Duo-Therm Control Center Repair

My RV is equipped with a Duo-Therm Comfort Control Center that controls two roof air conditioners with heat strips. After it became progressively more difficult to change the climate settings using the panel's buttons, I decided to purchase a new unit. Lo and behold, I discovered that the four-button control had been discontinued several years ago. I was told that I would have to buy a five-button control center, plus a new circuit board for each air conditioner. While the price varied by source, the cost would come to more than $400 plus installation. So, I decided to examine the switches and discovered that my problem would actually be simple to fix.

Here's what was causing the problem. After many years of use, the brass contact switches had bent, and some of them were no longer making contact to create a good circuit, resulting in difficulty in selecting the desired setting. The following solution corrected this problem.

First, turn off the air conditioner switch. Remove the control from the wall plate using a tool to spring the retainer at the bottom rear. Unplug the telephone line. Remove the four screws holding the cover on the circuit board. Carefully release the clip on each side of a button, holding the button so it won't pop off. (Longer clip toward the on-off switch; spring goes onto peg.) Carefully lift the button from the base. There are two brass pieces inside each switch that you must individually remove. Observe carefully so you know how to replace them when ready. Lay the brass piece on its solid side with the three legs up. Notice the small elbow bend in each of the arms. The problem is that over time, the bend in the arm has straightened just enough so that it does not make contact with the solid back when the button is depressed. To correct this problem, push in on one end of each arm to make a sharper kink in the arm, thus shortening it enough so that it will make contact with the switch when the button is depressed after the unit has been reassembled.

 Only the outside arms on the right side are in the circuit. Before bending, try switching the two brass contactors, one switch at a time.

© Barry Brideau 2007