Siemens TH 192 HC Owner's manual

Powers®Controls
Technical Instructions
Document No. 155-066P25
TH 192-2
October 26, 2010
TH 192 HC Heating/Cooling Room
Thermostat
80
60
70
TH0356R1
POWERS
6050 70 80
Description The TH 192 HC thermostats are proportional single output, dual setpoint, 2-pipe (high
air capacity) sensor controllers. Each thermostat includes a wall mounting plate for
installation in a variety of rough-in terminal boxes. Sensitive bimetals respond to
temperature change to modulate control air through a flapper nozzle. Two setpoint dials
are provided. When the supply air pressure changes from 18 to 25 psi (124 to 172
kPa), the thermostat automatically switches from the cooling to the heating setpoint
respectively. Air connections are made with 5/32” (4 mm) O.D. plastic tubing, directly to
the thermostat chassis for retrofit applications or with plug-in adapters (provided with
the TH 192 rough-in terminal box or optional accessories) which slide into the wall
mounting plate.
Features •Direct and reverse acting models for heating and cooling modes.
•Separate adjustable temperature setpoint indicating dials for heating and cooling.
•Fahrenheit or Celsius setpoint dials.
•Highly sensitive bimetal thermostatic element.
•Individual field adjustable sensitivity with graduated scale.
•Operating mode automatically switches between heating and cooling on change of
main air supply pressure.
•Integral field adjustable limit stops.
•Control pressure test port accessible without removing cover.
•Easily replaceable thermometer, setpoint dials, filters, and restrictor plate.
•Covers available for concealed or exposed thermometers and for either concealed,
key, or exposed knob adjustment and setpoint indication.
•Standard plastic thermostat covers provide Desert Beige or white finish.
Siemens Industry, Inc.

Technical Instructions
Document Number 155-066P25
October 26, 2010
Page 2 Siemens Industry, Inc.
Optional Design
Features
•Fixed temperature limit stops meet government specifications.
•Metal covers available in standard configurations provide Desert Beige or white
finish.
•Competitor adapter mounting kits available.
•All thermostat chassis available with optional 1/2” large setpoint adjustment knobs.
Application TH 192 HC thermostats provide all-season temperature control for two-pipe hot
water/chilled water heating and cooling applications (Figure 1) such as air conditioners,
space heaters, and unit ventilators. Thermostats maintain energy management
(maximum economy) and occupant comfort automatically as seasons change from the
heating setpoint (65-68°F, 10-20°C) to the cooling setpoint (76-80°F, 24-27°C).
TH 192 HC thermostats are available with covers that conceal or expose the setpoint
adjustment dials.
Figure 1. Typical TH 192 HC Thermostat Application.
Piping
TO CONTROLLED
DEVICES
AIR SUPPLY
R1
S
TH 192 HC
2-PIPE
THERMOSTAT
TH0256R1
Figure 2. TH 192 HC Thermostat Connections.
Product Numbers
and Ordering
Information
Chassis
See Table 1 for product number and ordering information on TH 192 HC thermostat
chassis.
1. Is a Fahrenheit or Celsius scale required?
2. Is the heating control direct or reverse acting?
3. Is the cooling control direct or reverse acting
4. Where is setpoint adjustment knob located?
a. Adjustment knob located at bottom of chassis.
b. Adjustment knob on front with 1/2” large exposed knob.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010
Siemens Industry, Inc. Page 3
Table 1. TH 192 HC Thermostat Chassis Part Numbers.
Chassis with Wall Plate
Fahrenheit CelsiusConnection
Type Setpoint Adjustment Heating DA Heating RA Heating DA Heating RA
Cooling DA
192-207 Cooling DA 192-209 Cooling DA 192-227 Cooling DA 192-229
Exposed
at Bottom
of Cover Cooling RA
192-208 Cooling RA 192-210 Cooling RA 192-228 Cooling RA 192-230
— — — —
Two-Pipe
Relay
Exposed
1/2” Knob
on Cover * Cooling RA
192-208 K — — —
* This feature requires a key setpoint adjustment cover (or key type cover).
See Table 2.
Covers See Table 2 for product number and ordering information on TH 192 HC thermostat
covers.
1. Is the setpoint adjustment exposed for customer adjustment or concealed to
prevent alteration of setting?
2. Is the thermometer exposed or concealed?
3. Is the setpoint indication exposed or concealed behind cover?
4. Is a plastic or zinc cast metal cover required?
a. Plastic covers order 192-2XX.
b. Metal covers order 192-3XX.
5. Is finish of cover standard or optional? The standard finish color for plastic and
metal covers is Desert Beige.
a. For white plastic cover option, add “W” suffix code to cover part number
(for example: 192-256W). See Table 2.
b. For white metal cover option, add "H" suffix code to cover part
(for example: 192-356H). See Table 2.

