White Rodgers B436777 User Manual

CONTENTS

Installation Instructions for

Heating & Air Conditioning

1F72

5/2 Day Programmable
Heat Pump Thermostat

Y OUR THERMOST A T REPLACES

Description

Heat Pump (No Aux or Emergency Heat) Yes
Heat Pump (with Aux or Emergency Heat) Yes
Standard Heat & Cooling Systems No
Standard Heat Only Systems No
Millivolt Heat Only Systems – Floor or Wall Furnaces No
Standard Central Air Conditioning No
Gas or Oil Heat No
Electric Furnace No
Hydronic (Hot Water) Zone Heat – 2 Wires No
Hydronic (Hot Water) Zone Heat – 3 Wires No

Preparations.................................................. 1

Thermostat Details ........................................ 1

Removing Old Thermostat .........................1-2

Mounting and Wiring ..................................2-3

Check Thermostat Operation ..................... 4-5

Programming your Thermostat ..................6-7

Specifications ................................................ 7

Troubleshooting .........................................7-8

PREPARATIONS

1

Assemble tools required as shown below.

HAND OR POWER
DRILL WITH 3/16 INCH
DRILL BIT, IF NEEDED

FLAT BLADE SCREWDRIVER

SPIRIT LEVEL OR PLUMB BOB AND LINE OPTIONAL—

THERMOSTAT DOES NOT NEED TO BE LEVEL TO WORK PROPERLY

WIRE CUTTER/STRIPPER

Failure to follow and read all instructions carefully
before installing or operating this control could cause
personal injury and/or property damage.

THERMOSTAT DETAILS

2

Mounting

hole

W903

Clip to

Disable

EMR

Feature

W904
Clip for
Celsius

W905

Clip for

Slow Cycle

Figure 1. Thermostat base

Mounting

hole

Terminal
Switches
Selection

W906 for Emergency

Heat Second Stage

Fan Control

O/B

REMOVING OLD THERMOSTAT

3

CAUTION

!

To prevent electrical shock and/or equipment damage,
disconnect electrical power to the system at the main
fuse or circuit breaker until installation is complete.

Before removing wires from old thermostat’s switching subbase,

label each wire with the terminal designation it was removed from.

1. Remove Old Thermostat: A standard heat/cool thermostat

consists of three basic parts:
a. The cover, which may be either a snap-on or hinge type.
b. The base, which is removed by loosening all captive screws.
c. The switching subbase, which is removed by unscrewing

the mounting screws that hold it on the wall or adaptor plate.

2. Shut off electricity at the main fuse box until installation is
complete. Ensure that electrical power is disconnected.

3. Remove the front cover of the old thermostat. With wires still
attached, remove wall plate from the wall. If the old thermostat

has a wall mounting plate, remove the thermostat and the wall
mounting plate as an assembly.

4. Identify each wire attached to the old thermostat using the
labels enclosed with the new thermostat.

5. Disconnect the wires from the old thermostat one at a time. DO
NOT LET WIRES FALL BACK INTO THE WALL.

6. Install new thermostat using the following procedures.

WHITE-RODGERS

EMERSON ELECTRIC CO
ST. LOUIS, MISSOURI

www.white-rodgers.com

PART NO. 37-6498A

Printed in U.S.A.

0342

REMOVING OLD THERMOSTAT

3

CONTINUED FROM FIRST PAGE

ATTENTION! This product does not contain mercury. How-

ever, this product may replace a unit which contains mercury.
Do not open mercury cells. If a cell becomes damaged, do not

touch any spilled mercury. Wearing non-absorbent gloves, take
up the spilled mercury and place into a container which can be
sealed. If a cell becomes damaged, the unit should be discarded.

Mercury must not be discarded in household trash. When the unit
this product is replacing is to be discarded, place in a suitable
container and return to White-Rodgers at 2895 Harrison Street,
Batesville, AR 72501-2117 for proper disposal.

O/B Terminal Switch Selection

The O/B switch on this thermostat is factory set to “O” position.
This will accommodate the majority of heat pump applications,
which require the changeover relay to be energized in COOL. If
the thermostat you are replacing or the heat pump being installed
with this thermostat requires a “B” terminal, to energize the
changeover relay in HEAT, the O/B switch must be moved to the
“B” position.

CAUTION

!

Take care when securing and routing wires so they do
not short to adjacent terminals or rear of thermostat.
Personal injury and/or property damage may occur.

MOUNTING AND WIRING

4

WARNING

!

Do not use on circuits exceeding specified voltage.
Higher voltage will damage control and could cause
shock or fire hazard.

Do not short out terminals on gas valve or primary
control to test. Short or incorrect wiring will damage
thermostat and could cause personal injury and/or
property damage.

Thermostat installation and all components of the sys­tem shall conform to Class II circuits per NEC code.

Electric/Gas Jumper (Fan Option)

If your emergency or auxiliary system will energize the blower, then
jumper W906 on the thermostat base must be cut (see fig. 1).

