AMX ENV-VST-C User manual

INSTRUCTION MANUAL
VIEWSTAT COLOR COMMUNICATING THERMOSTAT
ENV-VST-C

IMPORTANT SAFETY INSTRUCTIONS
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means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of AMX. Copyright protection claimed
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LIABILITY NOTICE
No patent liability is assumed with respect to the use of information contained herein. While every precaution has been taken in the preparation of this
publication, AMX assumes no responsibility for error or omissions. No liability is assumed for damages resulting from the use of the information
contained herein. Further, this publication and features described herein are subject to change without notice.
AMX WARRANTY AND RETURN POLICY
The AMX Warranty and Return Policy and related documents can be viewed/downloaded at www.amx.com.
1. READ these instructions.
2. KEEP these instructions.
3. HEED all warnings.
4. FOLLOW all instructions.
5. DO NOT use this apparatus near water.
6. CLEAN ONLY with dry cloth.
7. DO NOT block any ventilation openings. Install in accordance with the manufacturer's instructions.
8. DO NOT install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that
produce heat.
9. DO NOT defeat the safety purpose of the polarized or grounding type plug. A polarized plug has two blades with one wider than the
other. A grounding type plug has two blades and a third grounding prong. The wider blade or the third prong are provided for your
safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
10. PROTECT the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the point where
they exit from the apparatus.
11. ONLY USE attachments/accessories specified by the manufacturer.
12. USE ONLY with a cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is
used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13. UNPLUG this apparatus during lightning storms or when unused for long periods of time.
14. REFER all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as
power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been
exposed to rain or moisture, does not operate normally, or has been dropped.
15. DO NOT expose this apparatus to dripping or splashing and ensure that no objects filled with liquids, such as vases, are placed on
the apparatus.
16. To completely disconnect this apparatus from the AC Mains, disconnect the power supply cord plug from the AC receptacle.
17. Where the mains plug or an appliance coupler is used as the disconnect device, the disconnect device shall remain readily operable.
18. DO NOT overload wall outlets or extension cords beyond their rated capacity as this can cause electric shock or fire.
The exclamation point, within an equilateral triangle, is intended to alert the user to the presence of important operating and maintenance
(servicing) instructions in the literature accompanying the product.
The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated "dangerous
voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electrical shock to persons.
ESD Warning: The icon to the left indicates text regarding potential danger associated with the discharge of static electricity from an outside
source (such as human hands) into an integrated circuit, often resulting in damage to the circuit.
WARNING: To reduce the risk of fire or electrical shock, do not expose this apparatus to rain or moisture.
WARNING: No naked flame sources - such as lighted candles - should be placed on the product.
WARNING: Equipment shall be connected to a MAINS socket outlet with a protective earthing connection.
WARNING: To reduce the risk of electric shock, grounding of the center pin of this plug must be maintained.

Table o f Contents
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ENV-VST-C - Instruction Manual
Table of Contents
ENV-VST-C ViewStat Color Communicating Thermostat ..................................7
Overview ........................................................................................................................... 7
System Components ........................................................................................................ 7
Installation and Wiring .....................................................................................9
Overview ............................................................................................................................ 9
Disconnecting Power to All HVAC Equipment ................................................................... 9
Selecting the Thermostat Location ................................................................................... 9
Stand-Alone Thermostat Mounting Criteria ........................................................................................... 9
Remote Temperature Sensors................................................................................................................ 9
Removing the Faceplate from the Base.................................................................................................. 9
Mounting the Base to a Wall ................................................................................................................... 9
Wiring the Thermostat ................................................................................................... 10
Wiring Terminals................................................................................................................................... 10
Communication and Equipment Terminal Wiring Definitions .............................................................. 11
Preparing Captive Wires ....................................................................................................................... 11
Wiring Guidelines.................................................................................................................................. 11
Wiring for AxLink .................................................................................................................................. 11
Wiring Diagrams ............................................................................................................. 12
Single Stage Furnace and Single Stage A/C......................................................................................... 12
Dual Stage Furnace and Dual Stage A/C .............................................................................................. 12
Roof Top Unit with Dual Stage Heat and Dual Stage Cool .................................................................... 13
Boiler and A/C with Separate Transformers ........................................................................................ 13
Single Stage Heat Pump ....................................................................................................................... 14
Two Stage Heat Pump........................................................................................................................... 15
First Stage Radiant Floor Heat, Second Stage Furnace with Single Stage Cooling ............................. 16
Installing a Remote Sensor ............................................................................................ 16
Installing the Outdoor Temperature Sensor ........................................................................................ 17
Installing the Indoor Flush Mount Sensor............................................................................................ 17
Setup and Configuration .................................................................................19
Overview ......................................................................................................................... 19
Front Panel Components................................................................................................ 19
Display .................................................................................................................................................. 19
Navigation Buttons ............................................................................................................................... 19
Mode/Select Button.............................................................................................................................. 19
Navigating the ViewStat Color Communicating Thermostat ......................................... 19
Main Screen .......................................................................................................................................... 19
Changing the Heating and Cooling Setpoints ...................................................................................... 20
Changing Hold Mode............................................................................................................................. 20
Changing the Heating/Cooling Mode ................................................................................................... 21

