Check the gas orifices for webs. Reseting power to the heater for 30 seconds will clear the ILO.

Scott

If the pilot light, and continues to spark, the flame rectification system isn't working for some reason. The most common cause of this, is a clogged pilot orifice.

These can be cleaned out by removing the pilot, and removing the tube on the pilot side. There is a small metal piece with a really small hole in it. You clean the hole out with a small needle and re-assemble.

Here is a picture of what the pilot orifice should look like. Its inside the pilot you have to remove the compression fitting attached to the pilot line to see it.

http://www.etundra.com/LP_Gas_Pilot_Orifice-P28140.html?utm_source=google%2Bproduct&utm_medium=organic

Thanks guys, I appreciate you both taking the time to answer.

So even though the pilot lights but the burner doesn't, it's not the burner assembly orifice but instead the pilot orifice? I have the electronic ignition, similar to the one on the right.

That would be roughly 7P in the diagram?

Thanks so much.

{{!gwi}}

I removed the pilot assembly, the orifice looked clean. Still I cleaned it with a fine wire, blew it out, reassembled, and got the same result.

I then removed the entire burner assembly. While the individual burners looked fairly clean, I still took them all off the burner bracket. I ran a fine wire into each burner orifice. No obstructions.

I unthreaded the gas valve from the burner manifold. There was a little debris in the manifold; some metal filings and a few small (about 1/4" diameter) metal "slugs". The slugs appeared to be remnants from when the orifice holes were punched into the manifold.

Cleaned those out, then again ran a fine wire through the orifii (?) to make sure they were clear.

Used RectorSeal where needed and reassembled everything.

Same result as before; the pilot lights quickly, the pilot ignitor continues to "click", but the main burner does not light off, nor is there any odor of uncombusted propane.

There is a note in the troubleshooting guide:

MAIN BURNER LIGHTS? NO
� Check for 24 VAC across MV-MV/PV terminals. If no voltage, replace module.
� Check electrical connections between PC board and gas control. If okay, replace
gas valve or gas control operator, i.e. pilot gas valve, flow switch etc.

I did get 24V cross the MV-MV/PV terminals and cleaned the gas control terminals.

Blah!

I do have a question. With the pilot lighting off, it's obvious that some propane gas is getting through the heater's main gas valve. Are there two valves within the gas valve, one to feed propane through the small 1/4" tube to the pilot, and another to feed propane to the burner manifold and thus to the burner orifii and then to the burners?

Is there some sort of trigger where the small pilot lights off, then a signal gets sent to open the other valve to provide gas through the burner manifold?

Is that any way related to the ignitor still firing? ie, as long as the ignitor fires/clicks, the main valve won't open to allow propane into the burner manifold?

Thanks. Always looking to learn. Especially when the pros won't make house calls.

Typically, the heater will stop sparking, then send power to the main valve. There are 2 solenoid on the valve, one for pilot, one for the main burner.

I would first start by checking the green grounding connections on the heater. Tighten them if loose, and remove any corrosion.

Sometimes with these type of problems you have to throw parts at the heater. If I had to do this, I would start with a pilot. If that didnt fix it I would move to the control board.

Good luck.

That was the last thing I did this afternoon. Took it part again and used emery paper on any and all corrosion, even where there was none. There really wasn't much but I figured what the heck.

Appreciate your help. Thanks.

I read on another thread where someone had a similar problem and they discovered that their first main burner piece was slightly popped up and out of the holder slots in the burner tray. They reset the single wayward burner back in the slots and it solved their pilot rectification problem.

While my burners were securely seated, it gave me the idea of changing the relationship between the pilot light assembly and the burner assembly.

So I loosened the pilot bracket's securing/ground screw and slightly tweaked the pilot bracket, moving it about 1/8" to the left so the metal assembly surrounding the pilot ignitor was physically touching the metal of the first burner.

I turned on the heater...the ignitor fired...the pilot lit...and then the ignitor stopped firing...and the main burner lit off!

Halla-freaking-lulia.

I've run it through a couple of cycles and it continues to fire properly.

While I'm still unaware of specifically just how the pilot rectification process occurs...how the heater recognizes that the pilot is lit (electrical thermocouple, optical, wizardly magic?) and thus kills the ignitor and then actuates the solenoid for the main burner gas valve to open...it's working. I'll take my good luck and run with it. Or hot tub with it.

Thanks again to racket and poolguy for helping me out.

The good news? I can now tear down, clean, and rebuild this heater in about a half an hour. For better or worse. lol