truthsmiles
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Re: Furnace gas valve
Bob E. wrote: Thanks guys! These photos and information have been very helpful. I ordered the newer gas valve (#31098) because it looks like it has the gas inlet and outlet ports in the correct place (or at least close to it). Supposed to be delivered Thursday. I'll let you know if it works when I get a chance to mess with it...hopefully this weekend. If not, I may have to go with the 31150 and try to find that L-shaped tube on the outlet side. Otherwise, I don't think I will have enough room at the bottom of the valve to connect the gas line on the inlet side. Hey guys just wanted to drop in here and thank everyone for this thread. I have the hydroflame 8531-iii and encountered the exact same problem of not being able to find the Atwood 31155 gas valve because, well, they just don't make them anymore. So, even though I didn't know the results for Bob, I took the plunge and ordered the Dometic 31908 from Amazon as suggested, and it worked! BUT... it's never that easy, right? It took several hours of trying different things and head scratching, but eventually I got it to work by installing it sideways with the input port pointing UP (solenoids on the left, touching the fan housing), and drilling a hole in the top sheet metal to bring in the gas line from above. Additionally, I had to move not just the orifice over from the old valve, but the orifice AND the carrier "tube". Mercifully, the threaded outlet port on the 31908 is 3/8" npt thread, just the same as the 31155, so no adapter required. I had to do this to provide enough clearance to plug the ignitor wire in. Now, if drilling a new hole is absolutely out of the question for you, I think it WOULD be possible to very creatively use brass elbows and pipe nipples to get the input where you can use the existing side entrance setup. My GUESS is you'd probably want a 3/8" female flare to 1/4" female npt elbow, a couple of 1/4" street elbows, a 2" nipple (or maybe 1.5"?), and finally a female 1/4" npt to 3/8" male flare elbow. Alternatively, you might also be able to use a 3/8" flare street (swivel) elbow and a short piece of rubber/flexible propane hose - although with the exhaust pipe running through the same space I wouldn't take that kind of risk. Note that the inlet in this configuration is maybe an inch from the top sheet metal, so if you put an elbow on it will be touching the "ceiling" - not much room! For me, just cutting the hole in the ceiling made the most sense. It was the least expensive option and I just sort of stuffed some fiberglass insulation around the copper line once the flare nut was poked through. The furnace is very old and I just need it to work. The RV is also old and doesn't move (much), so I'm not worried about rubbing. You might decide to install some sort of grommet if you're going to be moving. Finally I might also note that there is a stamped bracket on the original valve that helps attach it to the fan housing, giving the whole works a little more rigidity. My furnace no longer has that feature due to the completely different valve and configuration. Anyway, thanks again, especially to BFL13 who made the suggestion. I have heat now, which is what matters! EDIT: Here's what it looks like installed...1.8KViews0likes1CommentRe: Suburban SW10PE - pilot works, but main burner won't light
UPDATE: Just wanted to circle back here for anyone else happening upon this post. Counter to the advice I was given, I ended up taking the gas valve apart, applying my best troubleshooting skills, and then when I didn't find anything obvious, re-assembling it. I installed it back on the RV and shortly after I lit the pilot light flames sprang forth from all around the valve! Fortunately I was watching and forcefully blew on the flames, which put them out for a second and I was able to shut off the valve. So, obviously I didn't put it back together correctly :-/ So, lesson learned, and @Old-Biscuit was 100% right. I shouldn't have messed with the gas valve and just replaced it - which I did, and it worked perfectly :-) PS - As it turns out the reason the old valve wasn't working was that it was filling with water. The plastic cover on the temperature probe had been compromised by the threads on the tank and water was leaking in. Photo attached.1KViews0likes0CommentsRe: Suburban SW10PE - pilot works, but main burner won't light
