Warmflow Oil Boiler Help Needed

[grrrrrowler]

Hi All
I hope someone can help me.
I have a warmflow utility 70 oil boiler and a riello rdb pump.
The boiler cuts out every so often and I have to reset it. The first time I reset it it cuts out again after 5 secs or so but the 2nd time it works ok for a couple of hours.
I have bled the pump and also cleaned the photo cell.
Does anyone have any idea what the problem could be please?
Any help would be appreciated.
Many Thanks
Dave

 

[oilhead]

Try the solenoid coil. If you can catch it as soon as it stops, chek resistance on the coil with a multimeter on the 200k range. Chances are it will be open circuit. When it cools down, you will get a circuit again.

 

[oilman]

The coil is unlikely to be the problem on the RDB as all the parts including the pump are Riello, and do not work in the same way as Danfoss pumps where coil breakdown is common.

The oil supply could be the problem, or the photocell, or a worn pump, or stiff motor bearings, or air ingress into the oil line, or combustion setting.

 

[grrrrrowler]

Thanks for your replies.
Is there anything simple I can check - eg filters? If so where would I find them?

Cheers
Dave

 

[grrrrrowler]

Hi All
Quick update - have noticed that the boiler/burner only resets when the thermo is set above 22 degrees.

I have had it on all day at 22 degrees and it is fine.

Does this help shed any light at all?

Thanks
Dave

 

[Burnerman]

Hang on - when you say the boiler needs resetting, whats actually happening? Is the lock out lamp igniting on the control box, or is it the overheat reset that you press? Bit confused here!
John

 

[grrrrrowler]

Hi John
It's the reset lamp on the riello rdb that comes on and needs resetting - apologies for not being clearer.

Many Thanks
Dave

 

[Burnerman]

Its a fairly bizarre situation, this because although you have the room stat on high, the burner must still be cutting in and out, and so is therefore behaving as it should.....!
If it is the first start of the day thats the real problem, I would suspect that the boiler internals need a good clean out - indicating that the initial fresh air purge isn't doing its job - but once the flue is warm this should be less of an issue.
Is it possible for you to check the fuel pump oil pressure? I would suspect this first, then the photocell maybe. Once the burner is running, does it just purr away, no chuffing or visible smoke from the flue?
John

 

[grrrrrowler]

Hi John
Thanks for your reply.
The burner does cut in and out as it should - however if we set the thermostat to more than 22 degrees it cuts out after a while and the burner needs resetting twice to get it going again, until it cuts out a couple of hours later.
There is no smoke (apart from the white smoke/condensation coming out the top of the flue on the roof) or untoward noises or smoke.
When it's working it seems to be fine.
Just seems odd that the problem only occurs above 22 degrees.
Probably worth getting it cleaned out as it was last serviced about 18 months ago.
Regards
Dave
Edit: The problem only seems to occur during the day as well - ie it never occurs first thing in the morning when starting from 'cold' if that makes sense?

 

[Burnerman]

Normally if there is a flue problem, the first start of the day is the awkward one - yours gets going no problem?
A burner lockout is due to a flame not being detected by the photocell - therefore, flame out could be a solenoid coil on the oil pump (they fail when hot, usually) or a faulty nozzle spraying the fuel away from the electrodes and any resulting flame not being seen by the photocell (this would often produce smoke) or a photocell problem itself.
The pump pressure sounds ok but of course it may not be - its difficult to tell.
Anyway, some tests if you have a multimeter......the photocell should have a very high resistance in total darkness, but a much, much lower one in daylight. Next, check the resistance across the wires of the solenoid coil, when the thing is cold, and you know it will start. Then check again, immediately it locks out, and see what the readings are then.
As you can see, without basic tests on the fuel pressure, it gets a bit difficult for us!
John

 

[oilhead]

If it cuts in & out at low room temps, then it probably isn't running long enough for the solenoid coil to get hot and fail.(maybe) At higher temps, it would run for longer.

 

[Burnerman]

If it cuts in & out at low room temps, then it probably isn't running long enough for the solenoid coil to get hot and fail.(maybe) At higher temps, it would run for longer.

Aye, who knows. I'd be tempted just to bung a new one on anyway.
John

 

[grrrrrowler]

Thanks for your replies.

There is definitely no smoke.

And by cutting in and out I meant that the thermostat seems to do it's job, and that the burner only cuts out after it has been on for a while (ie isnt cold).

It definitely starts up ok in the morning.

It sounds like it may be the solenoid coil I guess - I will try to get hold of a multi meter.

Are the solenoid coils easy to fit or should I get an engineer in? I see they are relatively cheap to buy (£8 or so?).

Thanks

Dave

 

[Burnerman]

Yes, they are easy enough to fit - one knurled nut over the coil on the pump, and 2 wires going into the control box - via a plug I think. Check all of the connections for tightness when you're in there!
John

 

[grrrrrowler]

Thanks John
Is it one of these that I need then - the Solenoid itself or the coil?

http://www.oilburnerspares.com/spares/5550/oilburners/rdb-__-riello-oil-pump-coil.html

Many Thanks
Dave