Still no working furnace in my brand new coach after 10 months!

[TimmyB]

Originally Posted by YC1

What works on paper and what works in reality are often two different things. I have seen these things run at a much lower voltage.

Just been at this kind of thing for tooo long. I would bet just about everyones' furnace has around a 1 volt drop in wiring. Too costly to run huge cables and heavy of course. Every ounce counts.

Just my humble opinion and experience.

Originally Posted by HVAC ZACH

Tim, we use Air Velometers. or air data meters. This gives us a close to accurate calculation of how much air is coming out of the vents. Then add all of the vents air flow calculations up and that is total air flow. If i remember the instructions recommend to set the ducts up on discharge air temp by adjusting them for a discharge temp of 105-125F. at a .1 static pressure. The static is very common for all installations but normally we set duct work up for air flow. each duct size flows a given amount of cfm. For examp. a 6" round duct at .1inwc static will carry around 120cfm. so your little furnace has a smaller fan but the principle is the same. You use smaller duct and fewer runs the only difference is velocity is usually less. Anyway I guess what I am trying to say is since you opened the end of your plenum that was already opened once before you should have moved enough air to not trip the unit on high temp. What is the size of that opening that is taped up Tim? just wondering...

Myron, Zach:

I called Dometic today, just to see what they might say about our findings, so far. The technician was (in his words) 99.9% sure that it is a blockage issue, based on his experience with this. While he agreed that the limit switch should be replaced due to it tripping this many times, he also agreed that it appears to be doing its job properly as the temperature of the air is getting up to 200 degrees. The limit will kill when it reaches 190 at that switch, so if it were being weakened significantly, the burner would have turned off long before then.

I have ordered a bore scope, as you suggested, Myron. Unfortunately, it won't be here for a week.

Also, I found the fifth duct, hiding in plain sight. There is a register in the hallway, on the wall directly across from the refrigerator. Since we are never standing there for very long, I just never noticed it. So, all five ducts are now accounted for: under bed, hallway, bathroom, living room, and water control bay.

[TimmyB]

The borescope arrived today, but unfortunately, I can't get it snaked through the duct to check how clear it is or isn't. There are too many twists and turns and the scope simply snags on the ribs of the duct. I even tried taping it to a fish tape and pushing it through but had no success. Any tricks to this or am I trying to do something that this scope just isn't capable of doing?

[YC1]

When in doubt, tear it out.

[TimmyB]

Originally Posted by YC1

When in doubt, tear it out.

But I can't tear out duct work and that's what I'm trying to check. 😢

[RRR]

Originally Posted by TimmyB

The borescope arrived today, but unfortunately, I can't get it snaked through the duct to check how clear it is or isn't. There are too many twists and turns and the scope simply snags on the ribs of the duct. I even tried taping it to a fish tape and pushing it through but had no success. Any tricks to this or am I trying to do something that this scope just isn't capable of doing?

Could you drill a small rubber ball and push the scope into it? Maybe something smooth would let it pass over the ribs of the duct.

[TimmyB]

Originally Posted by RRR

Could you drill a small rubber ball and push the scope into it? Maybe something smooth would let it pass over the ribs of the duct.

Yes, we thought about that but were unable to find anything lying around. Going to search further today.

Thanks!

[US1]

If both ends of the ducts are accessible, use a leaf blower at the register end while an assistant is at the furnace end of the duct. Should get a good feel for airflow, or at least an obvious blockage if lack of airflow.

[TimmyB]

Originally Posted by US1

If both ends of the ducts are accessible, use a leaf blower at the register end while an assistant is at the furnace end of the duct. Should get a good feel for airflow, or at least an obvious blockage if lack of airflow.

No, sadly they are not. Two of the ducts come out of the bottom of the furnace where there is no access whatsoever. I'd have to remove the furnace, which is what I'm trying to avoid at this moment.

Thanks for the suggestion! It is a great idea, if I can get to those ducts.

[AZ RV'r]

Do you have a vent like this under your refrigerator?

Have you removed the screws and looked in it?

I have a metal junction box with heater hoses running out to the vents.

Just a thought. Good Luck!

(click picture to enlarge)

[TimmyB]

Originally Posted by AZ RV'r

Do you have a vent like this under your refrigerator?

Have you removed the screws and looked in it?

I have a metal junction box with heater hoses running out to the vents.

Just a thought. Good Luck!

