White Rodgers 1F90-51 - Manual (Page 5)

5
CAUTION !
RH Y
24 VAC 120 VAC
Hot
Neutral
THERMOSTAT
SYSTEM
G W
HEATING TRANSFORMER
24 VAC 120 VAC
Hot
Neutral
COOLING TRANSFORMER
Cooling
System
Fan
Relay
Heating
System
RC
G
RC
Y
W
RH
Thermostat Terminal Connections
From fan relay
From heating
system From 24 VAC
cooling transformer
From cooling
system
From 24 VAC
heating transformer
Figure 8. Typical wiring diagram for heat/cool, 5-wire, two-transformer system
RH
W
RC
G
Y
NOTE
This system does not
require RED jumper
wire (provided with
thermostat).
4. Place subbase over hole in wall and mark mounting
hole locations on wall using subbase as a template.
5. Move subbase out of the way. Drill mounting holes.
6. Fasten subbase loosely to wall, as shown in fig. 3,
using two mounting screws. Place a level against
bottom of subbase, adjust until level, and then tighten
screws. (Leveling is for appearance only and will not
affect thermostat operation.) If you are using existing
mounting holes, or if holes drilled are too large and do
not allow you to tighten subbase snugly, use plastic
screw anchors to secure subbase.
7. Push excess wire into wall and plug hole with a fire-
resistant material (such as fiberglass insulation) to
prevent drafts from affecting thermostat operation.
ATTACH THERMOSTAT TO SUBBASE
USE SYSTEM
SWITCH
TO TURN THERMOSTAT OFF BE-
FORE ATTACHING THERMOSTAT TO WALL.
FAILURE TO TURN THERMOSTAT OFF BEFORE
ATTACHING TO WALL MAY CAUSE EQUIPMENT
DAMAGE DUE TO RAPID COMPRESSOR CY-
CLING.
To attach thermostat to subbase, line up the plastic snap
guides at the bottom of the thermostat and the two
connector pins on the thermostat with the connectors
near the bottom left section of the subbase (when viewed
from the front). Gently pivot the thermostat up until the six
pin connectors and the plastic snaps lock into place (see
fig. 9). Be gentle when attaching thermostat. If the
thermostat does not seem to be attaching to the subbase
easily, make sure that the connector pins and plastic
snaps are properly aligned, and that excess wire is
pushed into the wall. Damage to the thermostat may
occur if force is used.
ENGAGE TWO LOWER GUIDES;
PIVOT UP
Figure 9. Attaching thermostat to subbase