Copyright 2019 Discovery Owner's Association, Inc.

Roof A/C Fan Modification

NOTE! Gene Hammelman has made this a simple plug-and-play project that will work with any 1995 and later Fleetwood motorhome (and other brands that use the Intelletic EMS unit). Click Here to learn more! This is an excellent alternative if you do not want to attempt this project below, but you still want to stop those noisy fans!

The way the roof air conditioners operate as they come from Fleetwood is a major irritant to most D owners. When you turn on the air conditioner(s), the high speed fan is engaged and the compressor is started. The fan continues on high speed until the room temperature is 2 degrees above the desired temperature set on the thermostat. When this temperature is reached, the fan switches to low speed. When the desired temperature is reached, the compressor is shut off. However, the fan CONTINUES TO RUN on low speed until the room temperature falls to about 5 degrees BELOW the desired temperature set on the thermostat. This causes the a/c fan to run needlessly, and will NEVER shut off unless the outside temperature cools off significantly. Even though it runs on low speed, it still makes a lot of noise.

Many thanks to John Zane for coming up with this idea that he originally implemented on his Pace Arrow. I personally have spoke with Intelletic engineers about the possibility of such a modification, and their reply was that "it couldn't be done"!

This and following web pages will explain in detail how you can make a simple modification so that your fan will shut off when the desired temperature is reached.

The D contains an Electronic Climate Control (ECC) system that is made by Intellitec. The ECC system consists of two parts:
- The ECC thermostat, which is the control panel for temperature and heat/air conditioner that is mounted inside your coach.
- The main ECC Control Module that is mounted in the space under your refrigerator (in my 98 36T). It is labeled "Electronic Climate Control Energy Management Unit Master Controller".

The purpose of this system is to allow you to operate both roof air conditioners on 30 amps. The ECC monitors the energy demand, and will operate the roof air conditioner(s) only if there is enough remaining power to do so. All of us have encountered the situation when we had one a/c shed when we used the microwave. The ECC control module is programmed to shed the rear a/c compressor first, then the front a/c compressor, then the rear a/c fan (if running) and finally the front a/c fan. If only enough power is available to operate one a/c, and the thermostat demands that both a/c compressors operate, then the ECC control module will alternate operation of the front and rear a/c every 30 minutes.

Overall, a very neat feature to have on the D. Most people that have 50 amp service cannot operate both a/c when they are only plugged in to 30 amp service. Also, they usually pay a premium for 50 amp service. So, I think overall we have a lot to be thankful for.

Now, let's get started with the modification!
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The DISCOVERY OWNERS ASSOCIATION, INC, was formed to promote the sharing of information and the camaraderie of fellow Discovery motorhome owners. Membership in the club is limited to owners of Fleetwood Discovery motorhomes.


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