Replacement for AFMD35121 Furnace in 2018 Keystone Cougar 27SAB

Question

Question:

what is the replacement furnace for an AFMD35121 from a 2018 keystone cougar 27SAB?

asked by: Harvey B

0

Expert Reply:

Hi Harvey; the DFMD35 series (same as your AFMD35121) has been discontinued. This leaves you with two options. You can either downsize to a 30k Btu unit or move up to the 40k unit. The 30k will fit in your existing space but you will have a little less heat.

If you go up to the 40k unit it will probably require enlarging your opening since it is 2" taller. You also need to match door for door or doorless for doorless when choosing the replacement. The 40k units measure 20" deep x 9" tall x 16-1/2" wide and cutout varies based on the door as seen below.

You can choose from the following based on Btu, door/doorless, and door color:

-Dometic RV Furnace - LP Gas - Automatic Pilot - 12V DC - 30,000 Btu - White Door # DMC98RR

-Dometic RV Furnace - LP Gas - Automatic Pilot - 12V DC - 30,000 Btu - Black Door # DMC38RR

-Dometic RV Furnace - LP Gas - Automatic Pilot - 12V DC - 30,000 Btu - Doorless # DMC54RR

-Dometic RV Furnace - LP Gas - Automatic Pilot - 12V DC - 40,000 Btu - White Door # DMC68RR

-Dometic RV Furnace - LP Gas - Automatic Pilot - 12V DC - 40,000 Btu - Black Door # DMC48RR

-Dometic RV Furnace - LP Gas - Automatic Pilot - 12V DC - 40,000 Btu - Doorless # DMC72ZR

expert reply by: Robin H

0

Dometic Note on DFMD35s
(click to enlarge)

Dometic Furnace Door Cutouts
(click to enlarge)

Robin H.

12/15/2025

Hi Harvey, how did things go with replacing the AFMD35121 furnace in your Cougar? Did you end up choosing the 30k or the 40k Dometic model for your setup? Your update could make it easier for others facing the same decision.

Harvey B.

12/15/2025

@RobinH I got the 30K unit and it went in ok. I had to put a stainless plate on the outside because the old hole was larger than the new one and slightly off center. The 30K was plenty of heat.

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Answer 2

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