Atwood Furnace

[Tam2004]

Originally Posted by tdf-texas

There is a model that has bluetooth - settings can be changed using a phone app. But it is still wired to the A.C / heater control box.

The bluetooth symbol on the bottom differentiates it from the standard model.

Yes this is what our thermostat looks like and David at Escape confirmed it is hard wired. And the control box is in the air conditioner as you all know. I am happy to read this -- it was a nice (false) way to explain why our original furnace seemed possessed (no obvious reason or fix to keep it working consistently). BUT the new one is still working perfectly - no hiccups whatsoever. Thank you all for correcting this information.

[Brian B-P]

Originally Posted by rubicon327

What looks really promising is the new Truma VarioHeat.
...
www.truma.com/int/en/products/truma-heater/truma-varioheat-comfort.html

That looks like a nice and tidy package, with a bonus "E-kit" add-on electric heater which shares the fan and can be run in combination with the propane furnace. I haven't worked out the efficiency yet, but it can't be worse than a typical RV furnace.

[tdf-texas]

Originally Posted by John in Santa Cruz

actually, the communications isn't 'digital', its the same on/off switch on a pair of low voltage wires to the heater... only the display and thermostat guts are digital.

The Dometic CT thermostat has three wires that connect it to the LCD SZ control box located in the A/C unit. These three wires are 12v power, ground, and digital comm.

• Red/white wire to the 12V+ terminal
• Black wire to the 12V– terminal
• Orange wire to the "COMMS" terminal

The communications between the thermostat and the LCD SZ control box is a proprietary digital signal unique to Dometic. The thermostat will indicate "E1 - Loss of communication between CT Thermostat and module board" when digital communications is lost between the two.

The A/C and the furnace are both controlled by the LCD SZ control box.

[John in Santa Cruz]

Originally Posted by tdf-texas

The Dometic CT thermostat has three wires that connect it to the control module located in the A/C unit. These three wires are 12v power, ground, and digital comm.

• Red/white wire to the 12V+ terminal
• Black wire to the 12V– terminal
• Orange wire to the "COMMS" terminal

The communications between the thermostat and the control module is a proprietary digital signal unique to Dometic. The thermostat will indicate "E1 - Loss of communication between CT Thermostat and module board" when digital communications is lost between the two.

ah, yuck, I hate proprietary crap like that.

[tdf-texas]

Originally Posted by John in Santa Cruz

ah, yuck, I hate proprietary crap like that.

I went into how it worked as soon as I picked up my Escape - the geek in me couldn't help it. I now have the bluetooth version installed and love it. I can change the temp settings or turn it on/off from anywhere in the trailer.

[Tam2004]

Originally Posted by tdf-texas

I went into how it worked as soon as I picked up my Escape - the geek in me couldn't help it. I now have the bluetooth version installed and love it. I can change the temp settings or turn it on/off from anywhere in the trailer.

Well, you solved the problem of how many of us perhaps pounded a little bit heavily on the thermostat in frustration in the beginning when the furnace wouldn't work properly. We quickly learned to be very gentle in tapping the thermostat after the Dometic staff told us if we weren't careful the foam behind the front cover would get compressed and then it wouldn't work very well. I am glad to learn that the thermostat is hard wired. I called David to ask him how to get the electrical plug in below the sink to work after water dripped down and it tripped. I couldn't find the GFI - as you probably all know - and I now know - it is in the outside plug in. AAAARGH. I forgot that part of the briefing on trailer. That is when I asked him about the wiring on the thermostat. One bad theory of mine down the tube, so it was just gremlins in our first furnace. I should have burned incense and chanted.

[sclifrickson]

Originally Posted by Tam2004

Well, you solved the problem of how many of us perhaps pounded a little bit heavily on the thermostat in frustration in the beginning when the furnace wouldn't work properly. We quickly learned to be very gentle in tapping the thermostat after the Dometic staff told us if we weren't careful the foam behind the front cover would get compressed and then it wouldn't work very well. I am glad to learn that the thermostat is hard wired. I called David to ask him how to get the electrical plug in below the sink to work after water dripped down and it tripped. I couldn't find the GFI - as you probably all know - and I now know - it is in the outside plug in. AAAARGH. I forgot that part of the briefing on trailer. That is when I asked him about the wiring on the thermostat. One bad theory of mine down the tube, so it was just gremlins in our first furnace. I should have burned incense and chanted.