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Turning Off the HVAC System ............................................................................................................... 21
Changing the Fan Mode ........................................................................................................................ 22
Help Screen........................................................................................................................................... 22
Current Weather Screen....................................................................................................................... 23
5-Day Forecast Screen.......................................................................................................................... 23
Thermostat Mode Screen ..................................................................................................................... 24
Program Screen .................................................................................................................................... 24
Establishing Daytime/Nighttime Temperature Settings ...................................................................... 25
Copying Programmed Settings ............................................................................................................ 25
Away Mode Screen ............................................................................................................................... 26
Establishing Away Mode Settings......................................................................................................... 26
Settings Screen..................................................................................................................................... 27
Changing the Fan Settings ................................................................................................................... 27
Changing the Filter Settings ................................................................................................................. 28
Advanced Thermostat Operations ..................................................................29
Overview .......................................................................................................................... 29
Changing User Preferences ............................................................................................ 29
Security Code Screen ........................................................................................................................... 29
Accessing Advanced Setup Options ..................................................................................................... 29
Entering the Security Code................................................................................................................... 30
Change Security Code Screen .............................................................................................................. 30
Changing the Security Code ................................................................................................................. 30
User Preferences Screen ...................................................................................................................... 31
Changing the Temperature Scale......................................................................................................... 32
Changing the Date and Time Format.................................................................................................... 32
Changing the Backlight Settings .......................................................................................................... 33
Disabling the Filter Change Reminder.................................................................................................. 33
Disabling the Weather Alert Icon ......................................................................................................... 34
Disabling the Forecast Screens ............................................................................................................ 34
Disabling the Screen Saver................................................................................................................... 34
Button Lockout Screen ......................................................................................................................... 35
Locking the Buttons.............................................................................................................................. 35
Locking the Temperature Settings ....................................................................................................... 36
Locking the Fan Settings ...................................................................................................................... 36
Locking the Mode Settings ................................................................................................................... 37
Advanced Setup Screen........................................................................................................................ 37
Changing the Type of HVAC System..................................................................................................... 38
Changing the Type of Fossil Fuel.......................................................................................................... 39
Activating the External Sensor ............................................................................................................. 39
Activating the Internal On-board Sensor ............................................................................................. 39
Activating the On-board Humidity Sensor............................................................................................ 40
Setting the Date and Time on the Thermostat ..................................................................................... 40

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Turning on Diagnostic Mode................................................................................................................. 41
Turning on the Humidification and Dehumidification Systems............................................................ 41
Turning on Comfort Recovery .............................................................................................................. 42
AxLink Communications Screen ........................................................................................................... 42
Switching AxLink Devices ..................................................................................................................... 42
Thermostat Setup........................................................................................................... 43
Thermostat Setup Screen..................................................................................................................... 43
Setting First and Second Stage Differentials........................................................................................ 44
Setting the Deadband Temperature Difference ................................................................................... 45
Setting the Temperature Offset............................................................................................................ 45
Setting the Balance Point for a Heat Pump System.............................................................................. 45
Programming ..................................................................................................47
Overview ......................................................................................................................... 47
SEND_COMMANDs .......................................................................................................... 47
CLOCK .................................................................................................................................................................................... 47
MESSAGE ............................................................................................................................................................................... 47
RESET..................................................................................................................................................................................... 47
SLEEP ..................................................................................................................................................................................... 47
VER......................................................................................................................................................................................... 47
WAKE ..................................................................................................................................................................................... 47
ZAP!........................................................................................................................................................................................ 47
Color ViewStat Thermostat Commands ......................................................................... 48
5-Day Forecast Commands................................................................................................................... 48
FH........................................................................................................................................................................................... 48
FL ........................................................................................................................................................................................... 48
FK ........................................................................................................................................................................................... 48
AxLink Commands ................................................................................................................................ 49
BK........................................................................................................................................................................................... 49
CD .......................................................................................................................................................................................... 49
CF........................................................................................................................................................................................... 49
?EXTERNAL_TEMP.................................................................................................................................................................. 49
FILTER.................................................................................................................................................................................... 49
?FILTER.................................................................................................................................................................................. 49
FM .......................................................................................................................................................................................... 50
LK ........................................................................................................................................................................................... 50
MD.......................................................................................................................................................................................... 51
PG .......................................................................................................................................................................................... 51
PRESSURE.............................................................................................................................................................................. 51
?SERIAL ................................................................................................................................................................................. 51
AxLink Channels .............................................................................................................. 52
SP............................................................................................................................................................................................ 52
ST............................................................................................................................................................................................ 52
AxLink Levels .................................................................................................................. 54
Weather Duet Module..................................................................................................... 54
i!-Weather Setup Pages ........................................................................................................................ 55
Changing the Date and Time ................................................................................................................ 56
Changing the Humidity Settings........................................................................................................... 57
Changing the Humidity Mode ............................................................................................................... 57
Changing the Heat and Cool Settings................................................................................................... 58
Changing the Fan Mode ........................................................................................................................ 58

