Parking Heater (Part 3)

Continuing the story of getting some heat into the bus while camping or parked. In Part 1, I touched on why I was doing this, how I arrived at the unit I got and what I needed to get to augment the kit so it was a viable install. In Part 2, I got into the planning, preparation and the beginning of the install. Today, I'm deep into it. This project is a little strange in that you can only go so far with one aspect before you need to get the others caught up. You'll see what I mean.

Heat Register

register mock-up

After all the destruction and time spent lying in puddles under the bus in my last post, I wanted something a little more creative and less wet. So, I moved inside the bus with a couple of cereal boxes from my recycling bin to mock-up a heat register. Judge me all you want, but Frosted Mini-Wheats are a great TV snack. Anyway, I set the heater in place and put a piece of cardboard underneath, roughly aligning with the steel grate opening. This is where science goes away and art comes in. I used the 3" vent that is supplied with the kit to give me perspective of where the register inlet would be. I considered the backside of the register could not touch the heater unit or there could be vibration noise. After a few cycles of test, measure, cut, test again, I arrived at a 3-dimensional cardboard model that fit, and should deliver the warmed air without leaking (see picture to the right).

To convert the cardboard model to something real, I just needed some HVAC flashing (be careful; it's sharp! Ask me how I know). I had intended to follow the same pattern I did with the trunk carpet in Oliver (see MGB Trunk Carpet Part 1), but it turned out my 3-dimensional model was really only suitable as a basis for taking measurements. The picture of the measurements is shared here in case someone else wants to do something like this. With dimensions in hand, I considered a few ways to go after it while I tried the measurements on another recycler-bound cereal box (Honey Nut Cheerios this time. Again, a very good TV snack). I cut one top/bottom and then the sides. The sides were simple rectangles 3" wide, spanning from the large outlet around to where the hose fit in. I concluded that I could do something very similar to the carpet on the speaker box, limiting the number of seams, and therefore cuts and extra tabs, etc.

register design

I decided to depend on DAP contact cement to hold the register together, and use no fasteners to hold it together. DAP can handle up to 180* and the heater specs say its output temp peaks at 135* so it should be a good match. Based on the website for the contact cement, I can bond the steel-to-steel with it. Then I'll go back around with HVAC tape inside the register so it is fully sealed. Considering that this is for functionality not a show-piece, I may even wrap the whole thing in that thin closed-cell insulation I have used around the various cars to help keep the hot air as hot as possible before it flows into the cabin.

With all of this in mind, I re-planned and drew a top, sides and bottom as 2 pieces on the HVAC sheet. That sheet was not quite large enough for all of it, so I created an interruption at the 3" hole, making for the smallest additional seam I could manage. The unit folded together along the 8" stretch that runs from the rear edge of the vent-to-bus to the edge furthest to the driver's side. This eliminated the longest seam. The other seams had small tabs that folded inside. I used my bench vise to help keep the lines straight as I folded the flat steel into a 3-dimensional box. The drawing can be seen in the picture to the right.

Once assembled, I test fit into the cabinet and then shifted focus again. I still need to integrate a 3" fitting / bib / inlet for the hose to attach to.

Fuel Pump Electrical

planning the cut

With a plan for the heat register, I looked at the wiring bundle. It's fairly simple. There are 3 plugs and 2 thick wires (12V supply and ground). The 3 plugs are relatively straightforward: there's a round one for the LED thermostat, a 2-pin rectangular one for the fuel pump and a large one for the heater. All three are keyed to only go one one way. The fuel pump cable is about 6 feet long, so I ran out most of it, and cut all but the last foot of it off the loom so I could thread it up into the bus from underneath. I drilled a 1/4" hole behind the auxiliary fuse box (driver's side under the rock-n-roll bed) and then slid under the bus. I plugged in the fuel pump and then ran the wire up over supports and then up through the hole, leaving very little slack, but not taught either.

The other wiring is all inside the bus. So, I climbed back inside the bus, and fished the fuel pump cable through the service opening near the rear driver tire well back into the rear of the fridge cabinet. I threaded the cable through to where the heater unit is being installed, and left things like that while I finished every thing else. I figured that I could decide to shorten wires once the heater is set, but doing it now, when the register isn't plumbed, the heater isn't bolted down, etc, was premature. It was around this point when I bolted the steel pan/sheet to the bottom of the heater. This seemed important (they wouldn't have included it otherwise). I figure it is some kind of heat shield or something.