If your emergency or auxiliary heat system requires that the
thermostat energize the fan circuit, do not cut jumper W906.

If you are unsure of your application, contact a qualified service
person.

°F or °C Selection

The factory default setting for temperature display is Fahrenheit.
If you want the temperature in Celsius, clip jumper W904.

Fast or Slow Cycle Selection

The factory default setting is fast cycle, which cycles 1st stage at
approximately 1.2°F and 2nd stage 0.75°F. If you prefer slow
cycle, clip jump W905. The 1st stage and 2nd stage would be

1.5°F and 1.2°F respectively.

Attach Thermostat Base to Wall

1. Remove the packing material from the thermostat. Gently pull
the cover straight off the base. Forcing or prying on the
thermostat will cause damage to the unit.

2. Connect wires beneath terminal screws on base using appro­priate wiring schematic (see figs. 2 through 4).

3. Place base over hole in wall and mark mounting hole locations
on wall using base as a template.

4. Move base out of the way. Drill mounting holes.

5. Fasten base loosely to wall, as shown in fig. 1, using two
mounting screws. Place a level against bottom of base, 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 base snugly, use plastic screw
anchors to secure subbase.

6. Push excess wire into wall and plug hole with a fire-resistant
material (such as fiberglass insulation) to prevent drafts from
affecting thermostat operation.

Battery Location

This thermostat does not require batteries to operate. The 2 “AAA”
alkaline batteries are for the thermostat to remember the pro­gramming if AC voltage is lost. If the display shows BATT when
AC power is not present, the batteries are low and should be
replaced with fresh “AAA” Energizer® alkaline batteries. To re­place the batteries, install the batteries along the top of the base
(see fig. 1). The batteries must be installed with the positive (+)
ends to the right.

Energy Management Recovery (EMR)

This thermostat is set to operate with EMR. This causes the
thermostat to start the heating or cooling system early to have
the room temperature reach the program setpoint at the time
the period is to start.

To disable EMR, clip jumper W903 (see Fig. 1).

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MOUNTING AND WIRING

4

CONTINUED FROM SECOND PAGE

Changeover

Relay*

* Changeover Relay is energized in COOL when O/B switch is in the “O” position

Changeover Relay is energized in HEAT when O/B switch is in the “B” position

** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency

SYSTEM

MONITOR

SWITCH

L

24 VAC

TRANSFORMER

Compressor

Contactor

G W2

Fan

Relay

Aux

Relay

(Stage 2)

See Note **

Emergency

E

Relay

CYO/B

Figure 2. Typical wiring diagram for single transformer systems

THERMOSTAT

R

(Class II)

SYSTEM

Hot

120 VAC

Neutral

If safety circuits are in only one of the systems, remove
the transformer of the system with NO safety circuits.

CUT AND

TAPE OFF!

HOT

120 VAC

NEUTRAL

* Changeover Relay is energized in COOL when O/B switch is in the “O” position

Changeover Relay is energized in HEAT when O/B switch is in the “B” position

** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency

24 VAC

Changeover

Relay*

Compressor

Contactor

G W2

Fan

Relay

Figure 3. Typical wiring diagram for two transformer systems with NO safety circuits

Polarity must be observed. If the HOT side of the second transformer
is jumpered to the COMMON side of the first transformer a short will
be made. Damage to equipment will occur when power is restored.

G W2

Changeover

Relay*

Compressor

Contactor

* Changeover Relay is energized in COOL when O/B switch is in the “O” position

Changeover Relay is energized in HEAT when O/B switch is in the “B” position

** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency

Fan

Relay

Aux

Relay

(Stage 2)

E

CYO/B

See Note **

Emergency

Relay

TWO COMMONS MUST
BE JUMPERED TOGETHER!

SYSTEM

MONITOR

SWITCH

Figure 4. Typical wiring diagram for two transformer systems with safety circuits in BOTH systems

NOTE

See Note **

Emergency

Aux

Relay

(Stage 2)

Relay

TWO COMMONS MUST
BE JUMPERED TOGETHER!

NOTE

L

R

COMMON

E

Limit or

Switches

Limit or

Safety

Switches

CYO/B

SYSTEM

MONITOR

SWITCH

THERMOSTAT

Safety

24 VAC

24 VAC

ACCESSORY

RELAY N.O.

CONTACT

COMMON

24 VAC 120 VAC

Heat Pump Transformer

(Class II)

L

Limit or

Switches

SYSTEM

Auxiliary

Heating

Transformer

(Class II)

THERMOSTAT

R

SYSTEM

Safety

(Class II)

Limit or

Safety

Switches

NOTE

HOT

NEUTRAL

Hot

120 VAC

Neutral

HOT

NEUTRAL

24 VAC

TRANSFORMER

120 VAC

The accessory relay scheme
is required when safety
circuits exist in both systems.

Limit or

Safety

Switches

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