Oil Burner - not working

zapata

My central heating oil burner has stopped working. The make of the burner is danfoss and is attached to a poplar90 box. There is oil(kerosene) in the tank (about 10 inches from being empty - measured with a long stick). When I set the timer to constant and press the 'red' reset button on the boiler it makes noise for about 7 seconds and the burner attempts to fire for about 3 seconds. Then it cuts out. After about 25 seconds I can repeat this proceedure.
It was serviced about 6 months ago by a local fella who has since become uncontactable - although he only seemed to clean out the box of the black soot and didn't do much with the burner itself.
Any ideas?
The burner looks to be a few years old (house is about 15 years old) and is located outside in a small purpose-built shed.

Lex Luthor

sounds like you have an air lock....you say there is oil in the tank so it shouldn't have happened but worth bleeding it.

if you go to the burner at the bottom there should be a small screw with an approx 10-12mm hex head. Open this slightly when you start the burner and when the oil starts coming through it, close it immediately. hopefully this resolves, if not let me know and I'll rack my brains even more.

Victor

Is the filter blocked?

zapata

There is oil coming through. I gave the screws a twist and the oil squirted through. I reckon if it's getting this far then the filter should be ok. I may have to call in the experts during the week or else i'll be flying south for the winter. :-)
Here's a pic of the type of burner:

pipers

Clean the photocell.

Lex Luthor

pipers wrote:

Clean the photocell.

Agree with pipers here also....had this problem before now that I think of it.
Also, check if you're getting a spark but be careful..!!!!!!

Lex Luthor

Zap,
I found my manual that came with my oil boiler and have attached a couple of pics for you that might help. Most boilers from different manufacturers are physically the same anyway, so the exploded view might be of help.

I think the sequence of operation when an oil burner kicks in is as follows, but correct me if I'm wrong...

Boiler switched on, thermostat set to request for heat and for the first 6-7 secs, the electrodes get power and start sparking. After this period, the coil (2) gets a signal from the control box (20) to energize and the valve (3) internal to the coil gets pulled open by the magnetic field in the coil. This in turn, lets the oil into the burner through the nozzle (34) by the pump (1) and is ignited by the spark from the electrodes. If the photocell (21) doesn't see a flame then it will send the burner into 'lock-out' which is what happens when the red light comes on the burner.

So from that, there are a number of factors that could cause the burner to go to lock-out.
1) No oil
2) Faulty or dirty photocell
3) Faulty coil or valve
4) Blocked nozzle
5) Faulty pump/motor
6) Failed motor/pump coupling
7) Seized bearing

Once happened to me that the plastic coupling between the motor (8) and the pump (1) had worn, so I was getting no oil pumped into the burner even though everything else was working fine and it caused the burner to go to lock-out.
The fault finding guide is what it is, a Guide.
Best of luck
Tom

KoNiT

as Lex Luthor said.

but get it serviced!

if you go at it yourself, be carefull of the flame....its pretty big!

Lex Luthor

KoNiT wrote:

as Lex Luthor said.

but get it serviced!

if you go at it yourself, be carefull of the flame....its pretty big!

You can check the flame by pulling the burner out a couple of inches and have a look in but always point it away from you.

zapata

Thanks lads, i haven't had a chance to go at it just yet. Very much appreciated. I'll let youse know the result. I also came across this on my quest for knowledge.

Lex Luthor

Just out of curiosity....if the photocell is failed, does anyone know how to check it? Can it be checked like a switch and put a multimeter across the 2 contacts and verify the resistance in the presence & absence of light?

of do you have to have one wire connected into the circuit and measure current through it as the light passes on it?

zapata

Problem solved. Just as pipers suggested, i cleaned the photocell, it was black with soot. Thanks a million. I learned something new and saved a few quid also - happy day. Thanks also Lex.
BTW - I hadn't a clue what the photocell was until i saw a pick here. .

Lex Luthor

zapata wrote:

Problem solved. Just as pipers suggested, i cleaned the photocell, it was black with soot. Thanks a million. I learned something new and saved a few quid also - happy day. Thanks also Lex.
BTW - I hadn't a clue what the photocell was until i saw a pick here. .

Great

andrew767

hi, its a good idea to change the nozzel every year, I have just done that and it may save some fuel. Also if there is soot deposites may be your nozzel is worn.