Johnson Controls T28 Installation Instructions Manual

T28 Fan Coil Thermostat

Installation Instructions T28

Issue Date 02/01/02

Application Requirements

The T28 thermostats control line voltage fan coil units
and zone valves on heating, cooling, and a
combination of heating and cooling equipment. The
thermostats directly control one or two zone valves.
Thermostats with fan switches require a two-gang
switch box at least 2 1/2 in.-deep, or a 4 in. by 4 in. or
larger junction box with a two-fixture plaster ring. For
example, use Raco No. 230 or Appleton No.4SD1/2
two-gang switch box, plus plaster ring.

Thermostats without fan switches require a 2 in.-deep
single, vertical switch box or a larger box with a
single-fixture plaster ring. For example, use Raco
No. 420 or Appleton No. 111 single switch box.

Note: The boxes and plaster rings are not included

with the thermostat.

Installation

IMPORTANT: The T28 Series Thermostats are

intended to control equipment under normal
operating conditions. Where failure or malfunction of
a T28 thermostat could lead to an abnormal
operating condition that could cause personal injury
or damage to the equipment or other property, other
devices (limit or safety controls) or systems (alarm or
supervisory systems) intended to warn of, or protect
against, failure or malfunction of the T28 thermostat
must be incorporated into and maintained as part of
the control system.

Parts Included

• thermostat

• 2 No. 6 screws

• 2 fiber washers

Note: Plaster rings and switch box are not furnished.

Mounting

Location Considerations

Mount the thermostat about 4 to 5 ft. (1.2 to 1.5 m)
above the floor on an interior wall, where it can sense
the average room temperature. Do not mount the
thermostat where it may react to heat or cold from
water pipes, windows, doors, lamps, sunlight, or other
heat or cold sources.

On unit heater applications, place the thermostat
below and behind the heater in the path of air entering
the unit—not in the path of discharge air.

To mount the thermostat:

1. Install the switch box and plaster ring (when
required). See Figure 3.

2. Remove the cooling anticipator resistor to prevent
over-anticipation on 208/240 VAC installations.
Carefully clip the left-hand resistor leads with
diagonal cutters. See Figure 3.

3. Refer to Wiring section to make the necessary
connections.

4. Loosen the cover screw at the bottom of the cover,
swing the cover bottom out, and lift up to remove.

5. Fasten the thermostat to the switch box with the
two captive screws in the baseplate.

6. Carefully remove the contact protector (insulation
barrier). See Figure 3. Move the temperature
setting lever from Cool to Warm to be sure the
contact arm is free.

7. Reposition the cover, and tighten the cover screw.

8. Turn on the power supply.

9. Check the thermostat operation. Refer to the
Checkout section.

Dimensions

Refer to Figure 1 and Figure 2 for detailed dimensions
of the T28 Fan Coil Thermostat.

© 2002 Johnson Controls, Inc.

Part No. 24-9715-0, Rev. A www.johnsoncontrols.com

1

Two Mounting Holes for Number 6 Screws

1.13
(29)

OFF

HIGH

MED

LOW

FAN

COOL

5.00

(127)

3.13
(80)

5.19

(132)

1.19
(30)

3.28
(83)

1.56
(40)

1.19

1.19
(30)

(30)

Figure 1: T28 Without Fan Switch, in. (mm)

Two Mounti ng Holes for Number 6 Screws

5.19

(132)

3.08
(78)

2.06
(52)

3.28
(83)

0.78
(20)

1.19
(30)

1.56
(40)

2.88
(73)

0.20
(5)

2.81

(71)

2.67
(68)

Figure 2: T28 with Fan Switch, in. (mm)

Cover

Mounting

Screws (2)

Figure 3: Mounting the T28 to an Outlet Box, in. (mm)

2 T28 Fan Coil Thermostat Installation Instructions

Fiber

Washer (2)

Insulation

Barrier

Cover

Screw

Two-gang

Switch Box

Plaster

Ring

(Switch Box and

Plaster Ring Not Furnished)

or

Junction

Box