HELP I think I have an electrical issue??

First, ensure the pilot assembly and ignition module are grounded. The pilot can be grounded by using a double insulated or bare, solid copper wire from a mounting screw directly to the "GND" terminal on the module, if so equipped, otherwise to chasis. You can also ground the neutral side of the 24V transformer.

If that doesn't work, consider an isolation transformer.

Up here, we don't require the gas line to be bonded unless it's underground. In the States, NEC (250) and Fuel Gas regs are a little confusing and ridiculous, but it certainly doesn't hurt to do so. The gas line can't be used AS the ground. Neither should the water line.

"Joe the boiler guy" probably knows more about the control wiring than an electrician. Can't be wired backwards, depends on a rectified signal to prove pilot.

Jea48: It's more likely that the thousands of volts in the spark are polluting the AC, dedicated line or not, than creating RFI.

Any solution yet?

Doesn't surprize me that the furnace installer didn't come out for free. The suggestions I made in my first post can be above and beyond the manufacturer and code requirements. The installer probably did it right, but it might be better.

Be specific:
1) Make sure furnace chasis is properly bonded
2) Add heat resistant ground wire from pilot assembly (not typical) The screws that hold on the pilot are very short and a wire connector will be required.
3) Ensure ignition module is bonded (normal)
4) Bond neutral side control transformer (as opposed to floated)

There are filters that can be hard wired into the furnace but you would only require to filter the control circuit/transformer which would be no more than 40VA and not the blower/combustion fans. There are many hard wired line filters/spark quenchers that are available.

I'm not dismissing RFI but suggesting tackling the simplest solution first.

See if you can order a Okaya XEB1202. Just google it. Should only cost a few bucks. On AC circuits, it's wired parallel to the load. Probably better on the 24V side. Notice polarity.

http://www.okaya.com/images/noise/1200.pdf

I take that back about putting the XEB on the 24V side. The little control trannie might not be very tolerant of parallel loads. Simplist way is right at the marretttes (wire nuts) of the incoming power. WTH, get a few and have a blast... parallel, reverse parallel...

I wasn't serious about Tim digging into this himself. We know the tech won't have any kind of line filter in his truck and it's not likely stocked at the local distributor's either and might have no idea where to look. Unusual stuff, espescially for residential. Tim is more likely to get a shrug and "call somebody else" than a solution, if it does get complex.

I'm pathologically not serious. I'm not being serious right now, seriously.

No, thank you. Was having a problem with 2 boilers chewing up pilot valves mysteriously and it was my research into your problem that led to the Okaya snubbers. Won't be sure if it worked until the valves last for a couple years.