Our front heater was getting a little cranky on the last trip. Took it apart today and found the "Burner" is rusted out - needs to be replaced. This is Hydro Flame part #32811, which is NLA (no longer available). There is no "official" substitute part available from Atwood, and as far as I can determine it is not being reproduced, even by the Chinese!
Anybody have any "secret" sources for these obsolete parts? There are probably boxes of them sitting on a shelf somewhere, but they don't show up in my online search. I would hate to have to replace a (otherwise) perfectly good furnace just because I can't find a $20 part. Photo of item below:
Maby one of these,
Part number 68567 here
http://ronsrvservice.com/wp-content/uploads/2012/06/18a_583-600D_Replacement_Parts.pdf (http://ronsrvservice.com/wp-content/uploads/2012/06/18a_583-600D_Replacement_Parts.pdf)
Burner 8500 (http://www.dan-marc.com/85-32811.html)
Hydro-Flame Burner Head: nwrvsupply.com (http://www.nwrvsupply.com/product/36043.html)
Read down at the bottom below the picture says not the exact but will work
Chuck, Instead of looking for just the burner do a search for a rebuild or repair kit, this kit contains both a burner and an igniter. Do a search here and you will find a prior post of mine that gives the numbers. I will search the forum later this afternoon if you can't find it.
Gary B
Howdy Gary and Chuck,
This may be Gary's post: Atwood Hydroflame Furnace UPDATE (http://www.foreforums.com/index.php?topic=17137.msg114115#msg114115)
Good Luck, Dave A
Thanks for all the helpful replies! This Forum is UNBEATABLE for stuff like this!
Stump: I sent a email to Ron's RV to inquire about their stock/ability to find a burner. I already had the nwrvsupply link marked, but was holding out for finding the correct part number. Thanks for the leads.
Gary: Thanks for the lead to the kit. I had seen reference to this kit, but passed over it because it did not directly match my furnace model in the "application" listing. Good to know it will work - I will add it to my "search parameters". Thanks for the info.
Dave: Thanks for finding Gary's old post - I was looking for it when your response popped up...I wasn't having any luck, so THANKS!
Google Atwood 38548 as per Gary's post, and there are plenty of those kits available 12.00 to 20.00
Update to close out this thread. Sorry, it's kinda long, so go get a cup of coffee...
I have got my furnace working again just like new, or perhaps better than new! For those who may want (or need) to attempt repair of a furnace, I offer the following helpful (I hope) info.
I now realize these Atwood (Hydro Flame) RV furnaces are pretty simple devices. My comments will apply specifically to the units installed in my coach, but I think they are all similar. You can access all the commonly replaced parts from the outside of your coach. It should not be necessary to remove the heater from the coach unless you are installing a complete new unit. I found a very good .pdf copy of a 2004 edition of the Atwood service manual here:
http://bryantrv.com/docs2/docs/hflamefurn04.pdf (http://bryantrv.com/docs2/docs/hflamefurn04.pdf)
This manual should cover the Atwood heaters installed in most 90's model Foretravel coaches. It contains a detailed parts listing for most models - very helpful. To determine the model number of the heater(s) in your coach, open the outside metal access cover, then drop down the inside hinged plastic cover. Model info and wiring diagram contained therein. With model number and above referenced manual, you can look up any required original part number.
So, finding the OEM part number is easy - finding the actual part may be more of a challenge, as detailed in my original post. In the case of my "burned out" burner, the OEM part is NLA (no longer available). With the help of forum members (see posts above), I identified 2 possible replacement part numbers: #38548 (kit with burner and ignitor), and #36043 (burner alone). I called several RV parts specialists, asking their advice. They unanimously steered me away from the kit, and recommended the replacement burner #36043 as a substitute for my original burner. This part application IS NOT sanctioned by Atwood - their only official solution for fixing my furnace would be "Buy a New Furnace" (for $600-800). No surprise there...
I ordered the burner from Amazon (Amazon.com: Atwood 36043 Burner: Automotive (http://www.amazon.com/dp/B004QMYYF0/ref=pe_385040_127541850_TE_item)). Comparing it to my old unit, it is basically the same in shape and size, but with some detail differences. The new one has a plate across the opening of the burner - the old one does not have this plate. The old one had a threaded mounting stud that is missing from the new one. Looking inside the burner, the old one has a welded in additional piece of metal (flame guide?) that is missing from the new one. In spite of these details, the new piece mounts correctly and seems to work just fine, so I am happy!
