M1 while sending a signal to one of the "CFAN" terminals on DC.
•Relay RY1 controls the crankcase heater (CCH1). The normally closed contacts allow CCH1 to operate during unit shutdown.
•Contactor M1 controls compressor COMPR1.
The output signal from the remaining "CFAN" terminal on DC closes the coil of contactor M3.
• Contactor M3 controls outdoor fans ODFAN1 & 2.
After completing the specified time for fan
•Relay BR1 sends a 24V signal to G1 of terminal block TB2. It may be used to control operation of an indoor blower.
When the call for cooling (Y1) is satisfied, the UCB disables the signal to RY1, M1 and DC as long as the specified minimum run time (ASCD) has elapsed.
The UCB disables the signal to BR1 after completing the fan
Dual Stage Heat Pump (PC120-240)
A two stage thermostat is required to operate the heat pump in cooling mode.
The reversing valve is energized during cooling mode. A continuous 24V signal is passed through the normally closed contacts of relay RY2 to the "O" terminal of the Defrost Control Board (DC). The normally closed relay
When the thermostat calls for
•Relay RY1 has two functions. 1) control the crankcase heater CCH1, 2) control the 24V output signal to S1 on terminal block TB2.
•Contactor M1 controls compressor COMPR1.
The output signal from the remaining "CFAN" terminal on DC closes the coil of contactor M3.
• Contactor M3 controls all outdoor fans.
After completing the specified time for fan
•Relay BR1 sends a 24V signal to G1 of terminal block TB2. It may be used to control operation of an indoor blower.
When the thermostat calls for
•Relay RY2 has two functions. 1) control the crankcase heater CCH2, 2) control the 24V output signal to S2 on terminal block TB2.
•Contactor M2 controls compressor COMPR2.
If the initial call for cooling requires both stages (Y1 and Y2), the UCB will delay the second stage by 30 seconds to avoid an excessive power inrush.
When the call for cooling (Y2) is satisfied, the UCB disables the signal to RY2 and M2 as long as the specified minimum run time (ASCD) has elapsed.
When the call for cooling (Y1) is satisfied, the UCB disables the signal to RY1 and M1 as long as the specified minimum run time (ASCD) has elapsed.
Dual Stage Heat Pump - 4 pipe (PD180-240)
A two stage thermostat is required to operate the heat pump in cooling mode.
Both reversing valves are energized during cooling mode. Continuous 24V signals are passed through the normally closed contacts of relays RY2 and RY3 to the "O" terminals of their respective Defrost Control Boards (DC1 and DC2). The normally closed relays
When the thermostat calls for
•Relay RY1 has two functions. 1) control the crankcase heater CCH1, 2) control the 24V output signal to S1 on terminal block TB2.
•Contactor M1 controls compressor COMPR1.
The output signal from the remaining "CFAN" terminal on DC1 closes the coil of contactor M3.
• Contactor M3 controls outdoor fans ODFAN1 & 2.
After completing the specified time for fan
•Relay BR1 sends a 24V signal to G1 of terminal block TB2. It may be used to control operation of an indoor blower.
When the thermostat calls for
•Relay RY2 has two functions. 1) control the crankcase heater CCH2, 2) control the 24V output signal to S2 on terminal block TB2.
•Contactor M2 controls compressor COMPR2.
The output signal from the remaining "CFAN" terminal on DC2 closes the coil of contactor M4.
Johnson Controls Unitary Products | 19 |
