Siemens TH 192 HC, Powers TH 192 HC Technical Instructions

Powers® Controls

TH 192 HC Heating/Cooling Room
Thermostat

Technical Instructions

Document No. 155-066P25

TH 192-2

October 26, 2010

6050 70 80

70

60

TH0356R1

POWERS

80

Description

Features

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.

• 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

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 knob s.

Application

Piping

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 condit ioners,
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.

TH 192 HC

2-PIPE

THERMOSTAT

TH0256R1

R1

S

TO CONTROLLED

DEVICES

AIR SUPPLY

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 thermo stat
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.

Page 2 Siemens Industry, Inc.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010

Table 1. TH 192 HC Thermostat Chassis Part Numbers.

Chassis with Wall Plate

Fahrenheit Celsius Connection

192-207

192-208

Cooling DA

192-209

Cooling RA

192-210

Cooling DA

192-227

Cooling RA

192-228

Cooling DA

192-229

Cooling RA

192-230

— — — —

— — —

Type

Two-Pipe

Relay

Setpoint

Adjustment

Exposed

at Bottom

of Cover

Exposed

1/2” Knob

on Cover *

Heating DA Heating RA Heating DA Heating RA
Cooling DA

Cooling RA

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.

Siemens Industry, Inc. Page 3

Technical Instructions
Document Number 155-066P25
October 26, 2010

Setpoint

Adjustment

Key

(See Note 1)

Table 2. TH 192 HC Thermostat Cover Part Numbers.

Cover Configuration Cover Part Number

(See Note 2)

Setpoint

Thermometer

Concealed 192-256 192-356 Concealed

Indicator

Concealed

Exposed

Concealed 192-267 192-367

Exposed

Standard

Plastic Cover

Desert Beige

Metal Cover

Desert Beige

192-254 192-354

Exposed 192-268 192-368

Concealed 192-258 192-358 Exposed

Standard

Specifications

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.

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.

Page 4 Siemens Industry, Inc.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010

Accessories

Dimensions

Operation
Heating-Cooling

Operation

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

Figure 3. TH 192 HC Dimensions in Inches (Millimeters).

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 decrease s 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.

Document Number

155-244
155-245
155-231
155-222
155-255
155-213

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.

Siemens Industry, Inc. Page 5

Technical Instructions
Document Number 155-066P25
October 26, 2010

TH 192 HC
Thermostat Details

Figure 5. TH 192 HC Thermostat Details.

Thermometer
Calibration

Changeover Point
Adjustment

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.

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.

Page 6 Siemens Industry, Inc.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010

Changeover Point
Adjustment,
Continued

Figure 6. Changeover Point Adjustment.

Limit Stop
Adjustment

Sensitivity
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.

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)

NOTE: If the thermostat sensitivity is adjusted, the

thermostat must be recalibrated.

Graduation

closest to the

minimum

(MIN) end of

the bimetal

element
1 psi/°F

(12 kPa/°C)

Figure 8. TH 192 HC

Sensitivity Adjustment.

Siemens Industry, Inc. Page 7

Technical Instructions
Document Number 155-066P25
October 26, 2010

Thermostat
Calibration

Cooling
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.

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.

Page 8 Siemens Industry, Inc.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010

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 3 —

Moisten needle and insert 192-633 test
gauge and needle adapter in the test
port. Read control pressure.

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 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.

Siemens Industry, Inc. Page 9

Technical Instructions
Document Number 155-066P25
October 26, 2010

Troubleshooting

Figure 9. Accessing Output

Pressure Test Port.

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

Control pressure

stays at

approximately

zero

Control pressure

stays at

approximately

supply pressure

Excessive air
leakage from

exhaust port on

left side of

thermostat

Air supply

Nozzle or

flapper

Restrictor Clogged restrictor Replace restrictor

Calibration Out of calibration Recalibrate

Nozzle Clogged nozzle

Calibration

Supply and

return line

connection

Low supply

pressure

Dirt on nozzle or

flapper

Dirt on either supply

or exhaust valve

seat

Connections are

interchanged or

connection to port is

incorrect

As required

Clean nozzle or

replace thermostat

Clean nozzle or

replace thermostat

Alternately close and

open nozzle by gently

pushing down the

bimetal

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.

Page 10 Siemens Industry, Inc.

TH 192 HC Heating/Cooling Room Thermostat Technical Instructions
Document Number 155-066P25
October 26, 2010

Service Parts

Dial thermometer (-40 to 140°F, -40 to 60°C) with pocket case
Basic pneumatic calibration kit with thermometer, gauge, squeeze

bulb, fittings, and case
Test head kit 832-179
Calibration tools 832-178
Test probe to check pressure with cover on

Chassis tube connector replacement kit with mounting screws
(material for 10 thermostats included)

Restrictor plate replacement kit with filters and gasket
(material for 10 thermostats included)

Plug-in adapters for quick thermostat removal

20 scim (5.4 ml/sec) restrictors for 1-pipe systems (package of 5).
(1/4 “, 6.4 mm, OD plastic barb unless noted.)

The following chart lists accessory parts and tools available for thermostat service.

Description Part Number

141-0573

832-177

Needle probe with 1-1/2” diameter gauge 0-30 psig

192-633

(0-200 kPa) and calibration/cover wrench
Needle probe, no gauge (package of five) 192-759
1-1/2” diameter gauge , 0-200 kPa,

142-0344

back connected 1/8” NPT male
1-1/2” diameter compound gauge, 0-30 psig/0-200 kPa,

142-0373

back connected 1/8” NPT male
1-1/2” diameter compound gauge, 0-30 psig/0-200 kPa,

142-0426
bottom connected 1/8” NPT male.
Replacement for use with 192-633

192-525

192-321

Straight, blue (package of 20) 192-485
Straight, white (package of 20) 192-486
Air link connects adapters for pressure tests (package of 20) 192-501
Compression ring (package of 100) 141-388
Elbow (provides quick return for wall surface mounting), blue

192-487

(package of 20)
Elbow (provides quick return for wall surface mounting), white

192-488

(package of 20)

Brass coupling, 1/8” NPT (1 only). 184-040
Coupling 184-116
Tee 184-113
Pre-piped dual tee for dual 1-pipe systems 184-130

Siemens Industry, Inc. Page 11

Technical Instructions
Document No. 155-066P25
October 26, 2010

Service Parts
(Continued)

Description Part Number

Replacement thermometer kits, brown (packages of 5)

Scale Range Thermostat Model

45° to 85°F

192-775

10° to 30°C

TH0443R1

192-776

Model 3 and Up

45° to 85°F

192-786

10° to 30°C

TH0442R1

192-785

Models 1 and 2

Replacement setpoint dials (packages of 10)

°F, Direct Acting 192-779

°F, Reverse Acting 192-780

Right Side

°C, Direct Acting 192-783

°C, Reverse Acting

°F, Direct Acting 192-777

°F, Reverse Acting 192-778

°C, Direct Acting 192-781

Left Side

°C, Reverse Acting

192-784

192-782

Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and models as
design improvements are introduced. Powers is a registered trademark of Siemens Industry, Inc. Other product or company names mentioned
herein may be the trademarks of their respective owners. © 2010 Siemens Industry, Inc.

Siemens Industry, Inc.

Building Technologies Division
1000 Deerfield Parkway
Buffalo Grove, IL 60089-4513
USA

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Document No. 155-066P25

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