Can't fire up boiler

Anthony.C

Member
May 17, 2024
20
England
Hi, I can't seem to fire up this boiler. Would it be obvious if it ignited and should there be a smell of gas when trying, because there doesn't seem to be?

The "gas controller" switch is adjusted with a screwdriver, should that be turned fully clockwise to be on?
Also, the boiler is non-electric but it is wired to a timer which isn't working, not sure if that would affect it.
 

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This might be close to the manual for your heater https://www.parts4heating.com/v/vspfiles/images/pdfs/ESGSeries2.pdf It is a millivolt heater. Is the pilot lit? You seem to have excessive corrosion by the gas valve, gas manifold and electrical connections. Are you by the ocean? What part are you calling the " gas controller switch" ? Any corrosion at wiring/terminal connections will reduce the already very small voltage (millivolts) available to operate the heater.
 
Hi and thanks for replying. I did find that manual, it is very similar but the start up method is slightly different.
I was referring to the screw next to the TH in the pictures as the "gas control" but I now realise that the diagram in "Figure 1" is referring to the whole section as the gas control so I don't know what that screw is for, it only goes half a turn each way. I am fairly certain the pilot isn't lit, is it possible for it to be lit without knowing, I've never tried to light it before?
I have tried spraying the connections with an electrical contact cleaner in case it helped but we couldn't be much closer to the ocean!
Is there anything else I could try?
 
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I am not familiar with the gas valve that is used in the heater, but this seems to be it 100441 VS8820A Honeywell Gas Valve 3/4"NPT Gn 0.75V - Valve Do you have the original manual for your heater? The 2 yellow wires at the gas valve are for an auxiliary safety for the powerpile (millivolt generator)/ pilot which is mounted above and to the right of the gas valve. This safety interupts the voltage of the powerpile to the gas valve that shows the valve that the pilot is lit. You should show continuity ( 0 ohms) across these 2 wires. The red button next to the safety is a piezo spark generator for lighting your pilot when pushed in. Like I said, I have never seen this gas valve before and am not sure of the lighting sequence for the pilot. If you have the original manual, you would follow the pilot lighting sequence for the pilot listed in the manual. It is possible that the powerpile if it hasn't been replaced in a while can no longer generate sufficient millivolts and may need to be replaced. Also the heater should be cleaned and checked by a qualified technician on a regular basis
 
Thanks for that. I don't have the manual but the lighting sequence is printed on the service door, as can be seen in my final picture. I think I will have to find a qualified technician.
You need to check the output of the pilot generator. It should in the 600-650mV range. Anything less than 500 and the heater won't light if everything else is good.
Your main valve is so corroded that it should be replaced as, even with the correct operating voltage, it may not open.
 
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