June 23, 2018, 03:04:37 PM

Author Topic: Heat & AC Choice and Why?  (Read 6501 times)

Offline JackConrad

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Re: Heat & AC Choice and Why?
« Reply #15 on: February 03, 2008, 12:43:11 PM »
   We installed our ProHeat in the middle bay on the driver's side. It is just inside the door and against the front bulkhead of this compartment. I used the 90 degree sweep that came with the used ProHeat we purchased from Nimco. I added a short length of exhaust tubing to extend the exhaust a couple inches past the edge of the bus.
   So far, we have had no problems with the exhaust hitting on anything. This includes several trips through cow pastures at Bluegrass Festivals. Jack
« Last Edit: February 03, 2008, 02:21:08 PM by JackConrad »
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Offline rv_safetyman

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Re: Heat & AC Choice and Why?
« Reply #16 on: February 03, 2008, 03:14:13 PM »
Hi Jack.  I just replied to the over-the-road AC thread and will post that information again later in this post.

We installed three Carrier roof air (cost/ease of installation and replacement/lack of bay space).  They are noisy, but we can manage that a bit by running the ones  more remote from where we are located.  I have thought a lot about how I would do it if we did another bus (no way :o) and I would do the same thing, except I would use the new low profile units (not available when we installed ours).

For heat I bit the bullet and bought an AquaHot.  I have never regretted that decision.  It is absolutely a great system.  It was a relatively easy installation.  The heat exchangers produce instant heat and do not dry out the air like forced air systems.  Provides great domestic hot water supply and can preheat the engine.  Lots of dollars, but we spend more time than we would like in cool/cold conditions.

Now for the dash air:

I installed a Red Dot 5045 and it is a great unit.  It is rated at 46K BTU heating and 33K cooling.  Think about it, that is more than two roof airs!

It fit very nicely under my new dash.  I have attached a photo that sort of shows the installation.

The unit has a cable controlled flapper that diverts the air flow from the front four fully adjustable outlets to the back opening.  On the back I made a plate with 4 outlets that connect to the defroster outlet hoses.

I plumbed the heater to my AquaHot and that really makes a really nice setup.  This morning is was a bit cool, so I fired up the Red Dot and had great heat flowing towards the passenger seat where I was sitting.  I can defrost the windows without even starting the engine!  The heat going down the road has been sufficient for any condition we have encountered (have been in Zero degree weather) while going down the road

The AC is absolutely great and can handle most any condition we have encountered except heading west in the late afternoon on a hot day and even then it makes the drive bearable.  My bus is not well insulated and still has some air leaks that I am working on.

Jim Shepherd
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Offline Nick Badame Refrig/ACC

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Re: Heat & AC Choice and Why?
« Reply #17 on: February 03, 2008, 04:21:14 PM »

How did you run your exhaust on you Proheat? Is it OK to run an elbow just under the bay floor and out to the side? Could not quite tell from your Picture. I'm worried about the pipe being too low and getting knocked off or bent. I was considering putting my Proheat in the second bay, passenger side in front of our hot water heater. That's about the only room I have left.



Hi Paul,

Yes, it exhausts out the bottom like Jacks but, I made it removeable. You can see in my pic that it is laying in front of my Proheat.
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Re: Heat & AC Choice and Why?
« Reply #18 on: February 03, 2008, 04:28:42 PM »
remember Paul the unit exhausts at around 600 degrees so be safe 


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Re: Heat & AC Choice and Why?
« Reply #19 on: February 03, 2008, 04:54:56 PM »
Hi Clifford,

I know it's gets pretty hot, that's why I'm concerned about the exhaust location. I was also worried about using an elbow, thinking of any restrictions that might hinder proper exhaust flow. Thanks for the concern.


Thanks, that's what I thought, wasn't sure.


Thanks for your description. I just don't want to knock something off. So far I haven't been in any cow pastures, just darn steel fence posts seem to not want to budge much.


Offline Len Silva

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Re: Heat & AC Choice and Why?
« Reply #20 on: February 04, 2008, 05:03:13 PM »
I had a basement air unit in my 4104 and now have two rooftops in my MH.  Can't tell you how much I hate them. Noisey, can't sleep with ther bedroom unit on and have to run the front with a box fan to cool the bedroom.  That eliminates closing off the bedroom for privacy if we have guests.  Also have condensate drips if the humidity is high.


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Offline Lin

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Re: Heat & AC Choice and Why?
« Reply #21 on: February 08, 2008, 04:16:30 AM »
I agree with the complaint about roof top unit noise.  On one of my past motorhomes, I installed a line voltage thermostat so the A/C would only come on when cooling was required.  It seems that, particularly in the bedroom, it would be running just the fan most of the time.
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Offline PP

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Re: Heat & AC Choice and Why?
« Reply #22 on: February 10, 2008, 04:08:10 AM »
We have 2 basement AC units (1-front and 1-rear). Thermostatically controlled fan over bed keeps the rear relatively comfortable in most climes at night without a lot of noise. Although we have 2 toe kick heaters, the wife hates them because they make too much noise (BUZZZZZZ) We Have 3 CAT Platinum wall mount heaters that run on 12V+propane-they're quiet, vented outside (No excessive moisture) and they put out a lot of heat on relatively little fuel. Love them. With one in the bedroom, one in the bathroom, and one in the kitchen counter facing into the lounge, they really keep it toasty in here at any temp.
Didn't want the warts on the roof but gave in for the satellite, LOL Wife's got to have her TV, don't ya know.

