3210 furnace ducts

bcpolaris

bcpolaris
Where would I look for the blockage in the furnace ducts. There is very little air coming into the bedroom air duct and the bathroom air duct. The two in the kitchen have a little more airflow but nothing to write home about. I did take off the front panel and the furnace is working fine as is the blower.
 

noconwud

Member
furnace efficency

We have a 3210 purchased 2 months ago. We have same problem. Also is VERY loud!! I am looking into the whole system and am finding a lot of problems! First, take the end cap off the furnace itself-it is the panel you see behind the return air grill. The cut out in the bottom of the furnace thru the floor to connect to the under floor duct is not right. It is making the air flow over the heating bonnets restricted and inefficient and is causing poor flow and to much back pressure. It needs to be DUCTED from the end of the furnace housing (knock-outs provided) thru the floor and into the duct. Also, behind the access panels in the front storage comp. you will see 2 flex ducts that go to the bedroom and bathroom vents. Disconnect these hoses and where they connect to the main duct you will probably see that the cut out in the floor is not big enough for both hoses. On mine, the bedroom duct had less than a third of the hole cut out!! No wonder there was hardly any air coming out of that vent!:mad: I am going to retrofit this with a larger plenum and duct off of that. I am also going to add another vent on the other side of the bed.
The furnace has the capacity, but the ducting is very inefficient and not enough vents are being used. Good luck:rolleyes:
 

StevieWonder

Well-known member
Had essentially the same problem with a 2008 Sundance 2800RLS.

The ducting was improperly routed near the front of the trailer and was getting just residual airflow while forcing the air mostly out of the living area floor vents. The blew a gale while it was a whisper out of the bedroom vent (lowly Sundance owners don't have a bathroom vent). Took it to the dealer and they fixed it.

Apparently a way too common issue. More than a few threads here on this exact same topic. One of the few weak points in the Heartland build process.
 

bcpolaris

bcpolaris
noconwud thanks for the insight. Could you please take a picture of the furnace area in your unit and send it to me.
 

Dirt1st

Member
I also had a problem with the delivery of hot air through the various registers. Examining the heating system found several problems. First problem was that the hole cut in the floor beneath the furnace was in the wrong place. it did not match the hot air discharge from the furnace by about two inches. Most of the furnace discharge was circulating within the furnace cabinet. When I removed the return air cover, I could look down into the ducting through a hole about 2 inches wide and the width of the furnace. Next problem, I removed the floor registers and used a small mirror to look at the duct work. There were large gaps around the bottom edges of the holes cut in the floor and the top of the hole cut in the metal ducts, with more of the hot air going in to the space underneath the floor of the trailer. I solved that problem with silicon seal and sheet metal screws, fastening the edges of the holes cut into the ducting to the bottom side of the floor underlayment. Third problem - in looking inside the ducting with a light an mirror I found two instance where the duct had apparently been forced into the space between the floor joists, and had buckled and split at the corners. Some of the openings could be sealed with silicon, some of them required use of metallic duct sealing tape.
If your are experiencing low air flow I suggest you remove the floor registers and the return air register and take a good look inside the ducting.
 

davelinde

Well-known member
Had essentially the same problem with a 2008 Sundance 2800RLS.

Apparently a way too common issue. More than a few threads here on this exact same topic. One of the few weak points in the Heartland build process.

crud. Just took delivery of a 3210 and it was 90+ I did turn on the furnace to make sure it would kick on... and everyone started shouting at me :) so I never really checked airflow.

So OK - we DO NOT like to be cold and we will have two sleeping in the front, one in the bunk and one in the garage - will all get some heat - or should I be looking into alternate heating for the back and re-working my duct to the front? What about a quick warm-up for breakfast? We do not camp in the cold if we can drive away from it... but sometimes we are stuck and cranking the heat is one of the last RV'ing luxuries I can afford!!!!

To anyone who has corrected this... PICTURES Please -- I'll "get it" a lot faster then.
 
Had the same problem with my 09 3210. I found two fairly large holes cut into the bottom of the heating duct running in the floor feeding the register just inside the front door and the one just in front of the oven. They use these two holes to feed hot air to the fresh water tank and the black holding tank valve. I removed the two registers, used a flashlight and mirror to see the holes. I was able to use some foil tape to cover the holes and now have fantastic airflow at all registers including the bedroom and bath.

I have also removed the belly plastic from the bottom of the trailer and can actually see the hole that was feeding hot air to the black tank valve. I have also removed the fresh water tank and can now see the hole (that I have taped over) as well.

As for the excessive furnace noise, I just placed a piece of plywood inside the inlet plenum (under the fridge) to create a baffle. Works great and cuts the noise way down so we can still hear the tv when the furnace comes on.

Hope this helps.
 

RIOF16

Member
I just ordered a 3210 a few days ago. Am I going to need to immediately begin dismantling and rebuilding my ductwork on a new unit right from the factory when I pick it up in about 3 weeks? Should I take it apart and inspect it before I accept it?