And maybe you should find a new RV technician. Or at least take what he or she tells you with a grain of salt going forward.

[rubicon327]

Originally Posted by Brian B-P

That looks like a nice and tidy package, with a bonus "E-kit" add-on electric heater which shares the fan and can be run in combination with the propane furnace. I haven't worked out the efficiency yet, but it can't be worse than a typical RV furnace.

As usual there is some conflicting info online even among Truma sources:

One source says:
• Efficiency: 98 % (Stage 1) / 96 % (Stage 2) / 94 % (Stage 3)
A sales website says: "Highest available efficiency up to 90%"

Either way it is much more efficient than the older Atwood 8012 furnace and newer Atwood/Dometic D/AFSAD12 models that I just calculated at 76%.

[Brian B-P]

Originally Posted by rubicon327

As usual there is some conflicting info online even among Truma sources:
One source says:
• Efficiency: 98 % (Stage 1) / 96 % (Stage 2) / 94 % (Stage 3)
A sales website says:"Highest available efficiency up to 90%"

Thanks.

It makes sense that efficiency drops at higher output, but even at the highest output it is pretty good.

Originally Posted by rubicon327

Either way it is much more efficient than the older Atwood 8012 furnace and newer Atwood/Dometic D/AFSAD12 models that I just calculated at 76%.

Yes, the traditional RV furnaces are shockingly inefficient... so bad that it hasn't been legal to sell a home furnace that inefficient here for decades. I always thought that the excuse was their compact size (limiting heat exchanger area and thus efficiency), but the Truma unit is small.

[Defenestrator]

The Truma unit (in addition to costing drastically more) seems to draw quite a bit more 12V power. I'm guessing the trade-off is a longer and tighter heat exchange and exhaust path plus higher air volume shoved through it, which means more air restriction and more power needed to move the air but more heat pulled exhaust to air.

[rubicon327]

Originally Posted by Defenestrator

The Truma unit (in addition to costing drastically more) seems to draw quite a bit more 12V power.

Regarding power I’m not so sure. 12V amp draw at the respective settings is 0.65, 2.75 and 5.4A. For comparison the current Dometic DFSAD12 furnace used by Escape (single speed) draws 2.4A. Because of efficiency differences the mid-stage of the Truma is comparable to the Atwood in capacity. That means we are really comparing 2.75A to 2.4A. But really the Truma also has a lot of flexibility in ducting around the cabin of an RV. To get ducting capability with the Atwood/Dometic you need the D/AFSD not the D/AFSAD. That furnace draws 3.4A. So the Truma is actually the winner in this regard. Also bear in mind that a well insulated Escape in moderate temperatures might cruise along on the Truma’s low setting drawing only 0.65A.

[Defenestrator]

Good point. I think the equivalent average heat output from the Truma would basically be ~2.6A rather than 2.4A, so only about 10% more battery power needed (it's 2.75A on medium, but that's ~9500BTU instead of 9120BTU). For some reason I was thinking the power requirements on the Dometic furnace were lower, on the order of 1.8A.

But that's on the largely equivalent medium setting. I suspect you're right and the low setting would be enough to keep a 19' Escape with the insulation package toasty down to somewhere in the 25-35F range, and it's significantly more power-efficient than the Dometic. Even below that temperature it could probably spend most of its time on low and rarely kick up to medium, so it'd take less overall battery than the Dometic.

The "high" setting of 5.4A is very inefficient in terms of 12V power, but I can't see using that for a few minutes in something the size of an Escape unless you're actually trying to hold it at sauna temperatures on a snowy day.

[rubicon327]

Originally Posted by Defenestrator

The "high" setting of 5.4A is very inefficient in terms of 12V power, but I can't see using that for a few minutes in something the size of an Escape unless you're actually trying to hold it at sauna temperatures on a snowy day.

