Johnson Controls T-4002, T-4054, T-4003, T-4100, T-4110 Adjusting Instructions

Pneumatic Control Manual 717.1

Archived Document

Room Devices Section

T-4000 Series Room Thermostat

Adjusting Instructions*

Technical Bulletin T-4000

Issue Date 0984

The T-4000 Series Pneumatic
Room Thermostats are factory
calibrated to the values specified
in Table 1. If these settings are
suitable to the application, no
adjustments need to be made. If
different settings are required,
turn the set point dial to the
desired value.

If the room temperature is out of
control, determine the cause of
the problem. Possible causes
not involving the thermostat are
listed below.

1. Check for proper operation
of the controlled device.

*

This bulletin provides adequate instructions for making basic adjustments to
T-4000 series room thermostats. For more detailed information, contact the local
branch office.

2. Check to see if the controlled
medium (water, for example)
is hot or cold enough to
maintain the desired
temperature.

3. Check for unusual or
extreme loads in the space
which may overcome the
efforts of the thermostat to
maintain control.

If it is determined that the
thermostat is out of adjustment,
follow the appropriate instructions
to recalibrate the instrument.

Sensitivity Adjustment
(See Fig. 1)

All T-4000 series thermostats
have an integral output pressure
test port. The newer high volume
output thermostats have a plug-in
test port fitting which accepts a
hypodermic needle test probe
and gage (X-200-140 and G­2010-11). On older models, the
test port cap screw must be
removed to accept a screw-in
test gage (X-200-19). For these
units, a test port fitting (T-4000-

615) can be ordered. All low
volume output thermostats have
hypodermic needle test points.
For units that require a screw-in
gage, remember to replace the
test port cap screw after
adjustment.

The sensitivity of the T-4000
series instruments is factory set
at 2.5 PSI/F° (32 kPa/C°). It is
adjustable from 1 to 3 PSI/F
(13 to 38 kPa/C°) for low volume
output thermostats and from .
75 to 4 PSI/F° (10 to 51 kPa/C°)
for high volume output
thermostats. (Sensitivity of the T­4003 is fixed at 2.5 PSI/F°).

1. Furnish the appropriate
supply pressure to the
instrument.

2. Insert the appropriate gage.

3. Note the output pressure.

Note:

The output pressure
for T-4054 thermostats must
be within one of the two
control ranges (not within the
deadband range).

4. For high volume output
thermostats, move the
sensitivity slider toward the
control port to increase or
away from the control port to
decrease the sensitivity. For
low volume output
thermostats, move the
sensitivity slider down to

°

© 1984 Johnson Controls, Inc.

Code No. LIT-7171089X

1

increase or up to decrease

Archived Document

the sensitivity.

5. Check the output pressure.
If it is different from the value
found in step 3, turn the
sensitivity slider adjusting
screw until the output
pressure equals that value.
For low volume output
(plastic body) instruments,
use the output adjusting
screw to adjust the output
pressure.

6. Check the sensitivity.
Change the control setting
on the dial by at least 5F°
and note the new output
pressure. The change in
output pressure divided by
the change in dial setting is
the actual sensitivity.

7. Repeat steps 4 through 6
until the desired sensitivity is
obtained.

T-4003 Range of Remote
Readjustment

The range of remote
readjustment is adjustable from
.15 to 2.5 F°/PSI (.012 to
.2C°/kPa) and is factory set at

0.5 F°/PSI (.04 C°/kPa). To

determine if the range of remote
readjustment needs to be
adjusted, proceed as follows:

1. Insert the test gage into the
test port fitting and note the
output pressure.

2. Set the master pressure to
4 psig (28 kPa).

3. Turn the set point dial to 80F
and turn the calibration
screw to obtain a 3 psig
(21 kPa) output pressure.

4. Set the master pressure to
14 psig (98 kPa).

5. Turn the set point dial until
the output pressure returns
to 3 psig.

6. The change in dial setting
divided by the 10 psig
(70 kPa) change in master
pressure (14 psig - 4 psig =
10 psig) is the actual range
of readjustment. If this is not
the desired range, move the
range of readjustment slider
(sensitivity slider in Fig. 1a)
toward the control port to
decrease or away from the
control port to increase the
range of readjustment.
Readjust the slider screw to
the pressure noted in step 1
above. Repeat steps 2
through 6 until the desired
range is obtained.

Set Point Adjustment

Before calibrating the instrument,
check to see if the output
pressure is already at an
appropriate value according to
the ambient temperature. For

example, if the actual room
temperature is below the set
point and the output signal is
calling for more heat, the
thermostat is doing its job and
does not require adjustment.

T-4002 and T-4100 (See Fig. 1)

1. Insert the test gage.

2. Furnish supply air to the
instrument (restricted supply
for T-4100).

3. Note the ambient
temperature in the space.

4. Turn the set point dial to that
temperature.

5. Turn the calibration screw
until the output pressure is at
the mid spring range of the
controlled device.

6. Turn the set point dial to the
desired set point.

T-4003 Set Point Adjustment

Insert the gage and set the
master pressure to one half of
the supply pressure. Follow
steps 3 through 6 under T-4002
Set Point Adjustment.

2 T-4000 Technical Bulletin

Fig. 2: T-4054 Adjustments

Archived Document

Fig. 3: Back View of T-4054

T-4054 Deadband and Set
Point Adjustment
(See Fig. 2)

The T-4054 can easily be
adjusted to suit the application by
changing the settings on the
heating and cooling dials. If the
thermostat has been tampered
with or is out of adjustment,
proceed with the following
instructions to recalibrate the
instrument.

Note: On deadband applications
which have overlapping spring
ranges, it is suggested that a
C-9200 or other sequencing
device be used to bias the
cooling valve spring range to
compensate for spring range
shift.

Deadband Setting

If it is necessary to check or reset
the deadband setting, proceed as
follows:

Turn the lower set point dial to 85F
on direct acting models or 55F on
reverse acting models. Turn the
upper set point dial to 55F on direct
acting models or 85F on reverse
acting models. Insert a hypodermic
needle test probe into the test
connection. The reading on the test
gage is the actual deadband
pressure.

If it is necessary to adjust this
pressure to meet application
requirements, proceed as follows:

1. Remove the T-4054 from the
mounting bracket and pull it
away from the wall so the
deadband adjusting screw
on the back of the instrument
is exposed (see Fig. 3).

2. Turn the screw clockwise to
increase or counter­clockwise to decrease the
deadband pressure until the
gage reads the desired
pressure. Approximately
one half turn will produce a
1 PSI (7 kPa) change in
deadband pressure.

3. Return the set point dials to
the original settings.

Set Point Calibration
(See Fig. 2)

1. Set the lower set point dial to
85F for direct or 55F for
reverse acting models.

2. Note the ambient
temperature at the element.

3. Set the upper dial to this
temperature (direct acting
model: heating, reverse
acting model: cooling).

4. Turn the upper calibration
screw until the control
pressure is in the middle of
the spring range of the
controlled device (heating).

5. Set the lower dial to the
temperature noted in step 2
(direct acting model:
cooling, reverse model:
heating).

6. Turn the lower calibration
screw until the control
pressure is in the middle of
the spring range of the
controlled device (cooling).

7. Turn the upper dial to the
desired set point.

T-4054 Operational Graph

T-4000 Technical Bulletin 3