Parking Heater (Part 2)

Today's post continues my process of introducing an experimental parking heater into the microbus. My main driver for this was our 4Peaks Music Festival experiences. Even though it is around the Summer Solstice, every year, the overnight temperature gets down into the mid-30F's (that's like 2*C for our non-US friends). That had caused us to us the Little Buddy heater a lot, heating up the tented-zone outside the bus while hanging out and then again inside the bus before going to bed. I figured if we had something dedicated to the bus, the little propane heater could just focus on keeping the hang-out zone tolerable. Aaand... the bus could be pre-warmed either while we were away at the stages or while we were sleeping.

Planning

blurry picture of test fit

It all starts with determining where you want to install it. I chose the old fridge cabinet because it had a false floor as well as a metal grate I could send the warmed air through. The air supply-side would just pull from under the cabinets and the bed; these are the coldest zones, so that should work great. The fuel and exhaust needed to get through the wood floor of the cabinet, the steel floor of the bus and the belly pan unique to the early 70's bus. I figured that I could source the combustion air from between the floor and the belly pan since there were multiple holes that would allow air to freely flow.

I will "T" off the diesel line from the main tank, and not use the kit-included second tank just for the heater. I figure I can introduce the "T" after the large clear filter so I won't need the tiny one shipped with the kit that does not look as hardy.

Preparation
Before I could start installing, I needed to remove the false-floor. I would have liked to reuse that floor, but the way it was installed made that impossible. So, with a 1" paddle bit on my drill, I bore multiple holes into the floor until I could smash it into pieces. Once the chunks were out, I cleaned up all the edges, removed the little bits of fasteners (staples and short wood screws) and shop-vac'd the thing out. Once it was gone, I could really evaluate my options. There were only so many ways the heater could go in, so I ended up with it just inside the outer wall and an inch or so in front of the rear wall (see blurry picture). This created the most room for the air intake while creating the least dramatic curve to the outlet hose. The picture doesn't really show it, but there are 1/2" gaps along the rear edge and a modest sized hole along the outer edge near the front. So, air will be able to enter without fighting a vacuum condition.

The outlet hose will still need to bend about 270* before entering a heat register that I will need to custom construct. For a mental picture, imagine a floor register in your house. It changes a 4" (or greater) diameter air hose into a rectangular shape. I could bore a 3" hole in the front of the cabinet, but I wanted this to be total stealth, and, honestly, this way was more fun. Most US housing is done with venting that is larger than 3" in diameter, so this would be a total fabrication.

Boring

fuel pump install

The heater unit delivers with a metal sheet that rests on the floor between the heater and whatever surface it is bolted to. I loosely taped the metal sheet to the heater and when I had set the heater where I wanted it, I pushed the metal sheet off, and I had a template for where the holes needed to go. I marked them with a pen, found the center-point of the holes and drilled a pilot hole in the wood cabinet floor at that center-point. I grabbed a hole-cutter for a 1-1/4" hole and drilled out the holes for the intake and exhaust. With a hand saw, I connected them together, making one single oval. I test fit the heater to make sure it dropped into the hole as intended.

With the same bit, I cut holes in the floor of the bus directly beneath the two I had just cut. The front hole went through beautifully. The rear hole, however, was partially blocked by a support running side to side. I'm a little concerned for how the air intake will need to adjust for that. With the holes in the floor, I could see one of the drain holes below and a little in front of the front hole I had just cut. So, I went underneath and bore a hole, using that drain as the center-point. I will route the exhaust out there.

Fuel
After a couple attempts, I arrived at routing the fuel from the front right corner of the engine compartment back along the stock fuel line path, then over the suspension support, along the emergency brake tube, past the nose of the transmission and then over to the passenger side along a cross support. To the rear side of this support nearest the passenger side frame rail, I attached the heater's fuel pump (see picture). The plastic fuel line would pass over the top of the frame rail and enter the space between the belly pan and the floor between the frame rail and the floor. Once I had the fuel line laid out and zip-tied in place, I installed the line to the pump with short sections of 4mm fuel line. I will caulk around where the fuel line passes into the belly pan space so vibrations do not slowly create a weakness in the line.

I figure I am maybe 1/3 done on this, so there's plenty left to do. I have the electrical, finishing the fuel, fabricating, installing and routing to a heat register, the air intake and exhaust. Then, I will test the heater, measuring the noise level and experiment with suppression ideas. I figure it'll be 2 more posts before it's all done at this rate.

As always, thanks for following along and more next time-