central heating air flow ?

[Gertrude]

Hello all,
my heater does not seem to flow as much air as I feel (or I think) it should.

When the heater turns on, you can hear that it is working, flame on, blower on etc., but the only floor register that really flows any air is the one in the bedroom floor, ("north" of, and closest to the heater, 2-3 feet away from the heater),
which is located under the stairs into the bedroom.

The next register in line, is at the bottom of the stairs.
("south" of, and again, only 2-3 feet away from the heater unit). This is at the "north end" of the kitchen island.
This register flows significantly less (very little) warm air than the bedroom register.

The next 2 registers are located, (1 at the "south end" of the kitchen island, i.e. the beginning "north end" of the living room, and the last register is at the
"south end" of the living room, i.e. rear of the trailer (and furthest away from the heater unit.
These last 2 registers flow almost zero air, and you literally have to put your hand on the register, to feel even the slightest bit on warmth . Basically no airflow at all.

Is this a common problem ?

When the heater is running, and I go outside to the external heater vent, there is a lot of airflow, and it seems that more heat is being exhausted from the firebox, than is going inside to heat the interior of the trailer.

My rig does have the "Arctic" package ,with the insulated and sealed flooring under the rig, so I cant really see any of the heater ducting that goes to each vent/register.

FWIW,
my rig is an '07 Montana 3600RE. 38 feet long.
It has been towed less than 100 miles since it was new,... so it's not like it has seen any rough roads, excessive vibration, or abuse at all.

I am the 3rd owner.
I purchased it last November, and I live in it full time in a 55+ RV park in Mesa, AZ.

The original owner, as well as the 2nd owner, were "Snow-birds", and only used it approx. 4-5 months per year, during the winters.
When they were not living in it, the rig was always fully covered and maintained.

Thank you for any help, suggestions, and replies.
Cheers,
Ron

[AZ Traveler]

Get into the basement and check that the ductwork to the registers is hooked up.

[Daryles]

As AZ traveler mentioned you will need to take down your basement walls and check the air ducts to verify they have not become detached. You should find 1 duct that hangs down. This should be pointed towards your tanks and waste valves to keep them from freezing in the winter.
Also get an endoscope and go up the vent duct work of the floor vents to be sure there is no obstructions there.
https://www.amazon.com/Compatible-NI...dDbGljaz10cnVl

[DadsHemi]

Your propane heater is not a ducted return like your home, it’s pulling the return from the basement as a plenum return pluse heating underbelly of your 5th to keep things from freezing. Also when you use the propane heat your floor will be warmer. Ours does an exceptional job and we’re getting down in the very low 20s at night.

[DutchmenSport]

Unfortunately, a GREAT amount of your propane furnace heat is probably blowing under the floor to keep your pipes and such from freezing. I figure in mine, probably 1/3 of the heat goes under the floor. It took 2 years for me to accept that fact. And it's not uncommon to go through a 30 pound tank of propane in 2 days if the temps are below 15-20 and I'm not supplementing with electric heat because so much is going "down under."

My guess is, yours is too.

You can remove the back wall in the basement of your camper and gain access to everything under the upper level. Now, getting back there to do anything is another matter! Unfortunately, to see anything farther back, you have to remove the underbelly covering.

Something simple you can do though. Just crawl under the camper and touch your bare hand to the underbelly. If it feels warm, you know a great amount of your heat is going "down under". It might be by design, or a duct may have come loose. But doing so, you'll be able to tell pretty fast how much heat is going 'down under" and not inside the living part of your coach.

Good luck.

[Gertrude]

Thanks for all the replies so far.
I will pull the basement wall and report back my findings.
I HOPE that it is not a case of intentional design to put some of the heat "down under ".
Bit if it is, and since I am in Az., and it wont be seeing anything below about 45 degrees, I will look at the possibility (maybe ?) Of redirecting that to the ducting

[STIHLNTIME]

AZ can get cold. Stayed at Wickenburg an hour northwest of Phoenix during Nov, Dec and seen several nights get in the lower 30’s. Use one 30 lbs tank of propane a week.

[Gertrude]

At first I did notice the propane consumption to be pretty high, but I had the thermostat at 65-67.

I work night shift now, and quickly decided that it does not need to be warm while I'm at work.
I get home from work at 1:30 am.