RIO
 
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Dirt1st

Member
RIOF16, I would not accept delivery of the trailer without a thorough inspection of the heating system. Remove the return air register (beneath the fridge) and inspect the furnace plenum box, making sure that all of the round metal plugs used to block off the side air ports on the plenum are in place and tight. On my trailer, they were all very loose, and one was laying on the floor, dumping hot air into the space beneathe the fridge. I removed all of the plugs, layed a bead of high temperature silicone seal around the edge, and reinstalled them.
I would then remove all of the floor registers and, using a mirror and flashlight examine the duct work for splits in the corners. Also look closely at the edges of the holes cut in the floor of the trailer to see how well the edges of the holes in the duct work match up and seal.
We just returned from a two week trip to Oregon. All but one morning the outside temperature was in the low 30s. My wife and I sleep with the thermostat set down to about 55 at night - the furnace was adequate to get the temperature in the living spaces up to a comfortable level in about 15 minutes.
 

RIOF16

Member
Dirt, thanks my friend.

My only question is already obvious:
When they build these trailers, why don't they get ALL the BASICS right, like ductwork? (For those inclined, don't rage on me, just relax. I've been under more than one 90 year-old house wading through cobwebs installing a totally new HVAC system.)

I won't be upset if in a few years I have to buy parts and do repairs, but what if I have to preform [I know, it's a satiristic joke] repairs before I even get to spend one night in it?

For anyone about to defend the company, relax, I'm already a huge Heartland fan. Please, don't point out all the things that they do right. I wouldn't have ordered one if I didn't like what they're doing. What I'm saying, is, if you get on my 737 and I say:
"Folks, welcome aboard... I am the worlds greatest pilot, but I just ain't that good at landing."

What will your next action be?
-RIO

P.S.,
so....am I still going to have to fix the HVAC system soon as I take delivery? I will only be 50% as disappointed if you just tell me the truth upfront before I have to find out by being too hot or too cold. That way, I just pay forty eight grand plus a couple hundred at lowe's ahead of time, and everybody's happy. My TIME is what I value most.
 

Dirt1st

Member
3210 Furnace Problems

I didn't have any blockage in any of the ducts that I could see. The problem I found was that most of the hot air the furnace was putting out was leaking out of the ducts and going into the space beneath the floor. Some of the leaks were the result of splits in the seams of the duct work, mostly at the corners. I think the ducting is installed after the floor is layed down - the frame with the flooring is turned upside down, and the ducting (with no openings for the floor registers) is installed. The frame is then turned rightside up, and holes are cut in the floor (and the duct work beneath the floor) for the registers. In my trailer, cutting the holes in the floor forced the thin, metal duct down, leaving a gap between the bottom of the floor material and the top of the duct. I used silicone seal and sheet metal screws to fasten the edge of the hole in the duct to the hole in the floor. If the actual furnace installation looks OK, and you really need to have the furnace blower going when you check so you can feel for any air leaks, then you should remove all of the floor registers and examine the inside of the ducts with a mirror and flashlight for gaps and splits, paying particular attention to the edges of the holes cut in the floor and the ducting.
My personal opinion is that the furnace installed in the 3210 is barely adequate, size-wise, for the size of the trailer when used in even a mild climate. The method used to install the furnace and ducting allows for the creation of a lot of air leaks beneath the floor thereby reducing the ability of the barely adequate furnce to provide hot air to the living spaces.
 

davelinde

Well-known member
This weekend was our first camping where heat was needed... and we didn't get it :( so per this thread I think I will need to start to pull apart the ducting and patch holes to start. The bedroom was getting essentially zero airflow.

We also had an odd experience. This morning we cranked the heat all they way up to try to warm the RV for breakfast so it ran a while. We smelled something odd (maybe burnt plastic?) and the smoke detector went off. When the unit was running on a shorter cycle I smelled the smell and guessed it was some "normal" thing burning off the brand new system. When the smoke detector went though I got to wondering.

I'll be pulling the system apart due to the airflow problem - any idea what to check for abnormal melting?
 

bigredtruck

Well-known member
crud. Just took delivery of a 3210 and it was 90+ I did turn on the furnace to make sure it would kick on... and everyone started shouting at me :) so I never really checked airflow.

So OK - we DO NOT like to be cold and we will have two sleeping in the front, one in the bunk and one in the garage - will all get some heat - or should I be looking into alternate heating for the back and re-working my duct to the front? What about a quick warm-up for breakfast? We do not camp in the cold if we can drive away from it... but sometimes we are stuck and cranking the heat is one of the last RV'ing luxuries I can afford!!!!

To anyone who has corrected this... PICTURES Please -- I'll "get it" a lot faster then.

There is no heat duct to the garage and no insulation in the floor, so Dh is under the trailer right now insulating the whole thing and cutting a whole in the rear wall to duct the furnace in there. We also have alittle one sleeping in the garage and it was pretty cold in the mountains last weekend.
 

davelinde

Well-known member
...The cut out in the bottom of the furnace thru the floor to connect to the under floor duct is not right. ...It needs to be DUCTED from the end of the furnace housing (knock-outs provided) thru the floor and into the duct. Also, behind the access panels in the front storage comp...the bedroom duct had less than a third of the hole cut out!!... I am going to retrofit

This morning got a little chilly again and (as usual) the kichen got toasty warm fast while the rest of the RV wasn't getting airflow. That was enough motivation to go looking at the ducting under the fridge. Now that I've seen it I understand better. (I have not crawled int the storage yet to look at that).

Have you done any of these mods yet? How did they work out? Re-ducting the furnace itself looks pretty involved and I'm not convinced I see the benefits. If the front vent feeds are pinched that will be a help for sure.

At this point I'm leaning more towards putting vents in the kitchen that can be shut off to direct more air to the bed/bath (where I WANT it early in the morning).

Pondering now.
 
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