Technical Instructions
Document Number 155-066P25
October 26, 2010
Page 4 Siemens Industry, Inc.
Table 2. TH 192 HC Thermostat Cover Part Numbers.
Cover Configuration Cover Part Number
(See Note 2)
Setpoint
Adjustment Thermometer Setpoint
Indicator Standard Plastic Cover
Desert Beige
Standard
Metal Cover
Desert Beige
Concealed 192-256 192-356Concealed Exposed Concealed 192-254 192-354
Concealed 192-267 192-367
Key
(See Note 1) Exposed 192-268 192-368
Concealed 192-258 192-358Exposed
Exposed
Exposed
192-260 192-360
1. Key setpoint adjustment cover required for all thermostat chassis with
optional 1/2” large setpoint adjustment knobs.
2. To order a plastic cover with white finish, add the "W" suffix code. To order a
metal cover with a white finish, add the "H" suffix code.
Specifications Control action See Table 1.
Operating ranges 45 to 85°F (7 to 30°C)
Supply air pressure, maximum 30 psi (207 kPa)
Normal air supply pressure
Heating 25 psi (172 kPa)
Cooling 18 psi (124 kPa)
Sensitivity adjustment 1 to 4 psi/°F (12 to 50 kPa/°C)
Nominal air consumption (two-pipe) 25 scim (6.8 ml/sec)
Temperature
Storage temperature -10 to 140°F (-23 to 60°C)
Ambient operating temperature 40 to 140°F (4 to 60°C)
Temperature response 0.1°F (0.06°C)
Dial graduations 2°F (1°C)
Factory settings
Calibration @ 72°F (22°C) 7.5 psi (52 kPa)
Sensitivity 2.5 psi/°F (31 kPa/°C)
Limit stop adjustment 45 and 85°F (7 and 30°C)
Standard cover Cycolac, Desert Beige
Shipping weight 0.7 lbs. (0.3 kg)
Dimensions See Figure 3.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010
Siemens Industry, Inc. Page 5
Accessories See the following Technical Bulletins for information on accessories.
Technical Bulletin
TB 237 Terminal Kits
TB 213 Aspirator Wall Box Kit
TB 214 Adapter Kits
TB 193 Guard Kit
TB 241 Test Head Kit
TB 167 Restrictors
Document Number
155-244
155-245
155-231
155-222
155-255
155-213
Dimensions
Figure 3. TH 192 HC Dimensions in Inches (Millimeters).
Operation
Heating-Cooling
Operation
The TH 192 HC thermostat combines direct or reverse acting heating control with direct
or reverse acting cooling control. In direct acting control, an increase in temperature
increases the control air pressure and a decrease in temperature decreases the control
pressure. In reverse acting control, an increase in temperature decreases the control air
pressure and a decrease in temperature increases the control pressure.
The TH 192 HC provides two separate bimetal elements; one for heating mode control
and one for cooling mode control. Each bimetal element operates independently of the
other. Use of two different supply air pressures accomplishes changeover from heating
to cooling modes. A supply pressure of 18 psi (124 kPa) or 25 psi (172 kPa) positions a
changeover switch so a changeover relay operates in the cooling or heating mode
respectively.
Figure 4. TH 192 HC Input/Output Characteristics.

Technical Instructions
Document Number 155-066P25
October 26, 2010
Page 6 Siemens Industry, Inc.
TH 192 HC
Thermostat Details
Figure 5. TH 192 HC Thermostat Details.
Thermometer
Calibration 1. Use a test thermometer to read the current room temperature.
2. Place a screwdriver in the center of the thermometer assembly (Figure 5). Carefully
rotate thermometer assembly until pointer tip indicates the correct room temperature.
NOTE: Avoid breathing on or touching the bimetal spiral since this influences the
temperature reading.
Changeover Point
Adjustment The changeover point is factory set to occur between 19 and 22 psi (131 and 152 kPa). The
changeover point can be field adjustable to occur between 14 and 22 psi (96 and 152 kPa).
1. Connect pressure gauge or manometer to measure supply pressure to thermostat. Use
30 psi (207 kPa) supply through a positioning switch so pressure can be fully variable.
2. Determine current change over point. Turn cooling dial so cooling and heating control
pressures are different. Then note the changeover point on the control gauge as the
supply pressure changes.
3. Remove thermometer for access to changeover adjustment screw. Use a 1/16’ Allen
Hex Key to adjust changeover adjustment screw as follows:
a. If changeover is too high, turn off supply pressure and rotate changeover
adjustment screw clockwise. One turn decreases changeover point by about 3 psi
(20 kPa). Turn on supply pressure and recheck to verify new changeover point.
b. If changeover is too low, turn off supply pressure and rotate changeover
adjustment screw counterclockwise. One turn increases changeover point by
about 3 psi (20 kPa). Turn on supply pressure and recheck to verify new
changeover point.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010
Siemens Industry, Inc. Page 7
Changeover Point
Adjustment,
Continued
Figure 6. Changeover Point Adjustment.
Limit Stop
Adjustment Thermostat limit stops define the
minimum and maximum thermostat
setpoints. The limit stops engage in the
setpoint cam gear teeth and cause
interference between the setpoint cam
gear and the adjustment knob gear.
To change limit stop settings, use needle
nose pliers to pull limit stop between the
setpoint cam gear teeth. Rotate limit
stop to its new position. Do not pull limit
stop any more than necessary to clear
the gear teeth. Changing the limit stop
position one gear tooth changes the limit
stop setting by 1-1/3°F (0.7°C).
Figure 7. TH 192 HC Limit Stop Adjustments.
Sensitivity
Adjustment To change thermostat sensitivity, use a flat blade
screwdriver to carefully move the sensitivity slide to
the desired position as follows:
Graduation
closest to the
rigid end of the
bimetal element
4 psi/°F
(50 kPa/°C)
Graduation
closest to the
minimum
(MIN) end of
the bimetal
element
1 psi/°F
(12 kPa/°C)
NOTE: If the thermostat sensitivity is adjusted, the
thermostat must be recalibrated.
Figure 8. TH 192 HC
Sensitivity Adjustment.

