Brochure

8 T-3100, T-3200, and T-3300 Series Controllers Product/Technical Bulletin
Averaging Element
In most cases, an averaging element will be installed in the
air chamber of the terminal air unit in the following manner:
1. Install the element in a serpentine fashion across the top
of the unit coil.
2. Secure the element along the entire length by using
holders, T-275-101 (ordered separately), so that no part
of the element touches the coil. The holder is very
flexible and can be bent to any desired position.
3. On face and bypass units, the element must be placed in
the space where a mixing of coil discharge air (face)
and coil bypass air takes place. Install the element as
close as possible to the bottom side of the discharge air
grille. The element should be secured by using holders
(T-275-101, ordered separately) fastened to the unit
casing.
For ASHRAE Cycle III applications, the element must
be installed in the mixed air (outside and return) rather
than in the discharge air. Install the element so it will
receive the best possible sampling of the mixture
temperature using holders (T-275-101, ordered
separately) fastened to the unit casing.
Slip pron
g
s
over coil fin.
Twist here
if required.
Bend pron
g
s around
bulb or capillary.
3/16
5
2-1/4
57
1
25
Coil Fin
Figure 12: Averaging Element Holder Dimensions,
in./mm (T-275-101, ordered separately)
C
alibration Procedures
All Johnson Controls instruments are carefully tested and
calibrated at the factory before shipment. If field calibration
is required, it should not be started until all installation
procedures are complete. If, during calibration, the
temperature at the measuring element fluctuates, place the
element in a stable, well-controlled temperature area such as
a bucket of water, preferably 75°F (24°C) for controllers and
56°F (13°C) for low limit controllers.
Be sure the supply air to the instrument is clean and free of
moisture. The adjusting dial is graduated in
1F° increments and can be removed with a flexible
hex head screwdriver (JC 5309, ordered separately). It is
recommended that the middle graduation be used to
represent the desired temperature setpoint.
The adjusting screw for externally adjusted,
Direct Acting (DIR) models is located inside the dial post
and is accessible by removing the dial (refer to Figure 13,
Detail A). For DIR models with concealed adjustment, it is
necessary to remove the small metal button in the cover
(refer to Figure 13, Detail B). A calibration tool (T-4002-
5009, ordered separately) should be used to adjust the
setpoint on these models.
It is necessary to remove the dial and cover for models with
either Reverse Acting (REV) or low limit adjustments. Use
a calibration tool (T-4002-5009, ordered separately) for
Reverse Acting adjustment of the T-3100 and T-3300 Series
Thermostats (refer to Figure 13, Detail C).
Be sure each T-3100 and T-3111 Thermostat has a 0.007
inch in-line restrictor installed in the supply air connection.
The T-3200 instruments should have a 0.007 inch in-line
restrictor in the air line between the instrument and the room
thermostat.