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Atwood (now Dometic) Hydroflame Furnace replacement

 Now that Atwood has been absorbed by Dometic and they have jiggered their LP furnace model lineup, has anybody installed one of the "New and improved ??? " models in place of the Hydroflame 8535 series III's? Dometic killed the two stage Excalibur XT models which was my preferred replacement option, so now the choice is to try and source the correct parts and return to the former status quo (noisy, but effective) or identify a possibly improved replacement unit with the Dometic nameplate. The issues with the later option include form factor (physical size, location of the vent, ducting, etc.), and whether or not or painted furnace door will fit (mainly an issue with the vent location), and finally, whether it will be controlled by the existing Dometic thermostat. It appears from the published dimensions that the "Dometic AFMD35111 35,000 BTU Medium 12VDC Furnace" will mount the same and from the image on Dometic's website, it looks like the vent is in a similar location... but, how to be sure? Link to Dyers RV Parts and Accessories product page;
Dometic AFMD35111 35,000 BTU Medium 12VDC Furnace - Furnaces - Furnaces - RV...
I guess I waited too long to pull the trigger on the Atwood two stage Excalibur XT, since I was unable to even find any new old stock examples... maybe for the best, I tell myself ::) .
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #1
No responses to my question, so I guess I may be the guinea pig on figuring out what to replace the original Hydroflame 8535 III furnace with. One thing I see on the Dometic products is that the LP connections are on top with a tube assy that connects at back of the unit. That can be worked around easily enough. The main problem I can see is that the doors are completely different, but I think I can adapt our painted door assembly to the newer units, but without a CAD drawing, it is difficult to tell if the vent is in exactly the same place. It looks like it must be close, but close enough? Hmm... another possibility is new old stock Excalibur (name change from Hydroflame?) there are so many model numbers which appear to have the same form factors with the LP connection on the side and the tabs which hold on the bezel for the door hinges. There are a few out there with the same model number except that they are a series IV, i.e. 8535 IV. They look identical, and are likely a drop in replacement. However, I have found one new old stock Excalibur XT two stage 25/40K BTU... still thinking, but the unit is physically larger, though still has the same size cut out. The exterior portion of it has a taper on the top and bottom, but the bulk of it is 9 ⅛" high as opposed to 7". The attached pictures should make that clear. It is quite a bit deeper however, apparently 23 ½". In measuring the space where the furnace goes, I can make it fit. I may have to "adjust" the 2" utility bay duct penetrations to accommodate the depth of the unit. The drain pipes from the kitchen sink run along the floor at about 24" from the outside wall, so they should just clear the furnace plenum. I will have to fabricate new supports, but that won't not be a problem. The real difficulty is just the risk of getting a fairly expensive piece of gear without the cushion of a factory guarantee should it be DOA. On the other hand, these are fairly simple beasts and the parts are readily available... decisions, decisions ::) It would be easier if I wasn't so slammed with priority projects to get ready for an 8 to 10 month trip starting at the Quartzsite gathering. I will post my resolutions as I go.
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #2
I'm watching, as a new furnace is in my future. Glad your the guinea pig.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #3
Yea Don..Thanks for taking one for the Foreforums Team..

Mark
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Mark and Tanya
Milton , Florida
US Navy Veteran (DV)
1999 U270 Special 40' CAI , 2015 Jeep Wrangler Sahara

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #4
Thank you and look forward to your project. Always a outstanding write up with easy to follow pictures.
John
1998 U270 34'

