Furnace not sending heat to front of 5W - Is it broken?

[tommygun714]

Hi,

First time out with new 5th wheel. We ran the heater and did not get any heat to run to the front of cabin, bedroom and bathroom. This is a new cougar 5th wheel. It has ducted heating and two thermostats.

We have a second air conditioner on the bedroom but event though there is a heat option on it no heat would every turn of from that controller. Thinking it was just for the front Air Conditioner. What is the typical way the air goes to the front? Is it a damper system? And how or where might I control the diversion of the air flow to the front?

[ksbowman]

I just noticed a lack of heat to the two registers in the bath and bedroom above in our Keystone Outback. I got underneath the upper duct by removing a panel in the basement and the flex tube connecting the lower and upper duct had become disconnected. The flex duct had only been taped to the rectangular metal duct. I zip tied it back, then retaped with duct tape. Good air flow and good heat to the upper level of the 5th wheel.

[austinjenna]

My one pipe was crushed as well that we noticed during the PDI

[laknox]

tommygun714 wrote:
Hi,

First time out with new 5th wheel. We ran the heater and did not get any heat to run to the front of cabin, bedroom and bathroom. This is a new cougar 5th wheel. It has ducted heating and two thermostats.

We have a second air conditioner on the bedroom but event though there is a heat option on it no heat would every turn of from that controller. Thinking it was just for the front Air Conditioner. What is the typical way the air goes to the front? Is it a damper system? And how or where might I control the diversion of the air flow to the front?

Main causes of air restrictions:

1) crushed/kinked ducts
2) poorly installed or completely non-installed ducts
3) construction trash blocking the ducts
4) extremely poor duct design
5) some combo of all 4

This is a new unit, under warranty. Take it back to the dealer for correction or, if that's really inconvenient, call the factory and ask if they will authorize warranty repairs by a mobile tech. Upside to a mobile tech is that you can actually watch what they do and learn how to DIY.

Lyle

[time2roll]

lee worsdell wrote:
My main duct called the plenum was crushed and my trailer was brand new.

Same on mine. Very restricted air flow so bad it would cycle with the high limit switch. Basically the firebox was over heating.

No real access to replace the ducting. Propped it open a bit shoving some aluminum into a key area. The real solution was to add two additional 4" ducts. Tons of heat now.

[1Wheeldrive]

It could be a simple fix or it could be a major job, speaking from experience. Before returning to the dealer, you can make a quick check with a flashlight and a small mirror. Remove each register and using the mirror and a flashlight look at the ducting to see if there are any obvious disconnects. If you see a problem, you can decide if you want to try to fix it your self, or return to the dealer.
My experience a couple of years ago with a new Cyclone toy hauler was that there was very little heat coming from the registers, but the furnace was working. I pulled the return air flow register and found that the hole in the bottom of the furnace plenum did not match the hole cut in the floor to access the heater ducting, and the warm air from the heater was just recirculating in the cabinet where the heater was located. The solution was to remove the heater, cut a new hole in the floor to match the hole in the heater plenum and cover the original hole in the floor. I did this myself because I did not trust the dealer to fix the problem, based on previous experience.

[pcm1959]

I agree with others. Its probably a simple fix and if at all handy, you can fix it yourself and save the headache of taking it back to the dealer.
First off, if 2 air conditioners and 2 thermostats its highly unlikely that the one in the upper level has anything to do with the gas furnace. If it has a heat choice on it, its most likely to control the heat pump option (if equipped) on the front a/c unit. If you do not have a heat pump option, then the heat setting on that thermostat is inop.
The thermostat in the main room should control only the main level roof unit and furnace.
Finally, the heat flow to the upper level on fivers is generally always pretty poor but you should get some flow.
Like other have said, its likely a crushed or loose duct OR the duct is disconnected at the furnace.
I think it will be a simple fix.

[lee_worsdell]

My main duct called the plenum was crushed and my trailer was brand new. Took out a few walls in the storage area to get at it. Iam in the hvac industry so we replaced with all metal now. Blows like crazy now

[troubledwaters]

Don't be taking any partitions out, take it back to the dealer, that's what he warranty is for.

[Dayle1]

Usually the rectangular floor duct switches to one or two round pipes in the basement. Likely directly under the stairs. The clamps may be loose and the pipe fallen off. Or there may be something inside the pipe. You will probably have to remove the rear basement wall partition to check the connection.

This assumes you have the propane furnace running. If you are only using the heat strip in the AC, meaning heat is coming from the ceiling vents, then you need to switch the Tstat to get the furnace running.

[FLY_4_FUN]

Im not familiar with your 5er, but having issues at either end of an rv is sadly quite typical. Firstly its possible that the flexible ducting is badly routed or crushed blocking airflow to your bedroom. It is also possible that the system is poorly designed and more air is balanced to the back of the coach. On the 4 rigs I have owned forced air is pushed out vents according to where they sit in the run. Only owner input is to install a register that closes to "balance" heat somewhat while not restricting it too much and shutting down the furnace due to an overheat situation.

I have only ever had one t-stat, so I am unsure how exactly yours is wired. At first glance I would think its solely for the front a/c and not heat but perhaps I am wrong. I just cant see how 2 t-stats can control a single furnace but hopefully others can validate this.

I believe that your first task is to contact your dealer to have them demonstrate how the hvac is supposed to work to confirm that all settings/features of your furnace and A/C are working. If you can show them that no heat comes out a single duct then they should work on it under warranty.

My honest guess is the furnace is barely large enough for the space and ducts are poorly plumbed and front is not getting what it needs.

On edit, looking at outside photos of a similar unit...it appears your furnace is on the curb side just behind the back wheel. This means your bath/mbr ducts are about as far away from the actual furnace as you can get.

Daryll