Oil burner photo cell

SSE · Jan 11, 2014

Hi folks, pick your brains a wee bit here. Was looking at a converted Rayburn for someone today, the thing keeps locking out every so often. It's run of a programmer to a Danfoss controller onto the burner & oil pump etc. After a bit of investigating someone told me there's a good chance it could be the photocell needs wiped or replaced. After locating it & giving it a wipe I tried again & nothing, was locking out again. I held the button on the controller as this gives you a signal using the lights to describe the fault, the light flashed three times which I was informed means it's a photocell fault. Now I'm waiting on a photocell to come home I ordered but tonight whenever the there is power coming from the programmer to the controller everything is fine until you press the controller start, it's tripping the RCD. Is there anything else I should be looking at or do you think the photocell is causing this now? Apparently it's been cutting out for the last 2 weeks every 3-4 hours but tonight is the first it's tripped the RCD. To be honest the burner etc is over 10 years old so it could be on it's way out! I've never worked internally on one of these things before, just having a look as a favour but I'm keen to know a bit more & maybe pick up some info for this one obviously & for future incase I come across this again. Any help would be much appreciated.

UNG · Jan 11, 2014

Check the coil on the oil solenoid valve, A mate of mine had a similar fault on his oil fired Stanley range that numerous burner engineers had looked at over 18 months or so I was staying over when it started playing up for the final time and the burner would not stay on and sometimes would not fire at all swapped the solenoid valve coil over from the cooker burner onto the heating burner and got it working. Did an IR test on the suspect / faulty coil and was getting a very low reading to earth replaced the coil and the problem was solved

Just looking at the info in your post is the burner actually firing and then locks out because the photocell is not detecting the flame or is the burner not firing at all and the photocell because it is not seeing a flame then locks the burner out

Guest111 · Jan 11, 2014

As above,check the solenoid,I went out to one and the guy had replaced every part on the burner except the solenoid and it was actually that which had gone.

UNG · Jan 11, 2014

phil d said:
As above,check the solenoid,I went out to one and the guy had replaced every part on the burner except the solenoid and it was actually that which had gone.

Sounds like it might be the same guy or one that went to the same training school that went to my mate's house changed more or less everything except the solenoid and that was the faulty part

phazed out · Jan 11, 2014

In the factory where I once worked there where oil fired space heaters which I think were called Dravoes.

To test the photocell a DC µA meter was connected in series with the photocell and the control unit.

If my memory serve me right a small DC current will flow when the flame is sensed.

The value of this reading is set by the type of control box, I think the readings were:

No Flame/Dark ≤5µA
Flame/Light ≥65µA.

Hope this helps.