(click picture to enlarge)

No, our fridge goes floor to ceiling. The two vents that are giving me problems are the ones in the hallway (directly across from the refrigerator) and under the bed. They both take a big turn about 18" in and I'm having problems getting around those corners. Both of them run under the floor, so there's no way to see what's happening from the outside of them.

Thanks!

[YC1]

Originally Posted by TimmyB

But I can't tear out duct work and that's what I'm trying to check. 😢

I meant to tear/take out the furnace. Someone is going to have to do it to fix it.

[AZ RV'r]

Originally Posted by TimmyB

No, our fridge goes floor to ceiling. The two vents that are giving me problems are the ones in the hallway (directly across from the refrigerator) and under the bed. They both take a big turn about 18" in and I'm having problems getting around those corners. Both of them run under the floor, so there's no way to see what's happening from the outside of them.

Thanks!

Do you have a wood vent like the picture I posted above anywhere on the inside? I just went to the Fleetwood website and to the Bounder page and in the stock pictures they show one under the oven.

The reason I bring all this up is your coach and mine are only one year apart and I have to believe have several similarities.

I have two furnaces both on the door side of my coach... One near the middle and one at the very rear corner. Im assuming you have just one. My 2016 Bounder had one and was the same length as yours.

All of my heating duct work seems to be run on my door side of my coach and nothing goes across to the drivers side that I know of. I have mentioned above that I have this silver, metal, junction box with the flexible hoses running out of it and then off to the separate vents... I have to believe you have one too. Maybe it's just hidden. If you are able I would begin searching directly inside, the exact spot where your furnace is installed on the outside. If you can I would begin with extending your kitchen drawers all the way out and looking with a flashlight or if easier just removing the largest drawer completely and sticking your head in there to look around. To me it makes sense that you also have this box, because the heat from your furnace has to spit to the individual vents somewhere, and it would make sense to be VERY close to that location.

I don't know how I can help.... but I can FaceTime (if you have an iPhone) and run mine for you to see how it operates, or send you pictures of my stuff if you think of anyway that it would be helpful. Im home all day, and my coach is garage stored on my property.

So many pages of helpful tips... we should have figured this out by now there are many knowledgeable people contributing.

Good luck

[TimmyB]

Originally Posted by AZ RV'r

Do you have a wood vent like the picture I posted above anywhere on the inside? I just went to the Fleetwood website and to the Bounder page and in the stock pictures they show one under the oven.

The reason I bring all this up is your coach and mine are only one year apart and I have to believe have several similarities.

I have two furnaces both on the door side of my coach... One near the middle and one at the very rear corner. Im assuming you have just one. My 2016 Bounder had one and was the same length as yours.

All of my heating duct work seems to be run on my door side of my coach and nothing goes across to the drivers side that I know of. I have mentioned above that I have this silver, metal, junction box with the flexible hoses running out of it and then off to the separate vents... I have to believe you have one too. Maybe it's just hidden. If you are able I would begin searching directly inside, the exact spot where your furnace is installed on the outside. If you can I would begin with extending your kitchen drawers all the way out and looking with a flashlight or if easier just removing the largest drawer completely and sticking your head in there to look around. To me it makes sense that you also have this box, because the heat from your furnace has to spit to the individual vents somewhere, and it would make sense to be VERY close to that location.

I don't know how I can help.... but I can FaceTime (if you have an iPhone) and run mine for you to see how it operates, or send you pictures of my stuff if you think of anyway that it would be helpful. Im home all day, and my coach is garage stored on my property.

So many pages of helpful tips... we should have figured this out by now there are many knowledgeable people contributing.

Good luck

Sounds like we are the complete opposite. Our furnace is driver's side, under the electric fireplace, which is under the LR television. The furnace is vertically mounted (exterior driver's side access) with three ducts coming out the back (easy access) and two coming out of the bottom (REALLY difficult access). The three go to Living Room (two feet of duct), under shower (four feet), and either the bedroom or hallway (impossible to tell, under floor). The two bottom ducts go to the bedroom or hallway AND the water bay, which is just an open duct right above the water control panel.

After talking to Dometic this week (second time), the technician was 99.9% convinced it's an airflow problem, so that's why I was trying to either confirm or eliminate that as a suspect.

Thanks for your offer to help. Not sure which way I'm going to proceed, as of yet. At worst, I'll do nothing and let REV have it for the third time. The last thing I want to do is mess this thing up and have REV give me a bunch of flack for "breaking" it.

[Hittntheroad]

I have read all the pages of recommendations to try. Did you try bypassing the thermostat by applying 12 volts to the white wire to the furnace?