Raypak RP2100 heater goes to CFH, SPK for a long time, then ":LO" or "ILO"


New member
Sep 13, 2020
Sedona, AZ
Hi all, used my propane Raypak pool heater for the first time in a long time yesterday. The pool was cold and we had a guest coming so I fired it up to warm up the pool a bit. Turned it off later when it was warm enough. Tried to do the same thing this AM, pool temp read 82 like yesterday and I turned it on at the 92 setting. Saw CFH, SPK but instead of the usual click whoosh of the burner starting and resulting heat felt at the top of the heater, nothing. Tried to turn it off and wait a bit, cycled power (when in off setting) but no change. I had replaced the display panel in 2013 and no problems since, until today. Any ideas? I can't seem to hear anything. Pool filter was running water through the heater.
Update: waited a while on SPK and eventially "ILO" or ":LO" displayed on the panel. ??


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Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40

The Error Code ILO is Ignition Lockout.
1. The heater has performed too many attempts to ignite the main burner and will take a short break.
2. Inspect pilot assembly.
3. If pilot assembly is OK, then the culprit may be your PC board.

Welcome to the forum.


New member
Sep 13, 2020
Sedona, AZ
Do you smell gas at all?

Do you hear any spark at all?

Check the gas valve to make sure that it is ON.

Check all gas valves to make sure that they are on.

No smell of gas, no sound of spark. Gas valve is on. I used it the day before and it started normally, although it was the first time I used in in almost a year. I'll see if I can safely figure out how to inspect the pilot.


TFP Expert
Mar 2, 2011
Go through the troubleshooting in the manual.

Are you sure that the tank gauge is good?

If you tap on the tank, does it sound full or empty?
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