blown fuses in new FWC Hawk Atwood furnace

[Wallowa]

I think the new furnace is about the same heat output - just twice the electrical consumption. My 2016 uses the Atwood 8012-II furnace - 12000 BTU/h input, 1.8A current draw (it is actually more like 1.5A on mine): https://www.vintagetrailersupply.com/v/vspfiles/assets/images/hydroflamemanual.pdf

The new Dometic replacement is this one (I think) also 12000 BTU/h but at 3.4A current draw:
https://www.dometic.com/en-us/us/products/climate/furnaces/furnaces/dometic-small-furnace18523

The inrush current is the initial current spike needed to start up the blower motor or charge the ignitor. This is what pops the fuse, the average current is much lower (3.4A).

Thanks...very informative...still wondering why FWC went to a furnace that uses twice the amps for same BTUs....but as the old saying goes: "I got mine"!

 

[klahanie]

^ I notice in both eras that Atwood/Dometic made a "standard" and low amp draw version for the 12K size (used this manual for current/new Dometic).

"old" 7912 @ 3.4A, 8215 @ 1.8A
"new" AFSD1211 @ 3.4, AFSAD12111 @ 2.4

I'm thinking the amp rating difference within each series is because one furnace is designed for discharge ducting and the other is not.

Interesting to me is the LPG efficiency for all is no better than my old 16K unit (~76%). I seem to remember the story years back that the switch to 12K was partly because of the improved efficiency rating of LPG. (those who have a low amp version, consider yourself lucky !)

Agree with Advmoto18 on getting fuse change in writing from Dometic.

Per literature found on the FWC website, https://fourwh.com/New_2017_Four_Wheel_Popup_Campers_Owners_Manual.pdf

This limited warranty does not cover defects in materials and workmanship or any other damage to or caused by truck camper components manufactured by companies other than Four Wheel Campers (example: refrigerators, furnaces, hot water heaters, awnings, roof racks, camper jacks, propane tanks, etc).

It would blow (pun intended) to damage the furnace because fuse protection was removed on the suggestion of someone who may provide no warranty. - that kind of risk is what the internet is for !

 

[Old Crow]

I think the new furnace is about the same heat output - just twice the electrical consumption. My 2016 uses the Atwood 8012-II furnace - 12000 BTU/h input, 1.8A current draw (it is actually more like 1.5A on mine): https://www.vintagetrailersupply.com/v/vspfiles/assets/images/hydroflamemanual.pdf

The new Dometic replacement is this one (I think) also 12000 BTU/h but at 3.4A current draw:
https://www.dometic.com/en-us/us/products/climate/furnaces/furnaces/dometic-small-furnace18523

-snip-

I took this photo of the front page of the furnace manual in a new Fleet at the New England FWC dealer last month.

(Click to enlarge)



Unfortunately, it doesn't tell us if the 12,000 btu furnace in the camper is the SA or S model.

This AF-Series Technical Installation manual of 5/2014, page two, Model Nomenclature section, says the S means small cabinet size and the SA means small cabinet size, low amp. Interesting!

This SA model at Panther RV says that one has a 2.4-amp draw while the Dometic listing for the AFSD12 says that one draws 3.4 amps.

I'm pretty sure the one used in FWC campers is the S model but I also thought it interesting another lower-draw version exists (or did exist for a while).

Edited to add-- Looks like klahanie posted while I was still creating mine. Note to self: Read the thread one more time before posting!


.

 

[klahanie]

^ Great minds, eh OC !

I wonder if the "direct discharge" .. my layman's term .. design of furnace is quieter (as well as lower amp rating, if I have that correct) . I think I remember reduced noise being another stated benefit of one furnace model replacement made by FWC at one point in their production history.

 

[CementTruckUT]

This is an old post, but can anyone (maybe Stan?) confirm that in a 2018 Fleet the heater fuse should be 15A, and not 7.5 A? I blew a couple fuses last weekend, granted my battery was a bit low due to cloudy, rainy conditions and not being charged by my truck, but I want to make sure 15 A is safe before changing the fuse out.

 

[pvstoy]

My 2015 Hawk flatbed shows 7.5a fuse.
.

 

[CementTruckUT]

Thanks pvstoy! Yeah, mine says 7.5 A too, but it's a 2018 and I was wondering if it should actually be a 15A from reading the rest of this thread. I'd love to swap in a 15 A but I don't want to damage any wires or anything.