Old-Biscuit wrote: Gas valves are NOT SERVICEABLE Thermistor??? That is a temp sensor for a fridge What are you referring? Thermocouple? (Pilot flame is staying ON so thermocouple IS working---it generates millivolts that HOLD magnet open allowing gas flow. When you push down on knob you are bypassing that to get gas flow....then thermocouple takes over) And that probe out the backside... That is the ECO (Energy Cut Off....a high temp probe. BLOWS if water temp gets to 190*F to shut down ALL gas flow--no pilot/no main. Gas Valve has to be replaced if it blows) Thanks for the additional reply! No, I'm not referring to the thermocouple - the pilot light stays lit so clearly that part of the gas valve is working (there is voltage from the thermocouple, and that voltage is holding the solenoid open). And, yes I agree the ECO inside the probe is intact or there would be no gas flow at all (even to the pilot). What I was referring to was the 'main' side of the valve... obviously the gas valve must sense the temperature of the water somehow (via the probe, I assume), and that in turn controls whether the main valve is open. As far as I know, the thermostat must be purely mechanical (bi-metallic?), or it's electrical and there's a thermistor that allows/disallows current to flow through a second solenoid to open the main valve. By your reaction it sounds like it's the former - so thanks! I do understand that the standard answer is to say "It's not serviceable - you have to replace it!", but I was hoping a DIYer who has opened one up and fixed it might be able to tell me whether it's even worth trying. In any case, I've got some torx security screws on order and plan to crack it open. I'll report back if I'm able to figure it out and fix it! :-) Kind regards.1KViews0likes0CommentsRe: Suburban SW10PE - pilot works, but main burner won't light
Old-Biscuit wrote: Gas tube/orifice blocked....remove/soak in alcohol--blow with LOW pressure air (High Pressure Air or poking things thru orifice will cause damage---it is a metered hole) Gas control defective---replace gas valve Thanks for the reply! I've already removed and inspected the gas tube and orifice - both were clear, I could easily see through and easily pass 'breath' through. There were cobwebs in the burner tube, but gas wasn't even making it out of the orifice. Is there any hope for servicing the gas valve? I'm still suspecting the thermistor. I know it's not 'normal' to replace it, but I'm down to give it a shot if it'll save me $150. :-)1KViews0likes0CommentsRe: Suburban SW10PE - pilot works, but main burner won't light
Thanks for the response! I just tried moving the temp adjustment and it SEEMS to move the shaft, but as you can see in the picture it's completely covered by the plastic cap - so I can't tell if it's actually moving. That being said, it feels exactly how I would expect it to feel: smooth, light resistance. It doesn't 'catch' or 'slip' or feel loose at all. In any case, it's currently below 30°F outside right now so I'd expect it to come on no matter where it's set(?)1KViews0likes0CommentsSuburban SW10PE - pilot works, but main burner won't light
Hi all - first time poster. Just bought a very neglected RV (brand unknown - even DMV couldn't figure it out from the VIN - but that's a question for another day!) As the title implies, my RV has the SW10PE water heater - it's the kind with a manual pilot light (no electric ignitor) and a separate AC electric element. The gas valve is a SIT-610-AC3. Here are some images stolen from amazon - pictured is exactly what I have... Front: Back (you can see the thermostat probe here): The symptoms are that I'm able to light the pilot and turn the valve to "ON", and the pilot stays lit. So, I know the thermocouple is working and the gas valve is at least partially functional. However, no matter where I set the temperature the main jet doesn't light. I've yet to disassemble and clean it (I know spiders like those tiny holes), but the soap bubble test shows nothing at all coming out. So, at this point I suspect it may be the thermostat that's faulty. To be sure, the condition of the tank may be REALLY bad. The sacrificial anode is completely gone and the electric element is open, so it wouldn't shock me if the gas valve thermostat is corroded/shot. Related, I found ***Link Removed*** where the user describes a gas valve that won't shut off (overheats the tank) and the consensus seemed to be a faulty thermostat. Mine is the opposite problem, of course, but before I go making assumptions I thought I'd ask the experts here! So, here are my questions: 1) Is there a test I can perform to confirm a faulty thermostat? Is there an ohm specification? Or should it just be 'closed' (0 ohms) when heat is needed? Is there any other recommended testing procedure? 2) If I can confirm the thermostat is faulty, does anyone have a link to a replacement part? I'd hate to replace the entire gas valve if that's the only problem. Thanks!4.1KViews0likes7Comments
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