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #5
Don I have run a heating and cooling load on my coach and the furnaces are way oversized for my motorcoach at -5,  probably based on RIVA standards for a POS typical  1.5" of batt insulation TT that arrives at a campsite with the interior at 40 or less. My 35000 btuh input front heater cannot produce even 18000 btu per hour because it shuts off on high limit temperature safety switch after about 10 minutes, cools off and only then restarts. I have (4) 4" diameter supply vents on the front furnace. Just simple physics due to lack of airflow. Smaller 18k  bedroom unit is much quieter due to it's lower speed fans. If I was using the coach regularly in cold weather I would buy a 12k btuh for the rear and move 18k to the front. Reworked the ductwork on both furnaces to get better airflow which helped.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #6
Here is an update on the Atwood Hydroflame furnace replacement process. I have ordered the NOS Atwood 2540 DCLP from an outfit called Tristate Surplus out of Michigan. I first saw the item as a result of one of my followed eBay searches, but I found their business website as the result of a web search and discovered the same item. So I called them this morning to get a feel for their operation, since this is an NOS item, there is no warm fuzzy return option (not that returning a large 45lb. box is fun!). Anyway, I spoke to a nice lady who told me that their tech goes through everything to make sure that the items are in working condition. She let me talk to the tech which went a long way to reassuring me about the condition of the furnace. He mentioned that since Dometic had absorbed Atwood, he was working on ironing out a lot of engineering issues on Dometic's furnace offerings. He stated that things were improving but that the transition to the new product lines was far from smooth. His opinion was that Atwood was a more quality oriented company than Dometic. Interesting tidbit that before Atwood was bought out by Dometic, Atwood developed the helium based absorption fridge that was promptly axed when Dometic acquired Atwood. In any case, as these LP furnaces these are relatively simple beasts and parts are still available, I decided to pull the trigger on the Atwood 2 stage 25/40K BTU furnace. I may add a couple more 2" ducts for the basement to allow for more air flow through the unit, but I am hoping that the furnace will operate on the low setting most of the time. If they had had the next size down (23/34K BTU), I would likely have opted for it just because the smaller physical size (matches the old one) would have required less adjustment in the furnace compartment.
On a side note, buying the unit from the website as opposed to eBay, resulted in a lower total cost (probably because the seller will have no eBay or PayPal fees). Additionally, the seller's website offers free ground shipping to the lower 48. The $100 lower price shown on the website vs. eBay along with the free shipping saved a whopping $160 over what the buy it now price on eBay would have been.
I will update this thread as I learn more and post pictures of the unit I receive.
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #7
Here is an update on the Atwood Hydroflame furnace replacement process. I have ordered the NOS Atwood 2540 DCLP from an outfit called Tristate Surplus out of Michigan. I first saw the item as a result of one of my followed eBay searches, but I found their business website as the result of a web search and discovered the same item. So I called them this morning to get a feel for their operation, since this is an NOS item, there is no warm fuzzy return option (not that returning a large 45lb. box is fun!). Anyway, I spoke to a nice lady who told me that their tech goes through everything to make sure that the items are in working condition. She let me talk to the tech which went a long way to reassuring me about the condition of the furnace. He mentioned that since Dometic had absorbed Atwood, he was working on ironing out a lot of engineering issues on Dometic's furnace offerings. He stated that things were improving but that the transition to the new product lines was far from smooth. His opinion was that Atwood was a more quality oriented company than Dometic. Interesting tidbit that before Atwood was bought out by Dometic, Atwood developed the helium based absorption fridge that was promptly axed when Dometic acquired Atwood. In any case, as these LP furnaces these are relatively simple beasts and parts are still available, I decided to pull the trigger on the Atwood 2 stage 25/40K BTU furnace. I may add a couple more 2" ducts for the basement to allow for more air flow through the unit, but I am hoping that the furnace will operate on the low setting most of the time. If they had had the next size down (23/34K BTU), I would likely have opted for it just because the smaller physical size (matches the old one) would have required less adjustment in the furnace compartment.
On a side note, buying the unit from the website resulted in a lower total cost (probably because the seller will have no eBay or PayPal fees) as well as free shipping, saving a whopping $160 over what the buy it now price on eBay would have been.
I will update this thread as I learn more and post pictures of the unit I receive.
Don

Thanks Don for the amazing thoroughness of your project...  we have an 86 GV with the front and rear Atwood furnaces. Front living room furnace is in good working condition but we are unable to get the bedroom small unit to light up.... we will continue to watch this post and see your progress.  We agree with your comments about BTU needs.  We have been using JUST the living room unit to heat the entire coach with no issues here in Colorado
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #8
Concerning the bedroom unit.  The biggest problem with those heaters is the Sail Switch, it is located to the rear under the top cover, has 2 wires attached, you can access it by removing the cover and removing the bottom drawer.  Look for a wing nut that holds the switch, remove it and remove switch, cycle it by hand that might be all that's needed.
1988  40' Grand Villa Cat 3208t

