Fluctuating (pulsing) oil aga burner flame

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Fluctuating (pulsing) oil aga burner flame

Postby SimonT on Wed Oct 05, 2011 8:09 am

Hello,

I am hoping someone here might have some experience of this. I'm a bit stuck and would really would appreciate some help.

I have recently bought a house installed with a two oven oil burning Aga (vaporising). The burner burner flame constantly fluctuates. It's on a regular 1.5/2 second pulse cycle and varies between 1.5" above the height of the sleeve to about level with the sleeve. Other than that the flame looks normal (blue with orange/yellow tips).

The house had been empty for two years when I bought it so I had the flue swept and an engineer round to service and commission the Aga and the Camray 5 oil boiler. He left effectively scratching his head, so I am hoping that there might be someone here with more experience of matters Aga who might help me discover why the flame does not burn evenly.

These are the salient facts about that I am aware of:

Chimney has been swept and certified OK by sweep. Flue has a pot with a steel raised cover on top (the normal thing to stop wind and/or birds). It's a pretty straight run from the boiler, a simple as can be really.
Flame pulses regularly whether there is wind outside or none at all.
The Aga comes equipped with a BM Control Box which looks like it used to have an electric top fitted but which is not there now (although the disconnected thermostat is still in the boiler).
The knob on the BM Control Unit is turned right down as far as it will go (any more and it clicks down and shuts off)
The oil supply looks fine, the boiler, which tees of later, works a treat.
Mostly the temperature of the oven is stable at midpoint on the thermometer but can drop after we cook.

I hope that's enough info so I don't waste anyone's time. Any suggestions are very welcome indeed.

Simon
East Sussex
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Re: Fluctuating (pulsing) oil aga burner flame

Postby AGA man on Thu Oct 06, 2011 5:47 pm

I would start with blowing out the pipe from the control box to the burner.
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Re: Fluctuating (pulsing) oil aga burner flame

Postby whiteshadow on Thu Oct 06, 2011 8:03 pm

I've posted a couple of messages on this....I called it 'gasping!'

So far I haven't got rid of it completely, as I think it may have something to do with our bendy long flue - Oscillation
But cleaning all the internal flues and especially the burner shell (brass brush) seemed to help!
.......doesn't seem to happen when the slow oil flow rate is 3.7cc, but I have problems with the temperature now.

Sorry couldn't help more..
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Re: Fluctuating (pulsing) oil aga burner flame

Postby SimonT on Thu Oct 06, 2011 9:17 pm

Cheers chaps. Flue is as simple and direct as can be and clean too and I hope the engineer who serviced/commissioned the cooker would have cleaned the sleeve if it needed it so I'll start with the easy one and blow out the oil line.

I am perplexed by just how regular this pulsing is. The sound reminds me of Dr Who's tardis.
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Re: Fluctuating (pulsing) oil aga burner flame

Postby john on Fri Oct 07, 2011 7:41 pm

My post in the adjacent thread applies here !
You are running at a fixed setting which may be in the "breathing" range.
Turn it down low and I suspect the noise will disappear.
Turn it up high and I suspect that it will be similarly quiet .
If so, then you may reinstate the normal auto control with stat and electric head and your breathing / gasping cooker will be tolerably quiet :D
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Re: Fluctuating (pulsing) oil aga burner flame

Postby SimonT on Sat Oct 08, 2011 7:27 am

Thanks for this John.

Having spent last night checking the oil flow (pipes and filters) I too am beginning to suspect that the key to the problem lies with the BM Control Unit. As I stated the thing looks like it used to have an electric top, but it has been removed by the last owners. The engineer who came round to service the Aga seemed reluctant to mess around with the high and low settings on the BM valve but did provide me with a short instruction and some advice. I am tempted to have a go at adjusting the grub screws myself. (I presume this is what you mean by "turn it down low", "turn it up high" John?). Even more so when I saw this web site: www.agadiyservice.co.uk, where I can buy servicing instructions. I am an ex (Corgi registered) heating engineer so boilers do not scare me, although I know little about oil (but knowledge is increasing daily!).

My concerns are:

1) If I do decide to take on the administration and servicing of my Aga will I need expensive specialist tools?
2) Could my BM Control Unit be faulty and require replacing, rather than adjusting? What symptoms do faulty BM Control Units exhibit?

and the biggy...

