Alpine Furnace

[Ddubya]

I am in a 2017 Alpine 3401 in south Texas and the temp dipped to the lower 30's the last two mornings.(I know Boo Hoo) The furnace ran most of the time and while the bedroom remained warm the kitchen and living room are cold.
What I have discovered is that there are two floor vents in the living/kitchen area and one in the bath and one in the bedroom. Bath and bedroom vents are about 8 inches apart.
Having looked at the furnace installation it appears that the ducting from the furnace is not installed according to Atwood's specifications. Atwood requires 36 square inches of duct for proper operation of their 35000BTU unit. Alpine has one 4 inch duct feeding the entire interior of the trailer and one 2 inch duct feeding the belly storage for a total of about 16 square inches. I plan to speak to my dealer about this when I return home but I doubt they or Alpine will attempt to do anything.

[JRTJH]

The furnace plenum has duct openings on the bottom as well as on the sides and the end. You might want to double check to see if there are two additional vent hoses connected "below the floor" that service the two "main floor vents" in your main cabin. That's the way the heating ductwork in my Cougar is "plumbed". Maybe yours isn't, but often times the ducts go "down into the basement" rather than make a 90 degree turn immediately after the plenum connection.

Added: According to the Atwood Furnace Installation Guide, a "common 4" circular duct" satisfies the need for 12 square inches, so three "common 4" ducts" plus the 2" duct is considered "adequate" venting capacity. So, if the two "main cabin floor vents" are ducted below the furnace plenum, the minimum capacity is being met.

[tdawg]

In my Alpine the bathroom furnace duct would blow so much air i pulled vent diffuser off and blocked off 3/4 of it with aluminum tape, that balanced more air to rear ducts.

[Ddubya]

I will check to see if it is ducted on the bottom but doesn't appear so. There is very little air from any of the vents.
It also looks like one continuous plenum from the back of the living area to the front bedroom. I am on a month long shake down so when I return I will be able to open it up and see how it is plumbed.

[issyrog]

can you hear your fan. check tstat?

[Ddubya]

OH yes, fan is on, tstat works fine

[bsmith0404]

Don't you have a dual zone thermostat? Yes the heating between front and rear is not perfect, we actually end up running our front AC at times when the rear is being heated. I know that doesn't make for a very efficient system, but it balances out the temps. The dual zone set on auto works well. As the front gets a little too warm the AC will kick in for just a bit to keep the temps down and comfortable. The first few times we used our 5er, the front would be too hot or the rear too cold, but this works to keep the entire trailer comfortable. I haven't done it yet, but I do plan to change out the vent covers with adjustable ones so I can shut down the airflow to the front a bit, especially in the bathroom. As far as the ductwork goes, it works so I'm not going to dig in and start trying to make changes.

[Ddubya]

Some good points. Thanks.