Central Heating Stopped working??

[harty084]

The heating came on yesterday and went off as normal after 2 hours, so I went to put it back on as it was cold but it wouldn't fire up.

I therefore went round the house and bled all the rads as the pipes had been banging recently and got some air out, plus this also made the pipes bang a bit.

So went to restart the boiler and it tries to fire up, then just trips out. I have a full tank of heating oil and have bled the boiler on start up, but it still just trips out. Boiler is a Grant Euroflame 70/90, I have oil in the tank and water in the system.

I have just tried to start it again now, the boiler clicks, the pipes bang a bit, it tries to fire then cuts out. Any suggestions please. A friend has suggested the oil/fuel pump??

Would an airlock cause the boiler not to fire up?

 

[MANDATE]

Can't see how a air lock can prevent boiler from firing up.
A pocket of air in the pipe work can get compressed and prevent circulation and while bleeding radiators may remove air from radiators' it's not going to remove a air lock. Also if the heating has been running for 2 hours can't see how you have a air lock.
The two basic requirements for your boiler to fire up are (a) oil being discharged from the nozzle and (b) electronic sparking across electrodes in order to ignite the oil spray.
Can you see or verify that sparking is taking place?
Is a flame actually established and then goes out or is a flame not established at all.
Can you verify if the nozzle is wet with oil or dry.
There are a number of things that relate to lack of oil at nozzle.
Faulty Electric motor for turning pump. worn pump, blocked nozzle and also faulty solenoid on pump. Faulty control box etc.
If you're not in a position to check all the above, then It's time to call in the engineer me thinks.

 

[Whitespirit66]

Remove slotted cap from circulation pump. Turn heating on. Push screwdriver into hole in pump where cap was, and see if pump is turning.

 

[harty084]

Nozzle is wet, have cleaned the electrodes and checked the gap, cleaned the pump filter and yes the CH circ pump is turning.

Have just tried again and it clicks, makes a constant humming noise, then makes another noise, then trips out, meanwhile the pipes are banging for about 15 seconds??

 

[MANDATE]

Looks like lack of sparking then! To me that could be faulty transformer or control box.
In the past I've bench tested transformer assembled to electrodes to verify operation before fitting.
If you could verify transformer is OK then that leaves the control box.

I have run my boiler from cold for 10 mins without control box. Did this using three separate switched leads along the following lines.
(1)switch on motor/pump
(2) switch on transformer/electrodes
(3) switch on solenoid (boiler lights)
(4) switch off transformer/electrodes.

Of course you can test each separately

 

[nogoodatfaultfinding]

Which Boiler?
Is the fan running?

 

[harty084]

No fan not running

It's a Grant Euroflame 70/90
http://www.grantuk.com/userfiles/download_29.pdf

 

[casius66]

Could be oil pump or motor bearings causing it to stick (the humming) possibly capacitor.
You could try to remove the oil pump, if this something you're confident to do, and check whether the shaft is tight when turning by hand (or leaking which could also cause motor bearings to fail).

 

[harty084]

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Have taken everything apart again. Have checked the fuel pump and it turns freely, have cleaned the photocell?

I'm not sure that it is the pump as the motor doesn't appear to turn over either, see this vid

 

[MANDATE]

I think you need to prove that transformer is OK and produces spark at electrodes
How far forward of the nozzle is the electrodes. from the photo the position of the electrodes seems way out from specification.

 

[harty084]

I removed the electrodes to clean the nozzle hence them not looking right. I've reset the gap also since then.

I don't do electrics so am a bit stuck on that side !

 

[nogoodatfaultfinding]

No fan not running

It's a Grant Euroflame 70/90
http://www.grantuk.com/userfiles/download_29.pdf[/QUOTE]

Have you tested the voltage at the fan?

 

[MANDATE]

Afraid your'e at a disadvantage if you don't do electrics!
The motor, the transformer and pump solenoid can all be tested separately.
When you know they all function individually and you can test run boiler, you know any problems are related to the control box/photo cell.
From your video Do I take it the motor aint running.
I had considered the motor must be turning the pump in order for the nozzle to be wet, which would also indicate the solenoid must be opening.
There is of course the condition of the pump. If is well worn it may not be delivering at the correct pressure. (Mine was in that situation once, although ran better after oil tank was re-filled and it cost £10 for a gauge to find the source of problem)
Again if motor is suspect, it needs testing without control box, any buzzing would indicate faulty capacitor.

 

[harty084]

All sorted, it was the capacitor. Thanks for all the advice and help guys