new air conditioner for brunnhilde - part 11

Mission accomplished!

This is one of the hardest enhancement project that I tackled. Starting the work just when the Oregon rainy and windy season is not for the faint of heart. Like the saying goes, failure is not an option. When I set out to explore the feasibility of the air conditioner conversion, one overriding requirement is to maintain the original integrity of Brunnhilde's interior, as well as the functionality of the Kerstner control panel.

Because of these, as well as many other self-imposed constrains and those preexisting, the design and implementation complexity increases a magnitude over a typical RV air conditioner installation.

because of the existing 3/8" diameter hole of the Kerstner fan speed control, the only option is to find a SPDT switch that has the same panel mount thread - the 3/8" nut is covered by the plastic faceplate which would be ruined if removed

i have this programmable rotary switch that I modify for this purpose; i have to cut the shaft shorter and reduce the diameter, as well as shaping the half-moon detente for the existing knob to fit

unfortunately after spending a lot of time to modify the switch I decided not to use it because for it to fit, I must rotate the thermostat 90 degrees - which necessitate enlarging the hole in the cabinet, not something I want to do for so little utility

While I wanted to keep the ability to select between high and low fan blower speed, the truth is I cannot see myself ever want to use the high speed setting because it is overkill, and extremely loud. I proceed to wire it up fixed at the low speed. I can always revisit this later if it turns out in hot and humid weather the high speed setting is necessary.

With that out of the way, one critical step is to find a place to stick it. That is where to stick the capillary tube of the thermostat. In the Kerstner setup, it is embedded in the evaporator coil. For expedience sake I try to avoid having to do the same so I fasten the tip to the air outlet port of the Mach 8 Cub. I know this would likely reduce the high set point of the thermostat.

Today I did a brief duration of testing with the Mach 8 Cub and the Eberspacher heater dueling out. Because of the low outdoor ambient one have to be careful in interpreting the result. Sure enough setting at the warmest position, the cabin temperature is regulated a bit low. It is however not unreasonable, so I feel comfortable to proceed the complete reassembly of the overhead cabinet.

I was able to reinstall all the bits, including the sheet metal electrical safety shields. I left the overhead cabinet in better condition than I started - I repaired the delaminated fiberglass inner and outer shelf that led to the sagged ceiling on the passenger side at the overhead cabinet.

All my goals achieved. The overriding is one cannot discern the air conditioner has been change from the appearance inside. I did not drill a single hole or cut any new opening in the entire project, except those of tiny screws for the duplex electrical, and for the fabrication of the air plenum inside the overhead cabinet. The Mach 8 Cub is mounted securely on the roof utilizing all 6 existing bolt anchors.

I completely removed the Onan generator's control panel and the wiring. I had planned to ustilize the vacacy to house the control of the Suburban DSI water heater. Actually when I looked at the uneven hole that Airstream cut for it versus the vertical orientation of the Suburban control my thought is the 12Vdc and antenna outlet would be a more suitable home for it. The Onan control panel site would best be used to house two 12Vdc outlets.

i think i will make a similar utility outlet panel like this for the defunct Onan control site - this is how to make lemonade from lemons

As to the fate of the Onan generator. I was just going to give it away or take it to scrap. On second thought I am toying with keeping it for home use during power outage. While the Honda generator is much quieter, the Onan can be converted (I think without having to buy the jet set at inflated price) to natural gas. The electric start would also be a party brag point.

my modest transfer panel - with the Honda 2000 set at Eco mode, I can run everything I need during power outage including furnace, fridges and freezer, internet and yes 60" LCD TV

This is one of the few clean up steps to put the icing on the cake. Another project is to restore the spare tire carrrier to the original Sprinter's design.

When I first try to turn on the Mach 8 Cub AC a few days ago, I found the thick RV 30A cable. To connect to the 120Vac outside duplex outlet of the house, I also need the adapter plug which I store under the bench seat that I could not access, because the kitchen upper cabinet was resting on the lower berth bed. What to do? I paused for a moment, and realize that I could probably just use the 15A extension cord that I use to keep the batteries charged. This extension cord has a 5-foot home made adapter shorty the convert common 15A 3-prong to the 30A RV plug. The entire setup was not meant for supporting an RV air conditioner.

I figure it would work in a pinch. The Mach 8 did not struggle at all even when the compressor first kicked in. I measured the votage at the inside outlets and it reads 120Vac with the compressor running. Because of this, I will work to not bother to carry the bulky 30A RV cable with me on trips to save precious storage space.