Riello RDB 2.2 locking out

[nevermore]

I'm helping a friend troubleshoot a Riello RDB 2.2 burner installed in an old Firebird boiler.

The burner locks out after roughly 15 seconds. The fan is working.

So far I have:

1. Swapped the photocell and verified both new and old working using a multimeter.

2. Swapped the solenoid coil and verified both new and old working.

3. Tested fan motor voltage.

This shows 53/54V for the first ten seconds or so. Then there is an audible click and the voltage goes down to 42V. However using another multimeter the reading is over 1000V. Then the burner locks out.

Does this point to the motor fault or should I consider a short somewhere further down the line (ignition wires or electrode?).

As far as I know the boiler has not been serviced by the previous owner, and seems to be in less than perfect condition. We have been also unable to find an engineer willing to take the job in North Wales.

I'll be thankful for any ideas.

 

[Johntheo5]

You could wipe down the electrodes and check the gap although I have never had to adjust mine (Riello G5X) in 18 years, the settings are below but probably similar for your friends burner. Also access the electrodes insulators as far back as possible and wipe these down as well. Presume you have checked tank oil level OK and fire valve open etc.

 

[oilhead]

I would start at the tank and ensure any filters are clean and you have oil at the pump inlet. If the nozzle is wet after lock out, you still do not know whether the pressure is sufficient. You can get a good idea if you don't have a pressure gauge by letting the pump discharge into a container through the pressure port. Have you checked the nozzle? Have you checked for a spark? You should be able to hear the spark as the solenoid clicks open.