Heater ignition lockout

mongoctMay 18, 2011

I have a Raypak r2100 ASME 400k heater. About 2 years old.

The heater ran fine a few weeks ago through several cycles after I opened the pool. It ran a couple of times for about 10 minutes, once for about two hours. But now I get ILO, or ignition lockout, when I try to fire it up.

First, my understanding of "ignition lockout" is simply that the heater is trying to fire, but it doesn't, so the ignition shuts off after a predetermined time. Correct? Incorrect?

I have a 375 gallon tank, at about 70%. The primary tank valve is fully open. I see no kinks or damage to the lines. I've tried closing the valve a bit, etc, no effect.

Tank to heater distance is about 15 feet. The secondary ON/OFF valve just prior to the heater is fully open. I've cycled that several times.

Fireman's switch has continuity. Pressure switch is fine. None of the safeties seem to be causing interference.

There is a black pipe union between the secondary ON/OFF valve and the heater's built-in ON/OFF gas valve. The heater's valve is ON, I've cycled that several times. I've cracked the union and the gas flow is significant. Propane flow or volume does not seem to be a problem.

When I first got the ILO I ran it through several ignition cycles, turning the heater power on/off. No luck. I then cracked (opened) the union to sort of purge the system and check the propane flow. The gas flow was significant and the heater immediately fired up right afterwards on the first try. I thought all was well. Then the next day I tried again and all I got was "ILO", and since then cracking the union has no effect.

With everything set and the heater turned on, there is a "call for heat". I can feel and hear a single "click" in the heater's gas valve which I assume is the valve moving to the open position.

I hear the rapid "click click" of the ignition firing. The small pilot flame near the burner assembly lights off, so some gas is getting there. The "click click" of the ignitor continues. But there is no odor of uncombusted propane, and the main burner assembly does not light off.

So it seems that propane is getting to the pilot through the small 1/4" tube and is being properly lit off. But even though the main valve "clicks" it doesn't appear that the valve is allowing propane to the main burner assembly.

Any ideas on additional troubleshooting or possible repairs? The local gas guys are about 40 minutes away and are not interested in making a house call.

Would this warrant removing the heater's gas valve, removing the burner tray assembly, checking things out, and re-assembling?

Any help would be appreciated. I can take and post photos if needed. Thanks in advance.

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


    Bookmark   May 18, 2011 at 6:55PM
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Rack Etear

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.


    Bookmark   May 19, 2011 at 12:04AM
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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.

    Bookmark   May 19, 2011 at 12:52AM
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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:

� 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.


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.

    Bookmark   May 19, 2011 at 3:00PM
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Rack Etear

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.

    Bookmark   May 19, 2011 at 11:33PM
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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.

    Bookmark   May 19, 2011 at 11:47PM
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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!


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

    Bookmark   May 21, 2011 at 2:16PM
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