The purpose of a compressor short-cycle timer is to __________.

• A. prevent the compressor contactor from re-energizing before system pressures can equalize
• B. extend compressor run time
• C. delay thermostat signal
• D. control outdoor fan speed

Answer: (A)

The main idea here is protection against rapid on/off cycling of the compressor. After the compressor turns off, the pressures in the system need a moment to equalize and the oil needs to settle back toward the crankcase. If the compressor were allowed to restart immediately, you’d get a high inrush current, large pressure differentials, and increased wear on the motor and valves. The short-cycle timer adds a deliberate off-time before the contactor can re-energize, giving the system a chance to stabilize. This reduces compressor wear, improves reliability, and helps prevent nuisance short cycles.

The other options don’t fit this purpose. It doesn’t set out to extend run time or change outdoor fan speed, and while it effectively delays a restart, it does so as a protection measure rather than delaying the thermostat signal itself.