Have had a chance this week to do some more maintenance and mods on the Clipper and was in the area behind the center console. I took some more pictures and checked out the operation of the ACME heater/AC to make sure it was operating properly for our pending trip east.
In previous posts I have mentioned that the dash mounted slide operates the "fresh air door".
I am going to detail this further to avoid any misunderstanding of how this slide switch works.
The slide control operates an internal bypass door that directs air over, or bypasses the heater core. This door is located within the ACME 'box' and is not accessible without disassembly of the box.
Below the dash, through the bottom of the floor of the Clipper, is a door that is probably better referred to as the "fresh air door".
This door is vacuum operated and is open to outside fresh
air at all times except when the AC High
button is depressed or when the unit is turned off with the off push button.
On my Clipper I had, a number of years ago, installed a metal mesh screen on this air intake to restrict access of small unwanted visitors. As indicated above, if you have had the heater on, or the air in the low/medium settings, and shut off the ignition, this door will be left open and would be an easy access route into the air box and possibly the ventilation ducts, direct to the living quarters of the RV.
One other problem I have now pinpointed a solution for today, is lack of expected heat we have experienced in the past when operating in sever cold conditions. I always thought the heater should be able to produce more heat than it did, but I think I now know why.
Even with the heater on max., the box is still being fed fresh outside air by this door located thru the floor on the Clipper.
This would never be a problem in most localities that the motorhome would normally operate. (most users head for warmer climates
.) But I operate my Clipper north of the 49th for the most part, and have encountered many occasions where more or quicker heat would have been appreciated.
No combination of pushing buttons on the dash control will close this door while heat is demanded.
My solution to this then is to cut up a piece of vinyl material to slip over the opening and block probably 80% of the outside air from entering the box.
On the Clipper, there is a handy ledge on both sides of the intake box for the vinyl to snap into. It is easily removed and stored for hot weather as the door will close when you push the MAX button on the air conditioning control.
ACME has updated their site and all OEM parts are once again available direct from them.
Motorhome Dash AC and Heat systems