White Rodgers 1F97, 1F90 User Manual
1F90 and 1F97
CAUTION
!
WARNING
!
WHITE-RODGERS
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.
If in doubt about whether your wiring is millivolt, line, or low
voltage, have it inspected by a qualified heating and air
conditioning contractor, electrician, or someone familiar
with basic electricity and wiring.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical
codes and ordinances.
WHEN THIS THERMOSTAT IS CONNECTED TO SOME
SYSTEMS THAT USE HIGH IMPEDANCE INPUT ELECTRONIC MODULES, YOU MAY OBSERVE THE FOLLOWING CONDITIONS.
1. The furnace fan may turn on when heat has not been
called, or may not turn off when thermostat is satisfied
and call for heat ends.
2. The furnace may not turn off when thermostat is
satisfied and call for heat ends.
3. The air conditioner may not turn off when thermostat
is satisfied and call for cool ends.
Addendum to
INSTALLATION INSTRUCTIONS
PRECAUTIONS
To prevent electrical shock and/or equipment
damage, disconnect electric power to system, at
main fuse or circuit breaker box, until installation is complete.
Do not short out terminals on gas valve or primary control to test. Short or incorrect wiring will
burn out thermostat and could cause personal
injury and/or property damage.
INSTALLATION
If you observe any or all of these conditions after installing
thermostat, you can correct system operation by installing
isolation relays between the thermostat and the electronic
ignition module. Figures 1 and 2 show how three isolation
relays can be installed [one each for the fan (G), heat (W),
and cool (Y)]. You may not need to install all three isolation
relays to correct the operation conditions.
THERMOSTAT
Red Jumper Wire
RH W Y G RC
Line
Voltage
Transformer
Figure 1. Wiring for single transformer systems
24 VAC
Heating
System
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
R
ST. LOUIS, MISSOURI 63123-5398
Cooling
System
Figure 1 shows a single transformer heating/cooling system, 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 will be 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.
Fan
Relay
DO NOT REMOVE OR WIRE AROUND LIMIT AND
SAFETY SWITCHES WHEN INSTALLING ISOLATION RELAYS.
PART NO. 37-5426A
Printed in U.S.A.
9507
INSTALLATION (cont’d)
WARNING
!
THERMOSTAT
RH W Y G RC
Line
Voltage
Transformer
24 VAC
Heating
System
Figure 2. Wiring for two-transformer systems
Figure 2 shows a two-transformer heating/cooling system, 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.
Line
Voltage
Cooling
System
Fan
Relay
24 VAC
Transformer
DO NOT REMOVE OR WIRE AROUND LIMIT AND
SAFETY SWITCHES WHEN INSTALLING ISOLATION RELAYS.
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