York ZT078-102 Installation Manual

Also see for ZT SERIES: Technical guide

6021980-UIM-A-1120Johnson Controls Ducted Systems 75Smart Equipment™ UCB - LEDsLocation Label Description Function and commentsNPOWER Green UCB power indicator Lit indicates 24 VAC is present at C and 24V terminalsFAULT Red hard lockout, networking error and firmwareerror indicator1/2 second on/off flashing indicates one or more alarm is currently active,1/10th second on/off flashing indicates a networking error (polarity,addressing, etc.) or a firmware error (likely correctable with re-loadingfrom USB flash drive)SA BUS Green UCB SA bus communication transmissionindicatorLit/flickering indicates UCB SA bus communication is currently active, offindicates the UCB is awaiting SA bus communicationSmart Equipment™ UCB - optional communication sub-boardLocation Label Description Function and commentsO1Terminal FCBUSconnectionsFC+ FC (“Field Connected”) BUS BACnet MSTPcommunicationPositive of the VDC (typically, a fluctuating 1.5 to 3.5 volts reading toCOM; at least 0.25 volts higher than –) FC bus BACnet MSTPcommunication circuitFC– FC (“Field Connected”) BUS BACnet MSTPcommunicationPositive of the VDC (typically, a fluctuating 1.5 to 3.5 volts reading toCOM; at least 0.25 volts lower than +) FC bus BACnet MSTPcommunication circuitCOM Common for the FC (“Field Connected”) BUSBACnet MSTP communication circuit Negative of the VDC FC bus BACnet MSTP communication circuitSHLD Shield for the FC (“Field Connected”) BUSBACnet MSTP communication circuitEarth ground reference of the cable to prevent interference on theFC bus BACnet MSTP communication circuitQ EOLswitchEnd Of Line selector switch for the FC BUSBACnet MSTP communication circuitON selected only for the UCB that is the terminus of the FC busBACnet MSTP communication cable to prevent signal “bounce-back”PEOL Green End Of Line indicator Lit indicates the EOL switch is selected ONFC BUS Green FC bus communication transmissionindicatorLit/flickering indicates outgoing UCB FC bus communication iscurrently active, off indicates the UCB is awaiting incoming FC buscommunicationR ISO PWR Green communication board Isolated PowerindicatorLit indicates the UCB is supplying power to the communication sub-board