Offline Jerry Liebler

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Re: Heat & AC Choice and Why?
« Reply #23 on: February 11, 2008, 12:15:55 AM »
     How will I answer?  "What Did You Use For Your Heat & AC and Why?"  The what portion is easier than the why.  My heat is from a Webasto, diesel  coolant heater and 6 fan coil heat exchangers.  And supplemented in moderate cold by an 18,000 BTU/h heat pump of the ductless minisplit variety.  My air conditioning is primarily the ductless mini-split but suplemented by a 9,000 BTU/h window unit mounted through my rear cap.   The whys for the heating system  choice of the Webasto include: the ease of engine preheating, engine heat use while driving and common fuel with the bus.  The choice of the heat pump heat is related to my desire to never winterise and keep the bus above freezing all winter, in Kentucky, using relatively economical electric power.  While sitting plugged in during the winter the  Webasto serves as back up heat if it gets really cold.  The air conditioning choices were made to avoid raising the height of my bus above what could fit into my barn's doors  11'9".  A second goal in coosing my AC was energy efficiency.  I wanted to be able to be comfortable inside while it is 90+ outside and do it on 15 amps or less.  The 18,000 BTU/H mini-split has worked out really well in this regard.  It cools the inside to 70 sitting in the sun with outside temperature of 95 and does it on under 14 amps of 120 volt power.
Since the window unit in the rear uses only 820 watts and it easily cools the bedroom we are able to sleep in comfort even on battery power.
Jerry 4107 1120

Offline Paul

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Re: Heat & AC Choice and Why?
« Reply #24 on: February 14, 2008, 04:30:03 AM »

The AC is two Carrier 15.000BTU roof top, ducted, low profile units to save bay space and labor.
The sticker on dash states that the bus is -------------------------------11’ 5”.
10” roof raise =   ----------------------------------------------------------- 12’ 3”   
Remove roof hatch subtract 2.5”   --------------------------------------- 12’ ½”   
Carrier low profile is 7.5” high   ------------------------------------------12’ 8”

With a level on top of roof AC and Bus aired up, I get a Measurement of 12’ 7’ to ground.   

I drop the Ceiling down 7” this gives us 6” of space above the ceiling in center of bus to install AC duct.  The 6” changes to 4” in center with 2” of spray foam over roof ribs
I will have a Ceiling height in side of bus of 6’ 8” after installing 1 ½ Dow Blueguard Styrofoam Insulation on floor and ¾ plywood over insulation.

If I had, it to do over again the roof raise would be 12” and still drop the ceiling down 7” in the center. This would be a total height of 12’ 10” the same as an 8” raise with regular roof top Air conditioners units.

For heat, we have a Hydro-Hot unit. The Pex tubing is smaller then air ducts to save space in bus and easy insulation.  In the old bus air duct we installed three 1 ½ conduits, two 1”and two ¾” The old air duct is the place I understand most people run the new ducts for heat.

Our Hydro-Hot is a new type that requires an 18” x 15” opening in the floor. Were we are installing the unit in the back/water bay I had to cut rib under the floor of the bay for the opening. Fabricated an 18” x 15” frame out of 1 ½” square tubing to replace the rib removed. There is a 27 ¼” x 18 ¼” tray that sits on the floor with a flange opening 18”x15” down threw bay floor new opening. I fabricated a stainless steel collar/flange to install from the bottom up. The bay floor has 1 ½ Dow Blueguard Styrofoam Insulation and ¾” plywood. The tray flange was not long enough to go all way through the Floor. The tray/flange and Collar/Flange telescope to fit the opening. The Air intake and exhaust are in this opening. The Hydro-Hot unit fits in the tray.
I installed two conduits to push my ¾” heater hose threw for engine preheating. Very EZ to push will be great for replacing hose.  The hoses are attached to valves on the engine and turn off.  Have tap into the fuel tank, run 3/8” OD cooper tubing supply, and return to unit.

1988 MCI 102A3 /8V92 /740 /10" Roof Raise


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Re: Heat & AC Choice and Why?
« Reply #25 on: February 26, 2008, 05:42:02 AM »
I've not done mine yet but have been collecting parts. I have a Hurricane 61k btu hydronic heating system and plan to install a central air setup in the basement. Don't know which one yet. The reason for the basement air is because I want to have a deck on the roof and want to keep it cleaner up there. I figure I have to have vents, sat dish, and hopefully solar panels so that will fill up any roof that the deck don't cover. the Hurricane I got because it is an all-in-one unit that takes the place of a lot of other little units.