Oil burner problem

[Digsy]

Hi everyone. This is my first post here so hopefully someone can help.

My oil-fired boiler has developed a problem which is becoming more an more frequent. For information the boiler is fitted with an Ecofla Monoflame Minor 1 burner.

When the burner starts it is supposd to run the motor and fan for a fe seconds to pre-purge the systm before trying to ignite it. Sometime this is not happening. What happens instead is that the burner jus sits there making a buzzing noise. No motor run, no fan - nothing apar from the buzzing. After about ten seconds of this the burner goes int lockout because it has not seen any ignition.

I have found that if I hit the burner assembly fairly hard with my fis I can usually get it to start running.

Also, I've only just really started experimenting but it would appea that the problem is temperature-related. For example, the boiler ha been playing up all weekend but tonight I started running it at settin

3 on the boiler thermostat with the front panel off and it hasn't misse a beat. I have (literally) just turned it up to 6 (maximum setting) an left the front panel off and so far all appears to be OK.

I have done a bit of research myself and the prime suspects seem to b either the motor or the motor capacitor. The fact that the motor won' start makes me think it is the capacitor, but the fact that I can fi it by hitting it makes me think it is the motor getting stuck!

Any thoughts from someone who really knows their stuff?

Thanks in advance

-- Digsy

[emma]

Don't know my stuff, but when our oil boiler was showing the exact same symptoms, and our engineer suggested it was either the motor or the motor capacitor, he suggested we change the motor capacitor first as it was c.=A320 for the capacitor rather than c.=A3150 for the motor. Turned out it was the capacitor :)

[robgraham]

Can't really understand why the capacitor would respond to the well aimed boot. It would seem much more likely to me that a terminal somewhere is not quite tight - the boot would resolve that as would the operation of changing the capacitor as the offending terminal would have been messed about with. Plus this is quite likely to be temperature related. If you've got access I would go round all the connections and check them for tightness.

The other thing I would try would be to get some lubrication into the motor bearings; they could be sticky as you suggest and the kick frees it. It is possible a new capacitor could overcome this by the very fact that it is new and just that little bit more effective. If you're up to changing the capacitor yourself look in Yellow Pages for a local company who do motor rewinds, that's where I got one when I blew up one when messing about with the start timer on another motor.

Rob

[Digsy]

***bump***

Looks like this is almost certainly temperature related.

The burner fired up fine this morning (still turned all the way up still with the front panel off).

I'll leave it a few more days like to see if it carries on working Bear in mind that at the weekend I was having to manually restart i using the "thump" technique about once every hour

-- Digsy

[Digsy]

Ah, cheers Rob. Didn't see your reply until after I posted again.

Yep - I can see what you are saying. Certainly checking the connection would be a good idea and I'll try to do that one evening this week.

Maplins sell motor run capacitors for about £3 each so I just need t get mine off and check what type it is. I believe that the Monoflam Minor 1 motor uses a 3uF

-- Digsy

[John]

Either the motor/capacitor is failing/has failed or the oil pump is stiffening up. There isn't enough Ommph to kick off the rotation. From bitter experience you will find that the last of these you try will be the right one!

the motor start and run capacitors are the cheapest option at around a tenner. work up from there - motor around £80, pump also around £80

the knock or jerk is often enough to get the first movement going to overcome "sticktion". You could of course have a ball in the bearings which has worn or chipped out out spherical and gets stuck sometimes. Remove the motor and rotate it by hand gently to "feel" whats going on. At the same time rotate the oil pump gently it should turn fairly smoothly although it will be stiffer than the motor.

Yep. or both - as the replacement motor comes with a capacitor and if you are having to make a journey to get any parts you need it might be easiest to get a motor straight away. Do try rotating as above first though.

Its always easier to attack these situations with a vanload of spares :-)

[Digsy]

Another bump.

I've been doing some reading up on single-phase AC motors and m symptons are classic for a starter ciruit failure. From what I've rea this can be down to three things (assuming that the motor isn't plai and simple gummed up somehow).

1) Starter capacitor 2) Centrifugal switch 3) Starter windings

(1) Is a simple "replace it and see" job - relatively cheap. (2) Is "motor apart and clean it" issue. (3) Would mean a new motor.

I don't think it's the starter windings because when it starts, i starts up fine. If the starter windings were fried I don't think i would start at all. The centrifugal switch gives a nice combination o an electrical fault that could be fixed by a swift kick so I thin that's my prime suspect for now.

I'll have to take the motor out to look at the capacitor and check th connections so hopefully I'll be able to split the motor casing and ge at / clean the switch at the same time

-- Digsy

[John]

The standard burner motor doesn't have a centrifugal switch. The capacitor remains "in circuit" all the time the motor runs.

[Digsy]

That's good news, then. So it's sort of like a combined start / ru capacitor?

One less thing to check! Hopefully its just the cap

-- Digsy

[Digsy]

Just to colse this off, I fitted a new capacitor a week ago and th

motor has been firing up fine ever since.

Thanks for all the advice :

-- Digsy

[grantmurray]

Hey, I know this is an old post. But it helped me s much with my boiler. Exactly same symptoms. Buzzing no fan, nothing. Changed capacitor. Boom!

Thanks all for this thread.

Saved my life.

Grant > Hi everyone. This is my first post here so hopefully someone can help. >

[Brian Gaff]

Ay' lad they don' t make thems condensers like wot they used to mate. Brian