Technical Instructions
Document Number 155-066P25
October 26, 2010
Page 8 Siemens Industry, Inc.
Thermostat
Calibration The thermostat is factory calibrated to a control pressure of 7.5 psi (52 kPa) when the
setpoint and the ambient temperature are both at 72°F (22°C). The factory sensitivity setting
is approximately 2.5 psi/°F (31 kPa/°C). No adjustments are required if these settings are
appropriate for the application. If the thermostat has been tampered, the sensitivity
changed, or is out of adjustment, use the following steps to re-calibrate the instrument.
Cooling
Calibration
Step 1 —
Remove cover using 192-632
calibration tool. Verify room
temperature is between 70 and 80°F
(21 and 27°C).
Step 2 —
Verify that supply pressure is 18 psi (124 kPa).
Set cooling dial to room temperature by turning
the exposed adjustment knob or using a hex key
as shown. Allow thermostat to stand for about five
minutes to adjust to the new setting.
Step 3 —
Moisten needle and insert 192-633 test
gauge and needle adapter in the test
port. Read control pressure.
Step 4 —
If control pressure does not read 7 to 8 psi (48 to
55 kPa), turn calibration screw using 192-632
calibration tool or 1/8” (3.2 mm) wrench until
pressure is 7 to 8 psi (48 to 55 kPa). The sensing
element is now in calibration and the setpoint can
be changed to the desired room temperature.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010
Siemens Industry, Inc. Page 9
Heating
Calibration
Step 1 —
If not already done, remove cover using
192-632 calibration tool. Verify room
temperature is between 70 and 80°F
(21 and 27°C).
Step 2 —
Verify that supply pressure is 25 psi (172 kPa).
Set heating dial to room temperature by turning
the exposed adjustment knob or using a hex key
as shown. Allow thermostat to stand for about five
minutes to adjust to the new setting.
Step 3 —
Moisten needle and insert 192-633 test
gauge and needle adapter in the test
port. Read control pressure.
Step 4 —
If control pressure does not read 7 to 8 psi (48 to
55 kPa), turn calibration screw using 192-632
calibration tool or 1/8” (3.2 mm) wrench until
pressure is 7 to 8 psi (48 to 55 kPa). The sensing
element is now in calibration and the setpoint can
be changed to the desired room temperature.

Technical Instructions
Document Number 155-066P25
October 26, 2010
Page 10 Siemens Industry, Inc.
Troubleshooting Before troubleshooting thermostat per Table 4, make certain there is clean dry supply air
at 18 psi (124 kPa) for cooling and 25 psi (172 kPa) for heating. Use test probe gauge
and needle adapter to measure control pressure at thermostat test port.
The output pressure test port is accessible without removing the thermostat cover
through the 8th opening from the top left side for two-pipe thermostats.
Table 3. Troubleshooting Guide.
Problem Check Cause Action
Air supply Low supply
pressure As required
Nozzle or
flapper Dirt on nozzle or flapper Clean nozzle or replace thermostat
Restrictor Clogged restrictor Replace restrictor
Control pressure
stays at
approximately
zero
Calibration Out of calibration Recalibrate
Nozzle Clogged nozzle
Clean nozzle or
replace thermostat
Control pressure
stays at
approximately
supply pressure Calibration Dirt on either supply
or exhaust valve
seat
Alternately close and
open nozzle by gently
pushing down the
bimetal
Figure 9. Accessing Output
Pressure Test Port.
Excessive air
leakage from
exhaust port on
left side of
thermostat
Supply and
return line
connection
Connections are
interchanged or
connection to port is
incorrect
As required
Chassis Tube
Connector and
Restrictor Plate
Replacement
1. Remove thermostat chassis from wall. Terminal does not have a ball check valve.
NOTE: You must close off the supply air. For example, use a connector with the supply air
terminal plugged.
2. Remove two Phillips head screws from connector on back of thermostat chassis. Pull
connector out of recess. If necessary, pry connector loose with a screw driver, but be
careful not to damage restrictor plate and gasket.
3. Remove gasket from under connector. Remove restrictor. Remove second gasket from
under restrictor.
4. Use restrictor replacement kit 192-321 to replace gasket, restrictor, and second gasket.
NOTE: The restrictor plate is keyed to ensure proper orientation during installation.
5. Remove filters from existing connector and insert in new connector. Or, if filters are
dirty, use restrictor replacement kit 192-321 to replace filters.
6. Use chassis tube connector replacement kit 192-525 to replace connector and mounting
screws.