Install Instructions

Copyright 2008, TAC
All brand names, trademarks and registered
trademarks are the property of their respective
owners. Information contained within this
document is subject to change without notice.
F-27495-3
www.tac.com
TAC
1354 Clifford Avenue
P.O. Box 2940
Loves Park, IL 61132-2940
Locate the thermostat where it will be exposed to an
unrestricted circulation of air, which represents the average
temperature of the controlled space.
Installation
• Tools (not provided):
– Appropriate screwdriver for mounting the thermostat
– 20-881 Thermostat calibration and cover screw
wrench (or 1/16" and 1/4" hex wrenches)
Figure-2
1. Assemble the eyelets and two tube couplers to tubing.
2. Connect the assembly by inserting the tube couplers into
existing tubing in the wall (Figure-2). Note which
connection is Main and which connection is Branch.
3. Pull tubing through center hole in mounting plate and
screw mounting plate to wall with flat head screws. Cut
tubing and insert two couplers. The Main and Branch
tubing is connected into the corresponding ports on the
thermostat (Figure-1).
4. Affix thermostat to mounting ring with round head
screws, taking care not to kink the tubing.
Calibration and Throttling Range Setting
The thermostats are factory calibrated and are shipped with
the throttling range set at 3 °F. They should not require
calibration upon installation. However, if it is necessary,
change the calibration or throttling range setting as follows:
1. Remove the thermostat cover, using a 20-881 thermostat
wrench (1/16" hex wrench), and install a 22-138 branch
tap gauge adaptor into the branch pressure tap hole.
2. Measure the ambient temperature with an accurate
thermometer. This temperature
must be within the range
of the thermostat
.
3. Move the setpoint adjustment to the measured ambient
temperature, using the internal setpoint indicator.
Connect to
Main and Branch
Connect to Thermostat
Main and Branch
4 Eyelet
Tube Clamps
Eyelet
Tube Coupler
Tubing
Eyelet
Tube Coupler
4. Taking care not to breathe on, or place the hand near the
bimetal, use a 20-881 thermostat wrench (1/16” hex
wrench) to turn the calibration screw until the branch line
pressure indicates 9 psig. Clockwise rotation increases
the branch line pressure. Counterclockwise rotation
lowers the branch line pressure.
5. Reinstall the thermostat cover and set the thermostat to
the desired setpoint.
Dimensional Data
˚F ˚C
5
2
12
6
2
T R
H
Internal Setpoint
Indicator
Branch
Pressure
Tap
Setpoint Adjustment
Thermostatic
Bimetal
Calibration
Screw
Cover Scale
Setpont Indicator
Celsius
Scale
Fahrenheit
Scale
Limit Stops (2)
(Accessory)
1-1/4
(3.18)
1-3/8
(3.5)
1/8
(.318)
1-3/8
(3.5)
2-1/32
(5.16)
2-1/32
(5.16)
MB
Dimensions are in inches (mm).