York ZT078-102 Installation Manual

Also see for ZT SERIES: Technical guide

6021980-UIM-A-112022 Johnson Controls Ducted SystemsFiltersTwo-inch filters are supplied with each unit. One-inch filters maybe used with no modification to the filter racks.Always install filters ahead of evaporator coil. Keep the filtersclean and replace them with filters of the same size and type.Dirty filters reduce the capacity of the unit and result in frostedcoils or safety shutdown. See the physical data tables for thenumber and size of filters needed for the unit.Do not operate the unit without filters properly installed.Power and control wiringField wiring to the unit, fuses, and disconnects must conform toprovisions of National Electrical Code (NEC), ANSI/NFPA No.70 – Latest Edition (in U.S.A.), current Canadian ElectricalCode C221, and/or local ordinances. The unit must beelectrically grounded in accordance with NEC and CEC asspecified above and/or local codes.Voltage tolerances must be maintained at the compressorterminals during starting and running conditions. The voltagetolerances are indicated on the unit rating plate and in Table 2.The internal wiring harnesses furnished with this unit are anintegral part of the design certified unit. Field alteration tocomply with electrical codes is not required.If any of the wire supplied with the unit must be replaced,replacement wire must be of the type shown on the wiringdiagram and the same minimum gauge as the replaced wire.A disconnect must be used for these units. Factory-installeddisconnects are available. If you install a disconnect, you mustuse a field supplied accessory. See Figure 4 for therecommended mounting location.Note: Not all local codes allow the installation of a disconnecton the unit. Confirm compliance with local code beforeyou install a disconnect on the unit.Electrical line must be sized properly to carry the load.Note: Use copper conductors only.Each unit must be wired with a separate branch circuit feddirectly from the meter panel and properly fused.See Figures 20 and 21 for typical field wiring. Refer to theappropriate unit wiring diagram mounted inside the controldoors for control circuit and power wiring information.Make sure that panel latches are properly positioned onthe unit to maintain an airtight seal.208/230-3-60 units control transformers are factorywired for 230v power supply. Change the tap on thetransformer for 208-3-60 operation. See the unit wiringdiagram.Avoid damage to internal components if you drill holes toinstall a disconnect.When you connect electrical power and control wiring tothe unit, you must use water-proof connectors so thatwater or moisture cannot be drawn into the unit duringnormal operation. These water-proofing conditions alsoapply when you install a field-supplied disconnectswitch.