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #9
I've had both Atwood and Dometic units for over thirty years. They all have a life-span, especially when one full times. Case in point: when we got this coach, the files said, "Overhaul rear Atwood furnace 11.01." It went out last year, and, upon taking it apart, it was at the end of it's service life, and was replaced with fresh. The ignitors are easy to replace, but, at 10 years, or so, it's time for fresh.  ^.^d
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #10
Fortunately, most all the components are replaceable and should continue to be. I replaced a 15 year old motor this rear.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #11
Just DIY replaced the old Atwood with a Suburban two stage furnace. See photo. Had to make an adapter plate out of aluminum, and even made an improvement by making an overhang to prevent water from entering the intake and exhaust ports. See Tim's RV Tips #10 - Relay box to use Ecobee4 Thermostat in an RV - July 6,...
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #12
Here's the other photo. This two stage furnace, Model SHD-2542Q (25,000 and 42,000 BTU, the Q=Quiet) is very quiet on the 25,000 BTU stage.  Almost can't hear the flame.

Other improvements are:

- Modified old Atwood faceplate to suit the Suburban. It's just some sheet metal mods. I did this because the my two-stage Suburban is no longer manufactured  (but it is supported) and the RV faceplate is unavailable.

- Cut two aluminum straight pieces of metal to mount the front of the new furnace to the Foretravel's wood frame opening. It mostly fit fine.

- Modified the plenum at the rear of the Atwood to better insert the Suburban. This plenum is for three two inch ducts for the basement.  This was easy work for an amateur sheet metal worker like me, but it was hours of work fitting the old plenum
box to fit just right. The other six existing ducts and return duct system fit just fine.

- Added insulation to front of furnace because when the furnace is not heating, there was no insulation on the front of the furnace. Now there is about R6 insulation. Not a lot, but better than nothing.

- Sealed furnace to Foretravel chassis with EPDM gasketing from Frost King from Home Depot. EPDM is a high quality high-temperature material. The old Atwood used GOBS of silicon seal, which leaked and was very difficult to remove.

- Added a Ecobee 4 WiFi smart thermostat, with Alexa voice interface (when connected to WiFi) with relay box and 24VAC transformer.

It's working great after five months, even in 20 degree F temps. It no longer ROARS like the old Atwood beast.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #13
Interesting, it seems that Suburban discontinued their two stage version around the time that Atwood got acquired. It is hard to tell though, a lot of RV parts places still have the Atwood two stage furnaces on their web sites, but when contacted they say they need to change their website to reflect that the units have been discontinued. Your replacement shows that where there is a will, there is a way!
Don
Here's the other photo. This two stage furnace, Model SHD-2542Q (25,000 and 42,000 BTU, the Q=Quiet) is very quiet on the 25,000 BTU stage.  Almost can't hear the flame.

Other improvements are:

- Modified old Atwood faceplate to suit the Suburban. It's just some sheet metal mods. I did this because the my two-stage Suburban is no longer manufactured  (but it is supported) and the RV faceplate is unavailable.

- Cut two aluminum straight pieces of metal to mount the front of the new furnace to the Foretravel's wood frame opening. It mostly fit fine.

- Modified the plenum at the rear of the Atwood to better insert the Suburban. This plenum is for three two inch ducts for the basement.  This was easy work for an amateur sheet metal worker like me, but it was hours of work fitting the old plenum
box to fit just right. The other six existing ducts and return duct system fit just fine.

- Added insulation to front of furnace because when the furnace is not heating, there was no insulation on the front of the furnace. Now there is about R6 insulation. Not a lot, but better than nothing.

- Sealed furnace to Foretravel chassis with EPDM gasketing from Frost King from Home Depot. EPDM is a high quality high-temperature material. The old Atwood used GOBS of silicon seal, which leaked and was very difficult to remove.

- Added a Ecobee 4 WiFi smart thermostat, with Alexa voice interface (when connected to WiFi) with relay box and 24VAC transformer.

