Oil Boiler Oddity

[Mark Nicholls]

Our oil boiler goes into a mode where it is constantly trying to ignite. I.e. it tries to ignite, then 2 seconds later tries to ignite etc. If I take out the nozzle and clean it up it will work for another 2 months before it does the same thing again. The filter is clean as a whistle and I don't think it is the supply as it does not lock out.

Any ideas why it is doing this?

Boiler is a Camray Quartet Model 110-150 Burner is a Riello 40 Nozzle is Delavan 60w t02 1.25

Thanks Mark

[Michael Chare]

Items to check::

a) Photo Cell - is it dirty?

b) Are ALL filters clear? If you have a paper filter element maybe in fuel tank filter this will eventually clog. It needs to be replaced.

c) Can you see flame? If so is it going out and then immediately being relit? In that case slightly increasing the oil pump pressure may solve the problem But in theory you now have to retune the boiler by adjusting the air supply.

I now change my nozzle every year or so. Some boiler manufacturers (and Danfoss) recommend this.

Michael Chare

[John]

A few things "could" be pertinent:-

1. Flame failure should result in the burner control going to lockout but it is possible that subject to type of control and length of time flame is present the control box is being satisfied that the ignition was successful and is treating the flame going out to a relight attempt. I would be inclined to make absolutely sure that removing the photocell and covering it from exposure to light does result in a proper lockout by the sequence control box. Which model of burner is fitted to your boiler? Also which type of sequence control and type of photocell are fitted?

1. Please confirm you are burning kerosine and the fuel tank is not contaminated by water etc.

2. Subject to burner/oil pump in use is there a secondary oil filter within the pump, or a screw down firestop valve (non approved pattern now) which has vibrated nearly closed, or a kink in the fuel pipe, or water in a low point in the fuel pipe run which is freezing and forming an ice plug thus stopping (temporarily) the flow of fuel.

1. How old is the nozzle - are you simply cleaning it or fitting a new one?

2. If you have a multimeter try measuring the resistance of the photocell both with it covered from light and with it illuminated

1. Again subject to model of burner you could try running the burner up through its ignition sequence and illuminating the photocell with a torch within a second or so of the flame actually igniting to see if you have a control box sensitivity problem.

2. I would counsel against altering the pump pressure unless you have a pressure gauge fitted to the test point and a combustion analysis set to hand. Any upset of the pressure/air/fuel adjustments can and often does lead to sooting/fuming.