In our trailers I see the high setting only as a warm up mode. Great to have when arriving at your destination after towing in cold weather. The three stages makes the Truma very effective at operating at a capacity closer to the load. Which should mean less propane use, less power use and less noise.

The 1.8A draw you remember is the older Atwood 8012-II furnace that Escape previously used before it was discontinued.

[Tam2004]

Originally Posted by sclifrickson

And maybe you should find a new RV technician. Or at least take what he or she tells you with a grain of salt going forward.

There are "bluetooth" Dometic thermostat's so on reflection I think he was talking in general. But, as we wended our way across the country - there were a lot of mechanics looking at our furnace and replacing parts and many conversations with Dometic. Our mechanic did us a huge favor by getting us a replacement furnace which I think should be an option for any furnace that doesn't work within a couple of days of pickup of trailer and doesn't work after the Sail Switch and "mother board" are switched out. Why should we have to keep fiddling with a brand new product? AND Dometic doesn't pay the mechanics enough for their trouble anyway. I am glad many of you can repair your own - seems like that is the only route to take!!

[sclifrickson]

Originally Posted by Tam2004

There are "bluetooth" Dometic thermostat's so on reflection I think he was talking in general. But, as we wended our way across the country - there were a lot of mechanics looking at our furnace and replacing parts and many conversations with Dometic. Our mechanic did us a huge favor by getting us a replacement furnace which I think should be an option for any furnace that doesn't work within a couple of days of pickup of trailer and doesn't work after the Sail Switch and "mother board" are switched out. Why should we have to keep fiddling with a brand new product? AND Dometic doesn't pay the mechanics enough for their trouble anyway. I am glad many of you can repair your own - seems like that is the only route to take!!

I’m glad that he helped you out and that you got your furnace finally fixed. However, even in the case of a Bluetooth version of the thermostat (which ETI does not sell or provide), the Bluetooth is not between the thermostat and the furnace. It’s only between the thermostat and your Bluetooth-capable phone, tablet or computer. If your mechanic told you anything different then he didn’t know what he was talking about, which is a disqualifier for a mechanic in my book.

[steve dunham]

Pulled my Atwood furnace today and replaced the sail switch and circuit board. ( Parts cost = approx $200 USD )
Furnace works now but for how long is anybody’s guess .
Took longer to repair the cabinet then fix the furnace
Evidently Escape does not drill pilot holes when using screws so the oak trim piece around the furnace and the cabinet face needed some glue and clamp time . Escape tried to fix the large splits in the wood by shooting it full of staples but the staples failed . Hopefully my titebond glue will hold .

[CharlesPou]

I read whole thread looking for control board info, didn't see it. I have 2018 Escape 21 with new style furnace with outside removable panel, I think model DFSAD12131. I think the sail switch p/n is 33063, and I ordered 2 (1 to use, 1 for spare). Anyone know the control board p/n? thanks

[tdf-texas]

Originally Posted by CharlesPou

I read whole thread looking for control board info, didn't see it. I have 2018 Escape 21 with new style furnace with outside removable panel, I think model DFSAD12131. I think the sail switch p/n is 33063, and I ordered 2 (1 to use, 1 for spare). Anyone know the control board p/n? thanks

Try AFSAD12131: the control board is an atwood 31501.


https://pdxrvwholesale.com/products/...31-tune-up-kit


https://pdxrvwholesale.com/products/...board-31501%20


If I were ordering a control board for the furnace, I would get the Dinosaur igniter board.


https://pdxrvwholesale.com/products/...ard-fan50pp%20

[CharlesPou]

so you saying my DFSAD12131 takes same control board as your AFSAD12131? I think the sail switch is different, maybe the boards are the same, I don't know? I looked at the dinosaur board instructions and maybe too complicated for me. I would prefer OEM that fits, no mods required. Anyone have a link to Dometic furnace detail parts diagram? thanks

[CharlesPou]

OK, I found parts detail at Dometic website, appears you are right, takes same control board 31501, thanks