I just completed the adaptation of a 5,000 BTU Frigidaire to work with Compass Rose. This was actually a very inexpensive process as I used a close out Frigidaire 5000 BTU that I picked up end of season at Lowes for $50. I had an adapter made to handle a 4 inch ducts by one of the local heating and air conditioning contractors. I had originally thought of using a rather fancy digital thermostat but found that making it play well with the air conditioner was not going well, plus every time it was unplugged I would lose all the settings. What I ended up doing was pulling the thermostat out of the AC unit and mounting it and on off switch in a RadioShack project box. Wiring is very simple because with a thermostat all I'm doing is looking into the existing wires that control the AC unit, and the power switch basically interrupts the off, cool, fan speed switch. I figured that the unit would be on high cool all the time, or off as I am pushing air through 4 inch flex duct. Control wires are connected using Anderson power poles and run through the air intake duct. The ducts run through four-inch Marine deck plates in the side of the trailer.
I ended up having a serious problem with the initial set up and that was icing and the discussion of that is much later in the responses on page 3. The solution however was quite simple, I added in a 4" marine bilge blower rated a 240 CFM and this has taken care of the problem. The pictures are at what is currently the bottom of this first posting. I do need to refine how this goes together and I will edit the final solution. my feeling is that I can reduce the speed of the blower and the noise produced and now that I know that it works shorten hose and route wires neatly and efficiently.
This is the electrical guts, VERY simple, Note the absence of the thermostat.
Here are the housing and adapter prepped for paint.
This is the inside of the adapter. Note the felt strip to seal the opening to the AC
The duct is the same one I used for the diesel heater good up to 450 degrees and you can see the plastic reducer wrapped up with closed cell neoprene to achieve a watertight fit.
Here is the finished adapted unit plugged into a GFI outlet. Note that the AC unit can sit entirely underneath the trailer.
On the anterior I used standard RV type duct outlets that have a wide enough spacing to allow me to run the control cables through. And yes I need to box in the outlet.
This the version II of the computer case fans. There is enough room between the fans and the event that they can be left on and help circulate the air within the trailer so that you don't get stratification with the cold air sinking to the bottom.
Here is the AC control on off and temperature, where it will end up is still open to debate and it will probably be attached using Velcro.
AC unit with handle
Blower in line.
Crossroads of America Gathering was the real life test of the system with temperatures in the upper 80's high humidity and no breeze. Saturday night it did not cool off much and we left it running all night. Come morning it was covered with condensation and you can see that.
The bilge blower is three speed, full, and with the use of resistors in the negative line, medium and slow. I found that the slow was sufficient to overcome the restrictions in the air movement enough to prevent freezing. My next step will be trying a PMW to regulate speed. The resistors get HOT and while I sandwiched them between a couple of pieces of aluminum to help dissipate that I hate wasting that much energy.
The latest is that I wanted to see how it withstood weather so left it attached and running and exposed during a thunderstorm with no ill effects. The PMW works great for regulating the blower speed, until you cross wire it, I will be getting another one this week.