Heat ducting

[okiejoe]

I have a Thor Chateau 31W, it has the full length slideout on the drivers side, my problem is that the duct work under the sink that goes under floor over to the other side to the bathroom and living room has very little air coming out but loads of air coming out of flexible duct under sink if I pull it out. Any thoughts?

[navegator]

My C came with a rear galley and head, the heating duct for the galley was a 3" and the one for the head a 2" so I rerouted the 2" to the galley and the 3" to the head I had to add more 3" duct, in order to have more air flow I installed a spark proof blower for the 3" duct to the head, these are used in boats to vent the engine compartments and installed a switch in the head for the blower motor, at the same time I installed a switch in line with the water pump switch.

navegator

[whizbang]

The other thing is the flexible duct is probably too long.

We had the same low air flow problem with our Class C. The duct on the longer runs were cut about 18 inches too long. So, the factory folks just left a lazy "U" shape in the middle of the duct.

I cut out the extra length and straightened the duct and the air flow increased.

[okiejoe]

Well the duct work iand furnace are under the kitchen sink and to heat the bath room it one of the ducts goes under the floor across and then back up under the fridge then through a wall into bathroom so I’m beginning to think there are too many 90 degree turns causing restrictions. I think I’ll get a camer to rn through to see if there may be an obstruction

[wildtoad]

Where is your furnace in relation to the ducts? I suspect it is closer to the vents that have a lot of air flow, and not so close to the ones that have minimal flow. Air will flow towards the closer ducts.

[donn0128]

For less than 25 dollars you can buy a flexible camera that will work with your smart phone. Get one and start looking.

[azrving]

Remove any grills and even look at the furnace area for deteriorated foil tape. When working on my ac years ago I found that most of the tape was deteriorated and cool air was blowing into the roof cavity.

Recently I removed the duct elbow between the furnace and the floor sheet metal. It had a large gap that was blowing into the floor cavity and the tape was bad. Mine also has separate hose ducts besides the metal floor duct.

The tape doesn't last forever but the general application and missed gaps was pathetic.