Carrier 42V - Manual (Page 64)

64
Thermostatic Valve Control, 4-Pipe — The 4-pipe system
provides the ultimate in economy and room temperature con-
trol. Both hot water and chilled water are available at any time.
Normally an automatic changeover thermostat is used, but a
manual changeover thermostat is also suitable. Two 2-way
valves, two 3-way valves, or one 2-way plus one 3-way valve
must be selected. An automatic changeover device to sense
water temperature is not required.
With this system, the fan runs continuously unless it is
manually switched to OFF position. Fan must be on before
thermostat can send signal to open the chilled water or hot
water valve.
NOTE: Wiring diagrams are for 120-v power supply. If other
voltages for heaters or controls are specified, wiring may differ
from that shown. See Fig. 65 and 66 for line voltage control.
See Fig. 67 and 68 for 24-v control.
Fig. 65 — 42SG,SH,SJ,VA,VB,VC,VE,VF 4-Pipe Heating and Cooling —
Unit-Mounted Thermostat (Line Voltage)
a42-4079
120-V WHT ALL OTHERS BLK

NEC CLASS 1 WIRING