Carrier 42 SERIES Application Data

STANDARD WIRING PACKAGES (cont)Thermostatic Valve Control, 4-Pipe — The 4-pipesystem provides the ultimate in economy and room tem-perature control. Both hot water and chilled water are avail-able at any time.Normally an automatic changeover thermostat is used, buta manual changeover thermostat is also suitable. Two 2-wayvalves, two 3-way valves, or one 2-way plus one 3-way valvemust be selected. An automatic changeover device to sensewater temperature is not required.With this system, the fan runs continuously unless it ismanually switched to OFF position. Fan must be on beforethermostat can send signal to open the chilled water or hotwater valve.NOTE: Wiring diagrams are for 120-v power supply. If othervoltages for heaters or controls are specified, wiring may dif-fer from that shown.For control package descriptions, see control componentssections entitled Remote-Mounted Controls and Unit-Mounted Controls.UNIT TYPE LOCATION WIRING PACKAGE* ELECTRICVALVEAutomatic System Manual SystemVertical Unit Mounted 24-P Available on Special Order. Any 2- or 3-way,2-position valvepackage.VerticalorHorizontalWall Mounted 22-G, 22-H,23-07, 23-08 23-13, 23-14*Packages on current price pages.NOTES:1. Motors thermally protected.2. Use copper conductors only.3. See unit nameplate for power supply. Provide disconnect meansand overload protection as required.8