Best AC Replacement, 24' Moho?

[Elisa]

We want to replace the original AC in our 1977 24' motorhome. Our front dash air is not working, so I want something that will cool the whole space and can run off the generator while driving.

The old one kept throwing a breaker during our trip from NY to FL a weekago. It got up to 110 degrees, a sauna on wheels. I thought I would die.

Suggestions, compadres?

[bkahler]

Elisa,

Fix your dash AC so it works and replace the roof AC with whatever AC unit fits your budget. I wouldn't even consider driving one of these motorhomes without the dash AC working.

I've been working on Peanut's dash AC and it's a pretty straight forward system to work on and for replacing parts. You can see Peanut's thread and also there are a log of comments from Gregg Wallace who has also repaired his 77 dash AC.

The roof AC unit is a pretty straight forward swap for a new unit.

Brad

[Elisa]

Brad, Please send me direct links to your dash AC info as well as the other guy's info. I still have a terrible time searching on this forum.
Thank you, thank you!

[bkahler]

Start reading at post 131 in Peanut's thread. That's where I start discussing the needed repairs to Peanut's dash AC. Information will be scattered through out the rest of the thread so just keep reading. Gregg Wallace's post should be particularly helpful. I have more information to add but I'm not quite ready to do so. I want to wait until I actually assemble the AC system before adding it.


Brad

[GWallace]

Elisa,
The heating and AC in the 77's were completely separate. The dash AC is essentially a system like the add on dash AC system in autos of the 60's and 70's and was made by Chevy. There is an evaporator unit mounted up under the dash with hoses extending to the registers that you see in the dash. The controls are the two knobs at the bottom edge of the dash in the center. One knob is to turn the system on and select the fan speed. The second knob is the AC thermostat. This system is a typical expansion valve AC system originally using Freon 12. Properly converted with barrier hoses and a newer design condenser outside, this system works well with the newer 134a refrigerant. Even in mild weather the front seats get quite uncomfortable without the dash air. I reworked my system last year. If your system is not repairable the dashboard can be removed and a complete new system can be installed as I did last year. After the new system is installed, the appearance of the system will look as it does now on the inside.

The dash heater controls are in the dash with the controls incorrectly labeled. There are three levers. One is the small one on the left for the fan speed. The bottom position is OFF. The middle position is low speed and the top is high speed. The top slide control directs the air output with all the way left FLOOR, middle FLOOR and DEFROST, and all way to the right DEFROST only. The lower slider is the heater temperature control. All the way left is OFF and higher temperature as the slider is pushed to the right. This temperature is not very precise as it controls a water control valve that is somewhat troublesome. The actual heater unit is a school bus type of heater unit mounted against the firewall in front of the passenger's feet. I have changed the control valve in my 77 to an"H" bypass valve for more precise temperature control.

The roof air is a unit made by Armstrong. They are good units when working properly and with the right technician are repairable. Some people advocate repairing if possible. Otherwise as Brad suggests a new replacement properly installed will work great. My original Arstrong unit is still running after all of these years.

The coach heater is a Suburban propane unit mounted in the cabinetry toward the rear.

Gregg

[Gregsch]

About any roof mounted AC will work. I went with the Coleman Mach 8. Many have commented that the Mach 8 is noisy . I really don't see it as a big deal. Whatever unit you buy be sure it is set up to drain to the condensate drain line and not to just dump condensate on to the roof a some do. With the Mach 8 you must specify the condensate pump option when you place your order.