Raypak RP2100 Intermittent Issue

kchinger

Well-known member
Aug 20, 2017
220
Southeast PA
Hello,

My heater is hit and miss this season. Beginning of the season was fine. Last few weeks, when I call for heat, it occasionally stops basically immediately and throws on the Service and Pressure/High Limit red lights. Never tries to light.

Cycling just the power to the heater doesn't seem to help. Turning off the pump and heater for like 30 seconds, then turning the pump on for a few seconds, then turning the heater on, then calling for heat, seems to somewhat reliably get it to light. Once it decides it's going to light it works fine, lights immediately, stays lit.

Control board was replaced 3 years ago.

I'm leaning towards a sticking pressure switch or something? What should I be looking for and testing to find something to replace?

I'm worried that one day my trick will stop working completely.
 

kchinger

Well-known member
Aug 20, 2017
220
Southeast PA
Of course after I say it's usually fine once lit, I went to check the temperature and it had kicked off with the same lights. I got it restarted, as it was restarting it kept kicking on and off really quickly, and once I even saw a bunch of orange go under the burners, looked like a backfire (I took the side cover off so I could check things).

Video is here.
All burners look good, it is glowing a bit towards the pilot maybe? I'm just glad it didn't backfire while I took the video (this was a few minutes later and it wasn't stopping and starting anymore).
 

swamprat69

Well-known member
Mar 30, 2019
590
Las Vegas, NV
Somewhat difficult to assess with so much camera movement. How old is the heater? Is the heater millivolt, atmospheric or LO NOx? Somewhat concerned about oxidation of gas valve, gas manifold and partial oxidation of burners. Has the heater had any regular cleaning or service other than repair service for a problem? Burner flame does not look greatly concerning and yellow/orange tipping may be due to entrained debris in combustion air, but again it is difficult to assess burner flame without a stable viewpoint, possible slightly inadequate combustion air. Again, somewhat concerning that oxidation on burners is on the underside of the burners ( might be an indication of restricted flow through the heat exchanger as would the oxidation of the gas manifold and gas valve, depending on age of the heater).
 

kchinger

Well-known member
Aug 20, 2017
220
Southeast PA
Somewhat difficult to assess with so much camera movement. How old is the heater? Is the heater millivolt, atmospheric or LO NOx? Somewhat concerned about oxidation of gas valve, gas manifold and partial oxidation of burners. Has the heater had any regular cleaning or service other than repair service for a problem? Burner flame does not look greatly concerning and yellow/orange tipping may be due to entrained debris in combustion air, but again it is difficult to assess burner flame without a stable viewpoint, possible slightly inadequate combustion air. Again, somewhat concerning that oxidation on burners is on the underside of the burners ( might be an indication of restricted flow through the heat exchanger as would the oxidation of the gas manifold and gas valve, depending on age of the heater).

Installed in 87 according to some writing on it. It's inside the pool house, so not exposed, but the muriatic acid is stored in there (other side, but still only a few feet, I wish I had a better place for it). I can try to get a steadier view if that helps, I was trying to check all the burners without setting myself (or my phone) on fire.

Took a couple pictures of what I guess is the nameplate. Sorry they're terrible, hard to get a good angle and lighting. Looks like maybe it's a model B-R-335-EN, but I can't find much info about what type that is.

We only bought the house 4 years ago, it was inspected by a pool company when we bought, but I don't remember how in depth they were on the equipment. I haven't done anything with it since except for drain and blow it out for the winter. Is there some maintenance I should be doing?
 

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swamprat69

Well-known member
Mar 30, 2019
590
Las Vegas, NV
From the serial no. date code it looks like the heater is from Oct. 1996 (~ 25 years old). Since it is listed as 120/240 Volts, it is not a millivolt heater. It is entirely possible that you are experiencing multiple problems. Best solution would be a cleaning/service by a qualified technician, but at 25 years old I would be hesitant about making any major repairs or parts replacements
 

swamprat69

Well-known member
Mar 30, 2019
590
Las Vegas, NV
This list Raypak – Model Number History seems to show the "R335" production dates as 1993-1999 and lists it as "obsolete". This parts list https://s3.amazonaws.com/AWSProd/sites/raypakcom/documents/archives/9100.553.pdf seems to show that it is either millivolt or atmospheric intermiitent pilot. "Service" may relate to pilot sensing and/or pilot gas/air mixture flow problem, heat exchanger restriction or burner gas/air mixture flow problem. "Pressure/High Limit" may relate to restricted filter, AGS/High Limit sensor failure, problem with either governor or bypass or possible scaling of heat exchanger. There does not appear to be an actual "pressure switch" listed in the parts list. As stated before, you may have multiple problems ranging from somewhat difficult to even more difficult. With your heater listed as obsolete and parts availability questionable ( I haven't checked on this myself ) you might consider replacement on a 25 year old heater. From what I understand you can still get an atmospheric heater without a combustion air/inducer blower (simpler heater with fewer parts to replace) if you are willing to sacrifice some heater efficiency. I am not against any DIY as long as you are both 100% comfortable/safe doing so. This might involve removing and cleaning pilot assembly, burners and gas manifold orifices, inspection of heat exchanger (combustion side) both above and below combustion chamber. Removal and inspection of water header, related safeties/controls and inspection of water side of the heat exchanger for scaling (not advisable if new gaskets are not available). Might be a "can of worms" and possibly fultile in the end for a heater that has a limited life expectancy even if repair is successful.
 

kchinger

Well-known member
Aug 20, 2017
220
Southeast PA
Pressure switch does look like it exists, 062237B, looks like it's available, although not cheap ($50+). When it's not turning on I might try bypassing the switch and see if it starts, in which case that switch might be bad. The way it sort of stutters makes me think it's some sort of switch. Either the switch is bad, or it's right on the edge of the switch on/off pressure so it's chattering, in which case there actually is low pressure (not high, right?), and I have no idea how to fix that, other than pulling the whole thing apart and cleaning it like you said, which sounds awful and unlikely to be worth it. I guess I'll try that, and then look into a new one if I have to (we're already spending $20k on doing new plaster/tile/coping, why not throw in a new heater too).
 

swamprat69

Well-known member
Mar 30, 2019
590
Las Vegas, NV
Sorry that I missed the pressure switch with only the faint tracing on the parts explosion diagram and no wiring diagram that I could find to decipher the sequence of operation. If you are thinking that it might be related to the pressure switch, I am sure that you have already assured yourself that the filter is clean and your filter pressure is in the normal range.
 

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kchinger

Well-known member
Aug 20, 2017
220
Southeast PA
So I checked the pressure switch, jumped the contacts together and it immediately started up. Ordered a new switch, less than $50, give it a shot. It also started leaking a bit once I bumped it around messing with the contacts, which probably isn't a great sign that it's in good shape.
 
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