Keep OTR Heat or Not

[bevans6]

My take is that if you have any plans to actually drive the bus any significant distances with the outside temp below around 40 degrees, the only way to heat it is with the OTR heat.  If you have any plans to have a working defroster, you need to keep the OTR heat.  AC is another story, you can run sufficient AC to keep the bus livable with a generator, but you can't realistically generate enough heat with the cold air in-flow while driving.  I control mine by turning it on and off, the thermostatic control does not work. 

[richard5933]

One of the things I have seen multiple times on the various bus conversion sites is new owners jumping into the process of gutting their bus, only to find out later on that they've removed and/or discarded things they shouldn't have.

For anyone out there reading this thread while dreaming of their first bus conversion project, make a mental note to think through the HVAC systems thoroughly before tearing out various components.

The OTR heat is the best and easiest way to stay warm while driving, in my opinion. There are ways to modify the system to work with furniture, cabinetry, etc. But, having the core components of the system in place is often helpful. On our 4106, there were a few places where Custom Coach removed the OEM ducting, but they re-routed into the ceiling of the bay below it. This allowed placement of cabinetry against the wall, and also allowed heat to be directed into the wet bay while driving. Similar on our current coach - the ducting has 'extensions' connected in a few places to bring the heat and a/c flow around cabinetry. Works like a charm.

[neoneddy]

Here is how I did my heat. https://www.youtube.com/watch?v=jvIlipRhiwA

I recently installed a propane heater using the OTR ducting.  I'm up here in MN and it can get cold even in fall, I love the OTR heat.   I took out the main ducting inside, but left the vents in place.  I then sort of made my own ducting in the walls.  I use 2x3 on the 1.5" edge and insulated then covered over the walls, leaving about 8" x1.5" 40" long duct of sorts to run the length of the bus.   Then I just cut holes in it where ever I want heat.  It works for OTR system as well  as the Propane system.

[Jcparmley]

That sounds like what I will need to do for my duct.  Would you by any chance have any pics of the duct you made?  I am trying to invision it but I am having trouble.

Here is how I did my heat. https://www.youtube.com/watch?v=jvIlipRhiwA

I recently installed a propane heater using the OTR ducting.  I'm up here in MN and it can get cold even in fall, I love the OTR heat.   I took out the main ducting inside, but left the vents in place.  I then sort of made my own ducting in the walls.  I use 2x3 on the 1.5" edge and insulated then covered over the walls, leaving about 8" x1.5" 40" long duct of sorts to run the length of the bus.   Then I just cut holes in it where ever I want heat.  It works for OTR system as well  as the Propane system.

[neoneddy]

It's all covered up now, here is what I could find, plus a high quality architectural drawing.

[chessie4905]

Yank that Cat and put in a 550 hp 8-92. You'll have plenty of heat.lol

[sledhead]

oh but would the 8v92 give me 1875 lbs of torque ?

thanks buswarrior about the heat on the Cat that makes a lot of sense now . I have been shaking my head thinking the builder of the coach did a amazing job on most things and though they made a mistake with the otr heat as there is only a 3/4 " heat line that comes from the engine to the aqua hot system and return . the driver heat is separate and has lots of heat up front . I installed a thermostat for the aqua hot system that controls the heat in the coach right at the drivers seat

dave   

[Jim Blackwood]

I'm watching all of this like a hawk, since I don't even know what the ductwork on a D series looks like. All I really know is that it has overhead vents for the A/C. Is the same system used for the heat but with the flow just reversed or something? That would seem to make sense as cold drops and heat rises. Or is it something more complicated? I remember you guys talking about how the A/C is moderated by using the heat. I'm guessing it doesn't work the other way since you can't cycle the compressor.

So do you have a lower duct and an upper duct then? And I suppose these are duplicated on both sides? I can see the lower ducts being interrupted by the refrigerator and the shower but can't really think of anything that would have to interrupt the upper ducts. Obviously the cabinets would have to be trimmed to fit over them. Does that sound right? And I suppose it sounds like you could maybe run the lower duct through the bay where it has to be interrupted. I think I could handle that without too much trouble. What is the usual solution, drop a panel a couple inches below the top of the bay to create a plenum there? Plywood maybe?

Still watching for the right bus, hope to have something by spring.

Jim

[neoneddy]

Mine run the length of the bus including behind the fridge and shower. 

I'm thinking about adding small 12v fans to sort of suck the air from the ducts in the back and act as a bit of zone control. 

[Jim Blackwood]

Cool! How big are these ducts?

Jim

[jraynor]

Cool! How big are these ducts?

Jim

I can't speak for a d series but for my a series, it has about a 4"*8" duct at the floor. Both heat and AC run though this vent and is fed by the fans just forward of the 1st Bay. As for the ceiling vents, the only ones I had were in the luggage rack (parcel rack as they call them). This was really just a squirrel cage fan blowing ambient air down a narrow channel for each Rider to catch a part of. All of that has been removed. So D's may have something else but I'm not sure. You can look at all of the manuals for a d series and up at MCIs website and can see how they built them factory

[TomC]

Yes an 8V-92TA will give you plenty of heat, and the 8V-92TA was the hardest engine to cool too-meaning it looses alot of it's efficiency through wasted heat. My 3406B Caterpillar in my truck provided plenty of heat in the winter-including in -10 degree at night with the engine on fast idle all night long. Good Luck, TomC

[Jcparmley]

Jraynor, do you still have that ducting? 

What year/model is your bus? My OTR AC still works and I kept the duct, but I probably wont be using it. I have other plans for a duct system, just not 100% sure what it is yet. I actually have all the parts do the duct, including the rear ramp where the return starts

[jraynor]

Jraynor, do you still have that ducting?

I actually sold them about 2 months ago. Shipped them out west