In the short cycle timer circuit, the yellow wire from the thermostat to the timer is connected to terminal _________.

In the short cycle timer circuit, the yellow wire from the thermostat to the timer is connected to terminal _________.

• A. T2
• B. T1
• C. R
• D. C

Answer: (B)

In a short cycle timer circuit, the control signal from the thermostat must enter the timer through its input terminal so the timer can start its delay cycle when the thermostat calls. The yellow wire from the thermostat is the signal line that carries that call, so it is connected to the timer’s input terminal, T1. Inside the timer, T1 and T2 form the switch that, after the delay, completes the circuit to energize the rest of the control wiring. The other terminals, R and C, supply 24 VAC power to the thermostat and timer, respectively, but they are not the signal path for the thermostat’s call. Therefore, the correct connection for the yellow thermostat wire is T1.

In a short cycle timer circuit, the control signal from the thermostat must enter the timer through its input terminal so the timer can start its delay cycle when the thermostat calls. The yellow wire from the thermostat is the signal line that carries that call, so it is connected to the timer’s input terminal, T1. Inside the timer, T1 and T2 form the switch that, after the delay, completes the circuit to energize the rest of the control wiring. The other terminals, R and C, supply 24 VAC power to the thermostat and timer, respectively, but they are not the signal path for the thermostat’s call. Therefore, the correct connection for the yellow thermostat wire is T1.