Carrier 58TUA, Installation, Start-Up, And Operating Instructions Manual

The gas service pressure must not exceed 0.5 psig (14-in. wc), and
no less than 0.16 psig (4.5-in. wc).

Thermostat wire connections at R and W/W1 are the minimum
required for gas heating operation. W2 must be connected for
2-stage heating thermostats. C

OM

, Y/Y2, and G are required for

cooling, heat pumps, and some clock thermostats. These must be
made at the 24-v terminal block on the control. (See Fig. 11.)

This furnace can be installed with either a single-stage heating or
a 2-stage heating thermostat.

For single-stage thermostats, connect thermostat W to W/W1 at
furnace control terminal block. (See Fig. 9.) For single-stage

thermostats, the control will determine, based on length of previ-
ous heating on and off cycles, when to operate in low- and
high-gas heat for optimum comfort. Setup switch-2 (SW-2) must
be in the factory-shipped OFF position. See Fig. 12 and Tables 6
and 7 for setup switch information.

If a 2-stage heating thermostat is to be used, move SW-2 to ON
position at end of furnace installation. This overrides built-in
control process for selecting high and low fire and allows the
2-stage thermostat to select gas heating modes. The W2 from
thermostat must be connected to W2 on control terminal block.
(See Fig. 10.)

Fig. 9—Heating and Cooling Application Wiring Diagram 1-Stage Thermostat and Condensing Unit

A99071

115-V FUSED

DISCONNECT

SWITCH

(WHEN REQUIRED)   

JUNCTION
BOX   

CONTROL

BOX

24-V

TERMINAL

BLOCK  

TWO-WIRE

HEATING-

ONLY   

FIVE

WIRE

1-STAGE THERMOSTAT TERMINALS

FIELD-SUPPLIED

FUSED DISCONNECT

CONDENSING

UNIT   

FURNACE

COM

R

W

Y

R

G

C

GND

GND

GND

GND

GND

GND   

FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING   

208/230- OR
460-V
THREE
PHASE   

208/230-V
SINGLE
PHASE   

WHT   

BLK   

WHT   

BLK   

W/W1

W2

Y/Y2

G

NOTES: 

1.  Connect Y-terminal as shown for proper operation.

                2.  Some thermostats require a "C" terminal connection as shown.

3.  If any of the original wire, as supplied, must be replaced,
     use same type or equivalent wire.

Fig. 10—Heating and Cooling Application Wiring Diagram 2-Stage Thermostat and Condensing Unit

A99072

115-V FUSED

DISCONNECT

SWITCH

(WHEN REQUIRED)   

JUNCTION
BOX   

CONTROL

BOX

24-V

TERMINAL

BLOCK  

THREE-WIRE

HEATING-

ONLY   

SEVEN

WIRE

2-STAGE THERMOSTAT TERMINALS
   

FIELD-SUPPLIED

FUSED DISCONNECT   

2-SPEED
CONDENSING
UNIT   

FURNACE

G

R

W2

Y2

G

Y1

C

GND   

GND

GND

GND

GND

GND   

FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING   

208/230- OR
460-V
THREE
PHASE   

208/230-V
SINGLE
PHASE   

Y2

Y1

C

WHT   

BLK   

WHT   

BLK   

W1

R

W2

COM

W/W1

Y/Y2

NOTES: 

1.  Connect Y-terminal as shown for proper operation.

                2.  Some thermostats require a "C" terminal connection as shown.

3.  If any of the original wire, as supplied, must be replaced,
     use same type or equivalent wire.

10

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