Raypak RP2100 pilot lit but burner won't fire

[jdjanka]

Hi all,

We have a Raypak RP2100 natural gas heater for our in ground pool/spa combo. When we moved into the house a couple months ago I couldn't get the pilot fired so we called up the home warranty place (included when we bought the place) and they sent someone out for a quick $60 deductible and it ended up being some carbon buildup in the pilot assembly. They purged the line, cleaned the holes, and got it lit within a few minutes. The pilot has stayed lit and we've used it 5 or 6 times since. Fire it up via the switch and crank the thermostat to hi and it works great.

About 2 weeks ago the burner failed to light when I turned on the switch, regardless of the thermostat position. The pilot is still lit but I don't hear any difference in the gas flow when turning on the switch so I'm assuming one of the safety circuits on the regulator is preventing it from opening up fully to supply the larger volume of gas for the burner to fire.

I'm pretty handy once I'm familiar with something but being that this is our first pool as well as our first gas appliance (ever) I'm a little unsure of how to properly troubleshoot the issue. I have no problem calling the home warranty co to come back out and look at it, but I'd rather figure out how to properly troubleshoot and resolve it myself if at all possible.

Thanks all!

Jason

 

[marty]

Is pilot a yellow lazy flame? try cleaning burners, maybe gas pressures to low.
I know sounds strange but sometimes if water level is low and/or really dirty filter, the digital safety thing-a-ma-bobs kick on, after you assess both issues try turning off on at breaker.

Im sure the pro's will chime in.

 

[ps0303]

If you have a pilot but it will not kick on then maybe there is another issue such as one of the safety's. Is the filter clean and you have good flow? If it's worked before I doubt gas pressure unless you have work done on it or you've added a bunch of other gas devices. Clean your filter and see what happens.

 

[jdjanka]

Thanks for the replies guys. I hadn't thought of the flow sensor and actually hadn't sprayed out my filter in about two weeks so I did that today. Still no luck unfortunately. The pilot is a strong blue flame and seems to look great, but not getting any action on the burner when flipping the switch on. BTW, it's a millivolt system, so no breaker.

Any suggestions on how to troubleshoot the safeties?

Thanks again to all

 

[Pool Clown]

Page 28 shows millivolt safety circuit. You will need to remove the wires from each switch(isolate), to test for continuity while the pump is on. Please note that you may loose pilot when doing this if you disconnect red or white wire from gas valve as the pilot generator supplies millivoltage to the pilot valve to keep it open. You should have contact on both hi limits/AGS, thermostat, Manual switch(outside of cabinet), pressure switch, and roll out. Of all those, roll out is most common. I would start there(red wires, front of cabinet), then pressure switch, therm, and so on. Open roll out suggests sooted exchanger, or down draft(wind) condition. So don't just replace roll out without investigation of why it opened. You may be able to hear the thermostat click as you are rotating the temp knob to verify it is closing, For this one you will have to turn off the pump so it is quiet to hear the click.

Good Luck.

http://globalimageserver.com/fetchDocum ... 29edd2f913

OR...

You may want to just call the guy back and have him come out and, fix it. Because, IMO, he really hasn't fixed it yet. And since he hasn't fixed it, i wouldn't pay another deductible either, IMO of course.

 

[Punudski]

Page 28 shows millivolt safety circuit. You will need to remove the wires from each switch(isolate), to test for continuity while the pump is on. Please note that you may loose pilot when doing this if you disconnect red or white wire from gas valve as the pilot generator supplies millivoltage to the pilot valve to keep it open. You should have contact on both hi limits/AGS, thermostat, Manual switch(outside of cabinet), pressure switch, and roll out. Of all those, roll out is most common. I would start there(red wires, front of cabinet), then pressure switch, therm, and so on. Open roll out suggests sooted exchanger, or down draft(wind) condition. So don't just replace roll out without investigation of why it opened. You may be able to hear the thermostat click as you are rotating the temp knob to verify it is closing, For this one you will have to turn off the pump so it is quiet to hear the click.

Good Luck.

http://globalimageserver.com/fetchDocum ... 29edd2f913

OR...

You may want to just call the guy back and have him come out and, fix it. Because, IMO, he really hasn't fixed it yet. And since he hasn't fixed it, i wouldn't pay another deductible either, IMO of course.

This was very helpful Pool Clown. However, I had the same issue as jdjanka and wanted to add a bit more info based on my 6-hour troubleshooting extravaganza today. I checked all circuits and they were functioning fine, but still no luck. My pilot was lit with a blue flame and appeared to be fine. I jumped the "TH" connection as well, which should open the gas valve according to the Raypak manual. Nothing. I then found this site for the type of Robert Shaw valve I have (http://www.robertshawtstats.com/spaw2/SiteContent/Files/faq/ControlTips-MillivoltSystems.pdf). It states the mV readings should be between 100-325 mV, which I was well below (mine was ~70 mV). I held a flame next to the thermopile while also recording the voltage, and the burner fired when it reached about 115 mV.

I re-cleaned the pilot valve and bent it a little closer to the thermopile. Now my readings with just the pilot light going are around 300 mV, which is high enough for the pilot to stay lit and generate enough mV to open the gas valve fully for the burners to fire.

I almost ordered a replacement gas valve after going through the troubleshooting session in the manual. Very glad I didn't. I found it interesting that nowhere in the Raypak manual does it state the required mV reading for your burner to fire. Just because the pilot is lit (and blue) doesn't mean the thermopile is hot enough to open the valve fully. I ended up taking apart pretty much the entire furnace, including taking apart and inspecting the gas valve. In the end, just a small tweak to the pilot/thermopile assembly was all it took. Now that I wrote this on the internet, I can read this post next year once the same problem happens again and I can't remember what the heck I did to fix it...