It's working great after five months, even in 20 degree F temps. It no longer ROARS like the old Atwood beast.
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #14
I should point out, the Atwood two stage furnaces requires a different thermostat and won't run off of the Dometic DuoTherm thermostats. Fortunately, the NOS unit I bought includes an Atwood digital thermostat with it, saving $100 or so. I won't mind having a thermostat dedicated to the furnace though, it allows the option of running the heat pumps at the same time... I got the shipping notification and the unit is scheduled to be here next Wednesday. Fingers crossed, knock on wood, etc. that it arrives on time, safely, and is fully functional!
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #15
I may add a couple more 2" ducts for the basement to allow for more air flow through the unit, but I am hoping that the furnace will operate on the low setting most of the time. If they had had the next size down (23/34K BTU), I would likely have opted for it just because the smaller physical size (matches the old one) would have required less adjustment in the furnace compartment.
Don


I've got the 25/40 Excalibur and while my RV is a couple of feet shorter than yours, it nearly always runs in the 25k btu mode.  In fact, the only time it ever runs in 40k high mode is when the thermostat temperature is more than IIRC 5 degrees from the setpoint which has never happened to me during normal operation.  The furnace is pretty damn quiet running in 25k btu mode and just as loud as my old single speed furnace in 40k mode.
Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #16
Agreed, no more "blast furnace".

BTW, a 2 stage furnace will operate fine with the old thermostat on the low stage but not on the high stage. An owner could add any two-stage RV (millivolt type) thermostat. You only need to use the R amd W1 wire. I did this with a simple $15 Suburban thermostat as a backup to the Ecobee 4, which needs 115VAC / 24VAC to operate. When boondocking, the furnace will work when the inverter is off.

Nice find on getting an Attwood 2-stage. I could not find one. I wonder why Dometic decided to retire the two stage models, when they are the quietest furnaces on the market, yet can produce enoigh BTUs on high stage to warm the rig even on the coldest nights. Seems counterintuitive.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #17
Tim, we have  an Ecobee in our home and love it. Nice to have the wi fi control.
They seem to be good units.
JohnH
Coachless, now use aircraft.
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #18
Good to know... the tech I talked to told me that the two stage required a different thermostat, but he didn't say why. I will try it with the Duotherm first to see if will run on low with it. I will install the Atwood digital thermostat bundled with it for now and investigate other thermostat options later.
Don
Agreed, no more "blast furnace".

BTW, a 2 stage furnace will operate fine with the old thermostat on the low stage but not on the high stage. An owner could add any two-stage RV (millivolt type) thermostat. You only need to use the R amd W1 wire. I did this with a simple $15 Suburban thermostat as a backup to the Ecobee 4, which needs 115VAC / 24VAC to operate. When boondocking, the furnace will work when the inverter is off.

Nice find on getting an Attwood 2-stage. I could not find one. I wonder why Dometic decided to retire the two stage models, when they are the quietest furnaces on the market, yet can produce enoigh BTUs on high stage to warm the rig even on the coldest nights. Seems counterintuitive.
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #19
I have the 25/40 Excaliburs. (2 in my 40fter) I installed about 5 years ago IIRC. Have never needed the 40,000btus. Always runs on 25,000. That includes a recent stay in Denver for the month of November. Had some nights in the low teens. I have mine set to only run on 25,000. I like that it's a more gentle air blowing on me instead of a the blast furnace on high. It does run longer when in low speed mode but since it's quieter I don't mind.

The thermostat is not your usual on/off switch thermostat. The thermostat needs to communicate more information than a simple on/off provides. It does this IIRC via variable voltages sent to the furnace controller. That is a proprietary interface so only Atwood (maybe Dometic now) thermostat will work.

The thermostat is my biggest complaint with the unit. Both of my units failed soon after install. They would spontaneously turn the fan on for no reason. Atwood replaced both of them. The retail on them was around $180! Now my beef with them is the slider switch for Cool, Off, Heat, Fan. It is very sensitive and you have to have it positioned just right to work. I leave mine on heat all the time and control on/off via the temperature settings. The switch is a simple 4 position slider so hopefully they improved it in later generations of the thermostat.