Fuel Sourced
I ran a stretch of rubber/viton fuel line from the plastic tubing within the belly pan space to the inlet on the heater. I gave myself just enough hose so I could lift and tilt the heater to access the line. There is very little extra fuel line. The other end of the plastic fuel line for the heater is routed to the engine compartment. I intend to move the big clear plastic filter in the main fuel line down to the point where the main fuel line from the fuel tank enters the engine compartment, which is pretty much right next to the plastic line for the heater. Immediately after the filter, I will add the "T" for the heater. Rather than get into that now, I stayed with the electrical. Besides, it's cold and raining outside, and inside the bus was dry and out of the wind.

Main Power and Ground

heater grounded, but blurry

Power should have been the most straight-forward, but I just can't do simple, I guess. Consider that Hapy has 2 batteries during his in-use months: the main battery and the luxury battery. When we're camping, I'll want to source the heater off the luxury battery so we don't strand ourselves somewhere. When driving or when Hapy is off season, just parked in the driveway like now, I will want to run the heater off the only battery that's there: the main. So, with a plan to integrate a switch, I ran a 14ga (that's what came with the heater) wire from an unused battery-top 20A fuse along the familiar route: above the rear engine hatch, through the spare tire well and then forward into the little storage cabinet next to the rock-n-roll bed. From here, I ran a separate wire through to the heater, and spliced that into the harness. I had to pause that progress, since I don't have a switch handy, so I'll get back to this later. I will run a third wire from the switch to the luxury fuse box eventually. To keep things safe, I unplugged the 3-wire plug from the battery-top fuse box. I should also point out that the kit arrived with a 20A fuse, so the battery-top set-up is on-frame with the design.

For the ground, I looked around and through the various gaps in the cabinet for some exposed steel. I figured I could get at one of the side supports but that wasn't fruitful. So, I looked elsewhere. The cabinet floor had a 1" round hole just in front of where the heater unit was sitting. I think this was a drain hole for an ice-box option in the late-70's Westy. I was able to bore a hole into the steel floor there, scrape off the top paint and then steel-screw the ring terminal on the grounding wire (also 14ga) to the floor. It almost looks planned.

Intake

not an advert for Pepsy

At this point, I started to feel like this project was nearing its end. I needed to get the air intake attached to the air hose and the air hose attached to the air filter. The air hose is paper, and the aftermarket filter assumes that it is wrapping around the outside of something relatively firm, like a pipe. Those 2 characteristics don't align well. To remedy, I threaded the top of a soda-pop bottle into the foil/paper hose. Once it was all the way in, I cut the bottle off with a hacksaw. This provided the firm hose end that the air filter could attach to, so I forced it on and tightened it into place with a clamp.

I had intended to route this between the belly pan and the floor. Ya see, I have an old hole in the floor for the sink-drain when the '79 interior was installed, and I thought I would be able to maintain the air filter through that hole. I was mistaken, and probably ought to patch that hole. Anyway, the air intake hose provided in the kit was not long enough, and left me reaching around for it through that hole. There was no way I would be able to remove and re-install a filter that way. So, I was back to boring a hole. Similar to the exhaust hole, I used another drain hole as the center point for a hole saw. This hole is inboard of the exhaust hole by a few inches so the air hose will have a couple of extra bends in it. Recall that the intake hole was made smaller by the frame support. I decided to cut the steel floor between the holes so the intake could fit. Then, I sent the air hose up from the bottom. I decided to wait on attaching it to the underside of the belly pan until after I had the exhaust at least this far.

After all this, I got the comment from our old friend Hal. He indicated that the "air cleaner" is really nothing more than a noise baffle for the intake. He expressed concern that I might actually create an issue with a real air filter, so I removed the air filter. I will be wrapping the intake with some window screen or something to keep the flies out, but will not be using the air filter I got.

As usual, this post got long. So, I'm going to stop here. More next time and thanks, as always, for following along-