Preliminary Testing

Start the engine, place control head selector lever in AUTO position and set temperature dial at "75". Allow sufficient time for engine to warm up and for system to come on (if system does not come on, install tester and proceed with tester procedure). If system does come on, rotate temperature dial slowly back and forth and check for malfunctions in operation; then move selector lever to each position and check for malfunction in operation. Noting the malfunctions and when they occur will assist in isolating the problem to a particular part of the system.