Let us know if you experience a similar issue. Hope you don't!

see ya
ken
 
The selected media item is not currently available.ken & dori hathaway & Big Agnes
🍺1992 U300 GrandVilla WTBI #4150 FOT FBP 2011
✨6V-92TA DDEC Parlor Coach 350HP Series 92
🏁2011 Nissan XTerra Pro-4X

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #20
Good info Ken... For-warned. Maybe a master switch that interrupts the power to the thermostat will save wear and tear on that slider switch. When I looked at pictures of the Atwood digital thermostat, I could see that the slider switch would be a hassle to manipulate. I had already considered putting something to block of the cool position on the slider since I will be using the Duotherm thermostat to control the A/C's.
Do you recall whether the the depth of the unit was an issue with the installation? I am assuming that your 25/40K BTU unit is the same dimensions as the one I am getting (16 ½" "W X 9 ⅛"T X 23 ½"D). I am not sure if the two stage unit I am getting is indeed the Excalibur XT as the only info I have on the model number is 2540 DCLP.
Don
The thermostat is not your usual on/off switch thermostat. The thermostat needs to communicate more information than a simple on/off provides. It does this IIRC via variable voltages sent to the furnace controller. That is a proprietary interface so only Atwood (maybe Dometic now) thermostat will work.

The thermostat is my biggest complaint with the unit. Both of my units failed soon after install. They would spontaneously turn the fan on for no reason. Atwood replaced both of them. The retail on them was around $180! Now my beef with them is the slider switch for Cool, Off, Heat, Fan. It is very sensitive and you have to have it positioned just right to work. I leave mine on heat all the time and control on/off via the temperature settings. The switch is a simple 4 position slider so hopefully they improved it in later generations of the thermostat.

Let us know if you experience a similar issue. Hope you don't!

see ya
ken
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #21
Do you recall whether the the depth of the unit was an issue with the installation? I am assuming that your 25/40K BTU unit is the same dimensions as the one I am getting (16 ½" "W X 9 ⅛"T X 23 ½"D). I am not sure if the two stage unit I am getting is indeed the Excalibur XT as the only info I have on the model number is 2540 DCLP.
Don

The depth was not an issue but I seem to recall having to move (and maybe modify?) the riser feet that my old furnace sat on to get it lined up correctly.  It wasn't a direct replacement but it also wasn't a whole lot of work to make it fit.  You will need to change the wiring and IIRC I had to run a 4 wire cable to my thermostat location since the old furnace was switched from my front AC unit and that isn't how the Excalibur is set up.

Edit:  actually I'm remembering that depth was an issue when trying to get the unit into place.  It is an awkward installation and I ended up having to dismantle the bottom cabinet drawer framing inside the cabinet temporarily  to get the unit into place.  It was all stapled together and came apart easily once the staples were removed.  Once the new furnace was put in place, all the bottom cabinet framing was screwed back together.  This may or may not relate to your installation since I'm not sure about the location of your furnace.  Mine sits under the countertop of my L shaped kitchen layout in the empty (and hard to access) area between the sink and cabinets/cooktop. 
Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #22
I had no trouble with my install. Fit perfect. I did beef up the rear support on the rear unit but it was just a matter of using a bigger block of wood to hold up the rear. Did I just use the word rear 3 times in one sentence? :) That said every Foretravel is a little bit different so YMMV. With your skills I don't think there will be an issue.

see ya
ken
The selected media item is not currently available.ken & dori hathaway & Big Agnes
🍺1992 U300 GrandVilla WTBI #4150 FOT FBP 2011
✨6V-92TA DDEC Parlor Coach 350HP Series 92
🏁2011 Nissan XTerra Pro-4X

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #23
Two comments:

1. Heater control
The Suburban SHD-2542Q does not have a digital control. It uses simple a on-off connections between the R and W1 wires for low stage engagement. For stage 2, connect the R and W2 wires.

2. Ecobee 4 report
See the photo below for a report of the Suburban heater usage. I love to see how the furnace maintains cabin temperature versus outside air temperature.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Atwood (now Dometic) Hydroflame Furnace replacement

Reply #24
PS: I just installed this dumb thermostat beside the smart one. That way, if the smart one stops working, the dumb thermostat will engage the low stage (stage 1) heat by connecting the R and W1 wires.

It looks dumb, but is REQUIRED for inverter-off operation and keeping pipes from freezing.

You may ask: What is heating your rig now in these 20 degree Northeast US temperatures?
I have a quartz electric heater in the cabin, with a box fan), and Frost King strip heaters in the basement, all thermostatically controlled.

Temperatures are monitored by an Acurite Smart Hub system to ensure the water pipes and battery are kept from freezing.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.