Having heard many good things about the Dinosaur line of replacement electronic boards, I decided to try one in my heater, The original problem I had with the heater was "intermittent operation". With the thermostat set to maintain a given temperature, the heater would come on one time (or several times) and work fine. The next time it came on, it might (randomly) run the fan but the burner would never light. Then the fan would continue running, blowing cold air, until I recycled the ON-OFF switch at the thermostat. One of the selling points of the Dinosaur board is it will try for a light 3 times, instead of just once like the OEM board. In case of a little air in the gas line, or very windy conditions, this would help assure that the furnace will operate when required. Another good point about the Dinosaur board: it has a built-in LED that glows "green" when power is directed to the board by the thermostat, and "Red" when the gas valve is opened. This can help verify correct wiring and operation.
The Dinosaur board was also ordered from Amazon (Amazon.com: Dinosaur Electronics (UIB S) Small Universal Ignitor Board: (http://www.amazon.com/dp/B0002MG2IK/ref=pe_385040_127541850_TE_item)). It is exactly the same size and shape as the OEM board, mounts in the same place, and the original wiring connector fits perfectly. When I first tried the heater after my repairs, it would not light due to air in the gas line. I could distinctly hear the board making 3 attempts to "light the fire". Once the gas started flowing, the furnace worked perfectly, starting and stopping exactly as it should. I plan on buying another Dinosaur board to install in my rear furnace - I feel it is much superior to the 20+ year old OEM board.
Picture below shows the furnace housing "gutted" after I removed the motor, fans, gas valve and burner assembly. Disassembly only requires common hand tools and common sense - nothing difficult. There was a heavy buildup of dust and dirt in the fans and blower housing, which I cleaned out with brushes and blow gun. I also oiled the bushings on the motor, cleaned the ignitor electrodes, and adjusted the gap to 1/8". The other photos show the old burner (compare to photo in Amazon ad).
I hope this writeup encourages others to tackle this project!
@Chuck Thanks for the great write up. I went thru the same situation a couple of months ago.
Here is my equally long reply. Grab another cup of coffee ya'll.
My rear furnace showed carbon buildup on the exhaust flue. I had Oregon Motor Coach look at it and they blew some air through it and said they got rid of a lot of crap in the flue. They also cleaned up the exhaust flue and hornet screen. Used the furnace a couple of times and carbon came back.
Back in May of this year (2014) I had Foretravel look at it. They couldn't find anything and the next step was to pull the furnace to check it out. About 3 hours labor. It was the rear furnace that is also responsible for keeping the water bay from freezing so gave them the ok. They found the same as you a rusted out burner. Also a 32811. They said burner no longer available but the parts department was able to find a third-party replacement burner. They installed it and replaced the furnace. I tested it a few times and seemed to work fine.
Fast forward to October in Colorado and try to use the furnace. It works sometimes but refuses to light sometimes and other times sounds like it's backfiring. Call the LP Appliance guy that works the park and he does a lot of checking and then pulls the burner out without pulling the furnace as Foretravel said they needed to do. About 4 screws and disconnect the LP flange. He says it's the wrong burner and says he can get me the right one. He makes a couple of calls and comes back and says not available. Need a new furnace for $800! He also put a meter on to measure water column and when he pulled the screw to install it he heard gurgling. Thats when I found fluid in my LP line. See my post here. LP Maintenance (http://www.foreforums.com/index.php?topic=22796.msg) After we drained the line the furnace worked much better but still did the backfire thing. Usually when I was in a deep sleep at about 3:00am. Flap, Flap, Flap! Was the noise it made.
I pulled the burner on the front furnace to install on the rear furnace for troubleshooting purposes and turns out the front furnace burner is as bad as the rear one but it was working fine! Installed in the rear furnace anyway and still got the flap, flap, flap sound every once in a while. Installed the burner that FOT installed in the rear furnace in the front furnace and it worked but every once in a while I get a no light and it would just recirculate air until I turned it off then on again. :( Didn't know the Dinosaur board would try to relight. That's a great feature!
Finally got tired of screwing around and concerned about safety and ordered a new furnace. I went with the new two stage Atwood Excalibur XT Furnace, 23,000-34,000 BTUs from Excalibur XT Furnace, 23,000-34,000 BTUs - 3.59 (http://www.adventurerv.net/excalibur-furnace-2300034000-btus-p-8601.html). Was a pretty easy install.
The 2 stage is a big upgrade from the old furnace. It almost always runs in the low speed mode which is much quieter and more comfortable since it's blowing less hot air. (hope that makes sense!) I'm planning to replace the front furnace soon for this same reason.
