Proper attention to maintenance checks will often allow you to detect developing troubles in time to take corrective action. Since most breakdowns often occur at the most inopportune time, periodic checks and maintenance will prove to be well worthwhile to avoid malfunctions.

The two-position control system can easily be checked out in a reasonably short time. The checkout period should be at least every three months or more often if it proves to be necessary. Inspection and checks should be conducted at the beginning of the cooling season and about mid-way. The same should be done for the heating season.

Sensing elements should be inspected and any dust accumulations removed. Thermostatic sensing elements should have dust and dirt re-moved with a soft brush, and the sensing elements in humidistats should be blown off gently with air so as not to damage the elements. Magnetic valves should be checked for operation. Be sure that the valves are opening and closing completely.

Setpoints of the thermostats and humidistats should be checked with a calibrated thermometer and a reliable humidity indicator.

When servicing the two-position control system there are three possible areas where trouble may occur:

1. The sensing element and its associated mechanism.

2. The magnetic valves that control the flow or refrigerant.

3. The wiring system which connects the sensing elements to the solenoids of the magnetic valves and the controller of the electric heaters.