Pneumatic Control Manual 717.1
Temperature Section
Technical Bulletin T-3102
Issue Date 0882
© 1982 Johnson Controls, Inc.
1
Code No. LIT-7171160X
T-3102 Heating-Cooling Deadband Thermostat
Installation and Calibration
The T-3102 is a low volume
output thermostat designed to
modulate heating and cooling
controlled devices in response to
temperature changes.
Mounting
The T-3102 can be mounted in
any position on a relatively
vibration-free surface. The
supply line must be connected to
the restricted branch of the
1/4 in. barbed tee fitting.
If a T-275-100 bulb element
holder is used to mount the
element: locate the sensitive
portion of the element in a
representative area of the air
sampling chamber. Slide the
rubber grommet on the holder
over the element past the sensing
portion. Crimp the holder slightly
to hold the element and attach
the holder to the nearest hanger.
Calibration
The T-3102 is calibrated for
4-1/2 psig and 11 psig output at
the heating and cooling set
points, respectively. This
matches the mid spring range of
typical 3 to 6 psig and 9 to
13 psig heating and cooling
valves. The 7-1/2 PSI deadband
setting falls between the spring
ranges of the two valves.
Note: On deadband
applications which have
overlapping spring ranges, a
C-9200 or other sequencing
device should be used to bias
the cooling valve spring range to
compensate for spring range
shift.
When making calibration
changes on the T-3102, always
perform the adjustments in the
following order:
1.
Deadband Adjustment
2.
Cooling Set Point
3.
Heating Set Point
Fig. 3: Factory Calibration Graph
Fig. 2: Bulb Element Mounting
