Honeywell TH150 User Manual

1. Introduction

The TH150 Series electronic thermostat is designed for low-voltage
pressure-dependent variable air volume (VAV) applications. It
comes in four different models:

TH150 Series

Installation and User Guide

VAV Thermostat

• TH150-1A • TH150-1F

• TH150-1A2T • TH150-1F2T

Depending on the model, the TH150 thermostat can have up to
three outputs connected to the following control devices:

 actuators
 thermal valves (N.O. and N.C.)
 solenoid valves
 solid-state relays (SSRs)
 silicon-controlled rectifiers (SCRs)
 mechanical relays
 contactors

Accessories

 RC840 or RC840T electromechanical relay
 RT850 or RT850T solid-state relay
 AC146-410 temperature sensor
 AC144-03 temperature sensor

2. Installation

2.1 Mounting Instructions

n Remove the thermostat from its base by unscrewing the cap-

tive screw and tilting the bottom of the thermostat up. The
screw cannot be completely removed.

Configuration and status display

Heating mode

Cooling mode

Temperature
adjustment
button

Override button

Temperature display

Output power display

2.2 Terminal Designations

The designations of the terminals vary according to the particular
model of thermostat. Refer to the following table for the description
of each terminal.

TERMINAL DESCRIPTION

1224 VAC

COM

34AN1

COM

34OPEN

CLOSED

56T2/AN2

T2/COM

78T3

T3

910COM

o Pass the wires through the center hole of the base and secure

the base to the wall or onto an electrical box.

p Wire the thermostat. See section 2.2 for terminal designations

and section 3 for typical wiring diagrams.

q Reinstall the thermostat onto its base and secure with the cap-

tive screw.

TH150 400-150-000-C 5/9/06 1/6

SENSOR

911COM

C-Over

912COM

NSB

Note: To configure the terminals, see section 4.

Power supply

Models TH150-1A and TH150-1A2T

Output 1

Models TH150-1F and TH150-1F2T

Output 2 (models TH150-1A2T and TH150-1F2T)

Output 3 (models TH150-1A2T and TH150-1F2T)

External sensor input. (For applications requiring
an external sensor, see section 4.2.)

Mode Changeover input (N.O. contact). See sec­tion 5.5.2.

Night Setback activation input (N.O. contact).
See section 5.6.

3. Typical Applications

FIGURE 1: Damper control with electric reheat and auxiliary
baseboard heating.

FIGURE 3: Damper control with automatic changeover, elec­tric reheat and central cooling

FIGURE 2: Damper control with electric reheat and auxiliary
hot-water heating

FIGURE 4: Temperature control of fresh air supply

CAUTION

Do not connect
common to ground

FIGURE 5: Changeover and NSB inputs sharing the same
24-Vac transformer

TH150 400-150-000-C 5/9/06 2/6

FIGURE 6: Changeover and NSB inputs using different 24-Vac
transformers

CAUTION

Do not connect com­mon to ground