Installation (Cont’d); Wiring For Two-Transformer Systems - White Rodgers 1F90 Addendum To Installation Instructions

INSTALLATION (cont'd)
Voltage
Figure 2 shows a two-transformer heating/cooling sys-
tem, with isolation relays installed in the heating (W),
cooling (Y), and fan (G) circuits. To simplify the diagram,
limit and safety switches are not shown here, although
they are found either in the low or high voltage circuit. Limit
and safety switches must be retained. Refer to the
equipment manufacturer's system wiring diagram for the
location of limit and safety switches.
RH W
Line
24 VAC
Heating
Transformer
System
Figure 2. Wiring for two-transformer systems
THERMOSTAT
Y G RC
24 VAC
Cooling Fan
System Relay
DO NOT REMOVE OR WIRE AROUND LIMIT AND
SAFETY SWITCHES WHEN INSTALLING ISOLA-
TION RELAYS.
Line
Voltage
Transformer
WARNING
!