Glad you had better luck than I did with the replacement burner. I was planning on doing a write up on the furnace install but there was a cold front coming and I forgot to take any pictures! I'll do a write up when I replace my front furnace. Here are some pics of the old furnace showing the carbon buildup, the old burner & new burner.
see ya
ken
EDIT:
Forgot to mention that I still have the old furnace and will bring it to Quartzite. It's a 8535-II. If your going to be in Quartzite and you need any parts let me know. The controller is original and still works. The motor is a little over a year old.
Ken,
"Excellent write-up" right back at you! I don't have any of that black sooty looking residue on either of my units - it looks like yours was "running rich" for quite a while. I know it is important to check the gas delivery pressure at the furnace valve (should be 11" of water, according to what I've read). I haven't had that done, but plan to when I get the opportunity. All of our propane appliances (now that I have fixed the furnace) seem to light off quickly and burn real clean, so I don't THINK we have a gas pressure problem. THANKS for reminding me about your post concerning oil in the rubber propane line. I read that post a while back, then promptly forgot about it (Oldtimer's disease...). I will go out today (while it is 75 degrees and sunny) and check for liquid accumulation in the gas line.
The replacement burner on your old furnace (in the photo) looks to be much closer in design (to the original) than the one I purchased. I know there are several variations on the burner design, and have read that the burner CAN have a big influence on furnace performance. I'm putting faith in the "expert" opinions I got, and hope the burner I fitted will do the job properly. We are scheduled to have a pretty cold night here on Monday, so I will get a chance to try it out under actual cold conditions. I did notice that the air flow out of the front vents seems much more "vigorous" since I cleaned the fans and fan housing, and oiled the motor.
Besides the ever-troublesome mud dauber nests, other things that can affect the furnace performance are combustion air flow, and size and condition of the gas orifice. Air flow is a function of fan speed and fan effectiveness. A slow moving or dirty fan will not supply sufficient air for complete combustion. In addition, each furnace model calls for a specific gas orifice size. If the orifice is a incorrect part number, or if it has been damaged or reamed oversize by incorrect cleaning, the gas/air mixture can be thrown way off. Either of these things might have caused the sooty condition of your old furnace.
Without a doubt, upgrading to a modern furnace would be a nice move. I'm sure they are more efficient and all-around "better". However, as long as I can keep the old unit running safely, and it keeps us warm in our limited cold weather operations, I will hold off on the retrofit. Got to prioritize the use of available funds, you know!
We haven't decided yet about going to Q... but Thanks for the offer on parts. My furnace motors are both in good shape. The front motor was replaced in 2003, and the rear motor (and burner) were replaced in 2012 by the PO (Thanks John!!!). Do take the old unit with you to Q - never know when someone might need a part!
Well, I just went out and disconnected the rubber hose below the propane regulator. The hose is definitely the low point in the line - everything is uphill from there. So guess how much oil I got out of the line... NOTHING. Zero, zilch, nada...not even one single drop. I'm not sure what that means, but I guess it's a good thing. I suspect our coach has seen very limited cold weather operation in its lifetime, so perhaps not a lot of propane has flowed through the hose. Or the PO may have already drained the line - I'll have to ask him. Anyway, that's one more thing I can cross off my to-do list!
@Chuck Good news. One less thing to worry about now. :)
see ya
ken
Ken, are you required to change over to the Atwood thermostat or can you reuse your existing thermostat? I'm really thinking of upgrading to the Atwood 2 stage.
@Robert The Excalibur 2 stage requires the new Atwood thermostat. It's a pretty easy install. The thermostat requires 1 hot 1 ground and 1 thermostat wire from the furnace. Be sure to connect to the + thermostat wire on the furnace. It comes with a + wire and a - wire but no instructions on which to use. Called Atwood and they said to use the - wire to the thermostat. Eeeent... fail! Switch to the + wire and it fired right up.
see ya
ken
Just thinking out loud: I wonder if the oil in the line is the cause of the black soot in the burner area? If the oil made it to the main supply hose (from the Vapor connection of tank) it seems like it could go further in the lines. Burned oil is known to be sooty.
@John hadn't thought of that but definitely a possibility.
see ya
ken
Thanks to both Chuck and Ken for excellent posts. It's great to find this level of detail and photos when doing a search for a problem. Also nice when the thread doesn't go off hopping down a rabbit trail or into personal exchanges as often happens.
jor