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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Jcparmley on October 29, 2018, 06:37:05 PM
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I am trying to design my HVAC plan. I am debating if I should remove my OTR Heater by removing the core and gaining that bay space, or keep it. I had considered adding some duct work to the OTR Heater and blowing it outside (basically using it as another radiator) during the hot months or on a long climb. Is this worth it? Or should I remove it, gain the space, and plumb it for in cabin heat like "TomC" has done. THis is a quote of TomC describing his system.
"For bus heat going down the road, I used the heater element from the over the road A/C system I removed. I remounted the element going for and aft at floor level in the hallway under my hanging closet. I have 2-14" 12v radiator fans to push the hot air out. Also have a ball valve to cut off the coolant to the element in summer. Works very well to heat the bus. Good Luck, TomC"
What are your thoughts?
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Both our current bus and our previous one had the OTR heat. We have OTR a/c as well. Wouldn't do it any other way.
If your heat is working, then why mess with it? You've got the best way to heat the bus going down the road, no worries about fabricating something new that won't work as well, and you'll be warm front to back. You'll also have a working defroster and warmth up front for the driver/co-pilot.
To me, have a working OTR heat and a/c is one of the things that gives a bus conversion a huge advantage over a S&S motor home. Why struggle with something makeshift if you've got something that works already.
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I don't think my ac is working correctly so I am most likely going to take that out. When I gutted the bus I threw away the stainless ducts/registers. Now I wish that I hadn't. I see your point about using the heat while driving. I just need to make new ducts. Any suggestions on what would work?
Both our current bus and our previous one had the OTR heat. We have OTR a/c as well. Wouldn't do it any other way.
If your heat is working, then why mess with it? You've got the best way to heat the bus going down the road, no worries about fabricating something new that won't work as well, and you'll be warm front to back. You'll also have a working defroster and warmth up front for the driver/co-pilot.
To me, have a working OTR heat and a/c is one of the things that gives a bus conversion a huge advantage over a S&S motor home. Why struggle with something makeshift if you've got something that works already.
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We totally agree with Richard on keeping the OTR heating & ventilating system. That includes the ducting. We abandoned the A/C portion at purchase of our bus, got a discount & didn't want the independent 4 cyl engine running an 85,000 btu Trane compressor - more maintenance records on it through the years then the bus! The factory heater portion is priceless in cold weather and we used the factory ducting for our recently purchased Atwood Excaliber 2 stage LP furnace when boondocking. Nice thing about the factory dusts is cutting registers in the floor to heat the bottom compartments...
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Unfortunately I removed the original ducting. Perhaps I can make some.
We totally agree with Richard on keeping the OTR heating & ventilating system. That includes the ducting. We abandoned the A/C portion at purchase of our bus, got a discount & didn't want the independent 4 cyl engine running an 85,000 btu Trane compressor - more maintenance records on it through the years then the bus! The factory heater portion is priceless in cold weather and we used the factory ducting for our recently purchased Atwood Excaliber 2 stage LP furnace when boondocking. Nice thing about the factory dusts is cutting registers in the floor to heat the bottom compartments...
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I made my own ducts on top of the floor under the couches I had on each side of the couch .I left the return ducts that go to the back of the coach . tons of heat when you need it . 1/8 " tin foil card board . cheep and easy to work with
on the Featherlite if I don't turn on the aqua heat when its cold and I am driving there is not enough heat ? and that's with a 550 hp engine pushing me ? dumb set up ??
dave
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Unfortunately I removed the original ducting. Perhaps I can make some.
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
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Sledhead, none of the 4 strokes make enough heat, unless there's a load in the coach. ALL of 'EM have a Webasto/Proheat in them to supplement the coach heat. Runs automatically as needed when engine is running, pre-heat is the bonus feature.
Deadhead empty Toronto to Kingston one sunny winter day, a tall H3 45 with a S60 detroit and allison, set cruise at the limit, lots of time to save the boss some fuel, never reached operating temperature in 3 hours... as soon as I loaded the hockey team, their gear and supporters, right up to temp, once we got back on the highway, and "aux heat" light finally went out.
