I have a Raypak 2100 pool heater (C-R206A) with the digital ignitor. Over the weekend, I got the RLS (rollout switch) error. I bypassed that switch to see what the flames looked like, and sure enough, they rolled out the front, right by the rollout switch. The flames inside the burner chamber were yellow, not blue. I have another Raypak 2100 on my hot tub (about 100' farther from the house), so I was able to see/hear the correct ignition sequence and what the flames should look like.
I dismantled the upper half of the heater and power washed the soot from the heat exchanger. There was a good bit of soot in there - significant airflow restriction, I'm sure. I replaced the bypass valve (definitely shot), and the unitherm governor (maybe ok - opened a little in hot water - but I replaced it anyway). I put everything back together this afternoon. I had no leaks (yay), but also no fire (boo).
When I try to fire it up, I hear the gas valve click open, and it tries to spark (SPK on display, and I hear the zapping sound). However, the pilot never lights up. I let it try to spark for about 30 min, to no avail. I do not smell gas anywhere around the heater. It seems that I'm not getting gas to the pilot (blocked pilot orifice?). However, when I did have fire last weekend, those flames didn't look right compared to the heater on my hot tub. Does that mean the gas wasn't getting to the burner tray, either? Or is the sooty heat exchanger enough to make the flames yellow instead of blue?
With the hot tub doing fine another 100' farther away, I don't suspect gas pressure (both have 3/4" iron pipe for the gas lines). Check that pilot orifice first? What else should I look for or try?
I appreciate any thoughts or suggestions.