3) Why should I need an electric top? I have been looking at a friends Aga which does not have an electric top. They have no complaints about the way it works. (Caveat, their Aga might not have been a vapourising sort - -I do not understand the import of vapourising yet).

Thanks for help so far. I am very grateful.

Simon
East Sussex
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Re: Fluctuating (pulsing) oil aga burner flame

Postby AGA man on Sat Oct 08, 2011 8:32 am

I would be reluctant to start turning screws especially if it is reaching temp as you may introduce another problem.If the Aga is turned off and cold take the burner out remove the feed pipe(bundy tube) from the burner turn the elbow around and connect the bundy tube back onto the elbow so it can drip into a container and see how it drips, I had one where the oil would drip really fast then stop then really fast so it was not constant,blowing out the pipe from the box to the burner either moved something or when refilling moved air out of the pipe, but there are some Aga's about that do this to some extent and never found out a way to cure
As far as buying the servicing book all I will say is everything that you could write about how to set up a vaporising burner 5 different people would tell you 5 different ways and they could all be right, its an art not a science!
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Re: Fluctuating (pulsing) oil aga burner flame

Postby SimonT on Sat Oct 08, 2011 8:42 am

Hmm.. thanks.
It's on now. Might wait for warm spell before switching it off again!

From the hardly legible number written by hand onto the plate on the inside of the burner door it looks like it might be the type with a boiler (OCB 90). It's not plumbed in though an it's fitted into the chimney breast in such a way that I have no access whatsoever to the back and sides so cannot see if there are tappings.

I'm beginning to have a queezy feeling about this appliance. Its hard to believe just how much oil it's used since the engineer commissioned only a few days ago.

Simon
East Sussex
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Re: Fluctuating (pulsing) oil aga burner flame

Postby SimonT on Wed Oct 26, 2011 5:20 am

Hello again,

Have not got much further with this issue. Burner flame still fluctuates, Aga is at right temperature but oil usage high and kitchen generally far too hot. :<

I've tried to find a engineer that has done the Aga course but there do not seem to be any in my part of the world and Aga themselves don't cover the area and their technical help centre is much less than forthcoming.

So I am left to stumble along myself.

I have become aware that there are two types of BM control valve, a manual version and an automatic version. How can I tell which mine is? As I stated before my Aga used to be fitted with an electric top but it looks like it was removed before I took over the property.

Again, any help very appreciated.

Simon
East Sussex
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Re: Fluctuating (pulsing) oil aga burner flame

Postby john on Wed Oct 26, 2011 8:38 pm

A manual valve has a grey control knob on the top which you can turn up / down to regulate the heat.
The auto version has just pin sticking up in the centre of the top . (presuming as you describe the electric top has been removed)

If an electric top has been removed and the temperature is still Ok ( and it is not the manual valve ) it sounds like the firing rate has been regulated to mid range to control the temperature .
Mid range does sometimes exhibit a pulsing flame (sounds like you have someone heavy breathing in the kitchen)
You may be able to regulate the fire up or down to get outside the pulsing range, otherwise it may be better to re-instate the full auto control system.
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Re: Fluctuating (pulsing) oil aga burner flame

Postby SimonT on Thu Oct 27, 2011 7:42 am

Thanks John.

It's got grey knob and overall looks quite newish so I suspect that the old owner got a new manual control valve installed when their electric top failed. The knob is set to its minimum. I am beginning to think that it might be best for me to track down someone who is able to check and calibrate the control valve oil flow. I think this task is probably beyond me (and might require specialist tools anyway).

Simon
East Sussex
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Re: Fluctuating (pulsing) oil aga burner flame

Postby Joe Griffin on Thu Oct 27, 2011 9:22 am

SimonT wrote:
I am beginning to think that it might be best for me to track down someone who is able to check and calibrate the control valve oil flow. I think this task is probably beyond me (and might require specialist tools anyway).

Simon
East Sussex


Not sure whereabouts in East Sussex you are, Simon, but when we had our oil-burner (now replaced by a 30 amp in our rebuilt house), we used to use SBS from Pulborough (only a few miles down the road from us). Their web site is http://www.southdownboilerservices.co.uk/ and the guy we used was Kevin Read (he's the son of someone from our village). They are a small, helpful firm and may be able to help. By all means mention our name (the Griffins at Rudgwick).

Good luck,
... Joe
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