Replacing Old Atwood Furnace AFDMD35121 In 2018 Keystone Carbon 357 With New Dometic Furnace

Updated 11/14/2026 | Published 11/13/2026

Products Featured in This Question

Dometic RV LP Gas Furnace - 35,000 Btu - 12V - Doorless/Not Intended for Exterior Access

(16)

$1567.49

Dometic RV LP Gas Furnace - 35,000 Btu - 12V - White Door

(12)

$1404.49

Dometic RV LP Gas Furnace - 35,000 Btu - 12V - Black Door

(12)

$1404.49

Question:

I have a 2018 keystone Carbon 357, looking to replace my furnace. The model number is AFMD35121, but it has been discontinued. What is the replacement for this model that is just a plug and play swap for it.

asked by: Oscar Z

Expert Reply:

Hey Oscar! I would go with the Dometic RV Furnace # DMC74MR as the best replacement for your discontinued Atwood AFMD35121 in your 2018 Keystone Carbon 357 RV. This is a very common setup for that older Atwood.

Both furnaces have the same 16-1/2" wide x 7" tall x 20" deep dimensions and similar heating capacities, so the new furnace will fit into the same space without any major modifications. The wiring and propane connections will be fairly straightforward as well, although some minor adjustments may be needed.

The # DMC74MR is designed for installations without an exterior access door, just like your original furnace likely was. However, if yours does have an exterior access door, we also have the # DMC67SR with a black door or # DMC47SR with a white door. Those have slightly different dimensions, so you'll want to verify the opening before ordering.

Is your current furnace serviced from inside the camper, or does it have a large exterior access door?