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RAB20 Series
Two-pipe Fan Coil Room
Thermostat with Automatic
Changeover
Description
Features
Application
Product Numbers
Accessory
Technical Design
Two-wire, gas diaphragm-based fan coil room thermostat for heating or cooling
systems with two-pipe fan coil applications.
•
Automatic changeover
•
Manual, three-speed fan switch
•
Fan release function
•
Dual setpoint temperature scale
•
Two-point control algorithm (On/Off)
•
24 to120 Vac, 277 Vac operating voltage
•
Two mounting styles: electrical wall box or drywall
•
Wall plate adapter (ARG70) included with electrical wall box mount styles
The RAB20... is used in heating or cooling systems with external automatic
changeover devices (aquastats) to maintain the selected room temperature.
Typically used in commercial, high-rise and light industrial buildings in conjunction with:
•
Zone valves
•
Thermal valves
•
Fans
•
Aqua sensors (changeover sensors, provided by others)
See Table 1.
ARG70 Wall box adapter
The RAB20... fan coil room thermostat is based on a two-wire, gas diaphragm
technology.
Technical Instructions
Document No. 155-526P25
RAB20.1
Siemens Building Technologies, Inc.
ET RAB-2
March 2, 2007
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Table of Contents
Related Manuals for Siemens RAB20 Series
Summary of Contents for Siemens RAB20 Series
- Page 1 • Fans • Aqua sensors (changeover sensors, provided by others) Product Numbers See Table 1. Accessory ARG70 Wall box adapter Technical Design The RAB20… fan coil room thermostat is based on a two-wire, gas diaphragm technology. Siemens Building Technologies, Inc.
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Page 2: Operation
Technical Instructions RAB20 Series Two-pipe Fan Coil Room Thermostat Document Number 155-526P25 March 2, 2007 Operation If the room temperature falls below the selected setpoint, the heating contact is closed. Heating Mode Cooling Mode If the room temperature rises over the selected setpoint, the cooling contact is closed. -
Page 3: Warning/Caution Notations
RAB20 Series Two-pipe Fan Coil Room Thermostat Technical Instructions Document Number 155-526P25 March 2, 2007 Warning/Caution Notations WARNING: Personal injury, or loss of life may occur if you do not perform a procedure as specified. Operating voltage 24 to 120 Vac, 277 Vac... -
Page 4: Installation
Technical Instructions RAB20 Series Two-pipe Fan Coil Room Thermostat Document Number 155-526P25 March 2, 2007 Mounting Locate the unit where the air temperature can be sensed as accurately as possible. Do not mount in direct sunlight or near other heat or refrigeration sources. - Page 5 RAB20 Series Two-pipe Fan Coil Room Thermostat Technical Instructions Document Number 155-526P25 March 2, 2007 Drywall Mounting 1. Loosen the two screws at the bottom of thermostat. 2. Lift the bottom of the thermostat cover from the thermostat base and push up to remove cover.
- Page 6 Technical Instructions RAB20 Series Two-pipe Fan Coil Room Thermostat Document Number 155-526P25 March 2, 2007 4 × 4-inch Electrical Wall An ARG70 wall plate adapter (provided with electrical wall box mount models) is Box Mounting required to mount an RAB… thermostat to a 4 × 4-inch electrical wall box.
- Page 7 RAB20 Series Two-pipe Fan Coil Room Thermostat Technical Instructions Document Number 155-526P25 March 2, 2007 2 × 4-inch Electrical Wall An ARG70 wall plate adapter (provided with electrical wall box mount models) is Box Mounting required to mount an RAB… thermostat to a 2 × 4-inch electrical wall box.
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Page 8: Maintenance
Technical Instructions RAB20 Series Two-pipe Fan Coil Room Thermostat Document Number 155-526P25 March 2, 2007 Maintenance The room thermostat is completely maintenance-free. If inoperable, replace entire unit. WARNING: High voltage. Disconnect power before servicing. Metal part is not grounded. Aqua sensor (by others) - Page 9 RAB20 Series Two-pipe Fan Coil Room Thermostat Technical Instructions Document Number 155-526P25 March 2, 2007 Dimensions Ø 0.25 (6.4) Dimensions in inches Ø 0.14 (3.6) (millimeters) 3.80 1.68 0.66 (96.4) (42.8) (16.9) 1.00 1.18 (25.5) (30) 3.38 (86) Figure 7. RAB20… Unit.