the needle valve. Any strainers at tank, in-line filters and filter in your BM control valve need to checked again, also if water has corroded anything inside this is likely to be a BM Control replacement, however I suspect it’s just a blockage in this case. You can adjust the oil level in these valves but these are mechanical settings and unless someone has fiddled then I doubt it’s that.Do you have an oil boiler coming off tank as well, if so does that run fine?

 

[SimonG]

Really glad I don't do vapourising units.

 

[SJB060685]

Vaporising burners are easy Simon, although I have no experience with the Rayburn nouvelle.

 

[SimonG]

I'll stick to pressure jet. Aga and Rayburn are up their own backsides. They only like their own people to touch things.

 

[SJB060685]

You’re right there. Rayburn wouldn’t even give me a detailed rundown of the 480k start sequence

 

[Best]

The filter in the control valve needs checked - it normally is ignored.
Also other filters and fire valves for blockages.
But the final fixed pipe to the burner might be carboned up

 

[SJB060685]

The carbon leg blocked will cause a little to no flow to burner Best, however the OP is suggesting that the level in oil control is too low. I’m inclined to believe it’s one of what I mentioned above as the inner workings of these are mechanical as you know and unless riddled with shouldn’t alter. The OP needs to dip the tank again for evidence of water still there, or more. Then he needs to check strainers, in-line filters and the filter into valve as well like you say. Emulsified oil is a milky white colour and should be easy to spot. I once saw a Toby valve with about half in of emulsified oil in the bottom, obviously the fire wasn’t staying lit, I removed control valve and removed all crap, reinstated and away she went.

 

[Best]

Yes, I was thinking the level of oil shouldn’t be caused by the final steel pipe partly blocked. It would just cause slow flow. I just mentioned it as something to be additionally checked out

 

[SJB060685]

Yes I know buddy. The carbon leg could be blocked as well but what is certain is he has a problem before fuel even goes through the metering stem. I have known some older engineers fashion a guard to put over carbon leg or wrap in tin foil to deflect heat away and stop the carbon forming where’s it’s not wanted (I believe the deep well burners are more susceptible to this).
If the OP responds we can take it from there

 

[MSY]

Thanks for these suggestions. The Rayburn was working pretty well before and, as far as I can tell, no adjustments have been made. I have cleaned out all the burner pipework and the narrow slot in the valve unit seems fine. Clean oil is coming through to the burner tray just not high enough. Should the oil level in the BM valve coincide with the level of oil in the burner?

 

[SJB060685]

Yes the level inside the oil control will be matched in the burner.

 

[MSY]

That's what I thought. It seems as if the float valve is not allowing a sufficient depth of oil into the valve. Is there an approximate depth of oil that I might expect? It looks to be about 1 1/4 inches or thereabouts. Could any float valve adjustments have been knocked out of position? As it was ok before I am wary of making any major adjustments to the valve height that might cause issues in the future.

 

[SJB060685]

There is actually two floats which control the needle valve, which is what controls the flow of oil into the valve. Sorry to sound like a t**t, I don’t mean to but you clearly don’t understand this valve do you. Adjusting the control valve height isn’t going to fix your problem. The valve under normal working conditions will always fill to a set line, you can see these indicators inside the oil control valve.

 

[MSY]

Thanks for the detail. The valve is in a fairly tight spot in a dim room so there is not a lot of light about so I have not been able to see the set lines on the side. I'll get a bright torch in there to see if it indeed filling up to there. Are these on the inside rhs?

 

[SJB060685]

If you take the lid off you should see two fill lines, a min and max? I’m assuming the floats are sitting on top of the oil? And not stuck in the air? Whilst there trying pushing the float up and down a few times, I believe air can get trapped in needle valve or some crap and doing this might dislodge it.

 

[MSY]

Thanks. I'll give this a shot (though it'll have to wait a few days unfortunately). Hoping for the best.

 

[SJB060685]

Unless I’m forgetting something then I’m assuming it’s a blockage or airlock of some sort. If you can’t get to the bottom of it yourself then get an engineer out.

 

[MSY]

Many thanks for your advice and help.

 

[SJB060685]

No worries. Let us know what you find