So now, I **** the thermo down to 50 before leaving for work, and only bring it up to 65 when I get home.
A small electric space heater in the bedroom and another in the living room brings the temp to comfortable in about 10 min

[Gertrude]

Originally Posted by STIHLNTIME

AZ can get cold. Stayed at Wickenburg an hour northwest of Phoenix during Nov, Dec and seen several nights get in the lower 30’s. Use one 30 lbs tank of propane a week.

Yeah, Wickenburg is about 1000' higher in elevation than Mesa, so you can figure 15-20 degrees colder than Mesa.

[jimcol]

I posted on these concerns several years ago but the search function didn't find it. I had your same concerns with heating air flow when my unit was new. I'll attempt to summarize. Our units are close in age so probably ducted somewhat in the same manner. On mine the only two flexible ducts are in the underbelly. One dumps into the underbelly to keep pipes from freezing the other is attached to the floor vent in the toilet closet. As other suggested this is easy to see from the basement by removing the back wall panel of the storage area. Then there are two pan ducts off the plenum. They both supply your floor registers. One goes towards the front to heat the upper bedroom level the other duct feeds the floor registers on the lower level. My two bedroom registers seem to move more air as it is a shorter run with only two floor registers. The service manager explained the ducting on the lower level. In the duct run right before the first register from the furnace there is a baffle in that run. It's purpose is to divert most of that forced air around that first register. This insures ample air is supplied to the remaining floor registers in that run. Without the baffle most heated air will go out the first register (also closet to the thermostat on my unit) leaving the back of the unit less warm. Needless to say I didn't believe him but removing the floor registers, shining a light placed in the ducts last register shining towards the furnace, and standing on my head at the first register opening looking towards the furnace with a mirror I could see the baffle. It is really no more than a strip of sheet metal standing on edge and curved to divert some of the air supplied. Working as designed. The service manager made some pretty wise comments that have served us well while RV'ing in some pretty cold weather over the last 14 years.
1. These are not high efficiency furnaces like you place in your home. Stand outside next to your exhaust port. Lots of the furnace heat goes out the exhaust.
2. You will never feel forced air from your registers like you do in your home where most registers have a 6" duct coming off a 24"X12" main duct run moved by a pretty big blower. These are RV'S with lots of space constraints, not stationary homes.
3. "Are you comfortable in your unit when the furnace is running?" Quit worrying about what you feel out of the registers as long as the system heats the unit in the manner as it's designed to.
4. When temps are above freezing utilize other heat sources like the fireplace or electric heaters.
I'm sure I probably stated things better in my original post when the issue was more current in my mind but I hope this gives some clarity to the issue. Good luck and enjoy your RV.

[Dave W]

I installed adjustable heat registers (Lowe's) in some of the floor vents to force heat to the far end of the LR and BR. There were two vents, bathroom and bed room within a couple feet. The bath room which is directly above the furnace has one and the floor vent at the entry door end at the end of the counter has another. In doing this, heat now keeps us warm in the BR and the back of the 5ers LR. These vents are listed as 'mobile home' registers and are about 10 bucks each. As far as heat to the basement - we don't do cold weather camping since there are no CGs open anywhere within reasonable driving distance, Nov - April.

[jcurtis934]

You might also check that very last floor vent in your furnace run. In my trailer built in 2012, I found that the floor duct after that last vent was not sealed off at its end and I was also pumping heat into the very rear of the underbelly. Was this keystonesvway of getting some heat to the fresh water tank or crappy assembly line work I do not know. Since I never put water in that tank, I used some fire retardant spray foam to seal off that opening. Easy to remove with a stick should I want to have heat in the underbelly.

[beeje]

The only time we use the on board furnace is to quickly heat up the unit if we are camping when its cold. As soon as it heats up, we use a ceramic heater or 2 to keep it warm. The propane heater will empty your pocket fast.

[Reelfoot]

I had the same problem. Only about 30% of the CFM at each floor outlet that I should have had. Turned this in as a warranty item but dealer said everything was okay, no problem. The next heating season I cut a few openings in the under belly of my 2018 HC 305rl to find the 4” flex duct mashed between the top of the floor joist and floor. The factory had installed the 4” duct in a 2” opening. Needless to say in every location the duct crossed the steel joist the flex duct was cut in half, about six locations. It took me about two days but I replaced all the 4” flex duct by properly routing it in the openings in the steel floor joist. I will bet many, many units had the duct work installed just like mine. Probably still doing it because it is faster —- if Montana has quality control I bet his name is Sleepy.