Like your wipers, you only need 'em when you need 'em, but when you need warmth, you REALLY want it.
Happy coaching!
Buswarrior
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Jraynor, don't throw stuff away until yer done... common error, valuable raw material as the work continues, or, as you found, you change your mind.
As noted, nothing beats the stock system. Few busnuts bother to maintain the AC portion, lots of $$$ needed to return to operation, and to keep it operating. Highest maintenance item historically in the Greyhound fleet...
Without the proper rear ductwork, it will be harder to get the heat into the rear of the coach well distributed.
It is common for the separator in the duct at the rear to be compromised, the half-assed design of some years, easily leaks between top and bottom, especially if anyone ever worked on it during a floor covering replacement, so the return and supply short circuit and the heat doesn't get back there.
Happy coaching!
Buswarrior
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Nothing beats the factory heat and air but setting for months it can drain the old pocket book every year to keep it going and the ducting system can get nasty,for heat the diesel fired with heat zone exchangers is the way to go if you can stand the noise of Webasto
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Jraynor, don't throw stuff away until yer done... common error, valuable raw material as the work continues, or, as you found, you change your mind.
As noted, nothing beats the stock system. Few busnuts bother to maintain the AC portion, lots of $$$ needed to return to operation, and to keep it operating. Highest maintenance item historically in the Greyhound fleet...
Without the proper rear ductwork, it will be harder to get the heat into the rear of the coach well distributed.
It is common for the separator in the duct at the rear to be compromised, the half-assed design of some years, easily leaks between top and bottom, especially if anyone ever worked on it during a floor covering replacement, so the return and supply short circuit and the heat doesn't get back there.
Happy coaching!
Buswarrior
yeah I still have pretty much everything that ive taken out stored in the bays. Only scraped a few things I was sure ill never need. I still have a majority of the luggage rack metal as well.
For my OTR, I'm considering ducting it to the roof and using the luggage rack fans to push it front/back. My OTR heat would be the same. For camping AC I have a 26kBTU basement unit I place to duct to the ceiling with closeable vents to distribute the air as I need and probably pull the return from the OTR system. For heat I may back feed it through the OTR return system since heat rises. Would work well for the bedrooms that would be near the return vents and probably a space heater in the front. Space heater is more convenient and less space than piping a heat system in. Still all in the air right now though
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Heat won't sink...
Heat has to be delivered at the floor, or there will be a layer of cold air at the floor, while your head sweats, and that's where the co-pilot's feet are...
Certain disaster, end of the road, if there are cold feet...
The luggage rack fans will swirl air around at that height. If you extend the intake to floor level, they will mix better, and be of more use during AC use?
Happy coaching!
Buswarrior
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Heat won't sink...
Heat has to be delivered at the floor, or there will be a layer of cold air at the floor, while your head sweats, and that's where the co-pilot's feet are...
Certain disaster, end of the road, if there are cold feet...
The luggage rack fans will swirl air around at that height. If you extend the intake to floor level, they will mix better, and be of more use during AC use?
Happy coaching!
Buswarrior
Yeah the OTR Heat will have a slight modification of how it will work. Maybe a similar duct redirection flap that can be switched with the seasons
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I have a 1989 MCI 102c3
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
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I have a 1989 MCI 102c3
I still have all of the original duct pieces that came out of my 1986 102A3. I don't currently have any plans for it other than scrap at the moment but im sure shipping would be quite a bit depending on where you live
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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.
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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.
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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.
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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.
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It's all covered up now, here is what I could find, plus a high quality architectural drawing.
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Yank that Cat and put in a 550 hp 8-92. You'll have plenty of heat.lol
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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
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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
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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.
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Cool! How big are these ducts?
Jim
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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
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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
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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
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Jraynor, do you still have that ducting?
I actually sold them about 2 months ago. Shipped them out west