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Changing the HVAC Mode..................................................................................................................... 59
Changing the Hold Mode ...................................................................................................................... 59
Entering Location by Zip Code.............................................................................................................. 60
Entering Location by Station ID............................................................................................................ 60
Changing Temperature Units ............................................................................................................... 60
Changing Wind Speed Units ................................................................................................................. 60
Changing Pressure Units ...................................................................................................................... 60
Auto Refresh Interval Select................................................................................................................. 60

ENV-VST-C ViewStat Color Communicating Thermostat
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ENV-VST-C ViewStat Color Communicating Thermostat
Overview
The ENV-VST-C ViewStat Color Communicating Thermostat (FG2050-12) enables you to completely control your heating,
ventilation, and air-conditioning (HVAC) system. The thermostat provides the current temperature (from an on-board sensor, a
remote sensor, or an average of the on-board and remote sensors), controls and displays humidity, and displays the current
outdoor temperature. The ViewStat Color Thermostat displays this information on a 3.5" (8.89 cm) color display. In addition, the
ViewStat Color Thermostat provides the current day's weather forecast along with a five-day forecast. The forecast information is
driven from AMX’s i!-Weather application.
The thermostat receives the forecast information from a NetLinx Master, with an internet-enabled IP connection, via AxLink. A
three-year subscription to i!-Weather is included with purchase of the thermostat.
System Components
The following table lists the specifications for the ViewStat Color Communicating Thermostat:
FIG. 1 Front panel components
ENV-VST-C Specif ications
Control Voltage 24 VAC (interfaces with a power supply through the R-C terminals)
Warning: Exceeding the control voltage may cause damage to the thermostat.
Switched Voltage 18 – 30 VAC, 57-63 Hz
Maximum Operating Current • 2 amps total at rated voltage, through all outputs.
• 1 amps through any one output.
Minimum System Power 24VAC, 48VA
Maximum Surge Current 2.0 A
Internal Battery CR2032 for maintaining real-time clock settings during a power loss.
Control Accuracy ±1.0° F (± 0.56° C)
±3% relative humidity
Operating Range • Temperature: 40°-99° F (5°-37° C)
• Humidity: 5%-95% RH non-condensing
Certifications • IC
•FCCClassB
•CE
• IEC60950
Mode/Select button
Navigation buttons
Display

ENV-VST-C ViewStat Color Communicating Thermostat
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The following table lists the specifications for the ENV-VST-TSO Outdoor Temperature Sensor:
ENV-VST-C Specif ications (Cont.)
Front Panel Components:
Main LCD display 3.5" (8.89 cm) color QVGA (320 x 240) Thin Film Transistor Liquid Crystal Display (TFT-LCD). The main
display provides the mode status, temperature, and system status information.
Navigation buttons The Navigation buttons are used to change various parameters on the thermostat, including the
temperature setpoints. These buttons are located beneath the display.
Mode/Select button The Mode/Select button is used to navigate through the various thermostat screens, including the weather
screens. This button is located beneath the display.
Circuit Board Components:
Communication and HVAC
Equipment connectors
Terminals with captive-wire connectors that connects to the thermostat, HVAC equipment, control system,
remote sensors, and power supply. See the Communication and Equipment Terminal Wiring
Definitions section on page 11 for more information.
Enclosure:
Material White plastic and removable front panel. The panel can be painted to match wall decor.
Warning: If you paint the panel, do not paint over the exposed thermistor. Doing so can cause the external
temperature sensor to work improperly.
Dimensions (HWD) 5.31" x 3.93" x 1.18" (13.48 cm x 9.98 cm x 2.99 cm)
Weight 5.29 oz. (150 grams)
Included Accessories ENV-VST-C ViewStat Color Communicating Thermostat Installation Guide (93-2050-01)
ENV-VST-TSO ViewStat Indoor/Outdoor Temperature sensor (FG2050-22)
Duet i!-Weather application (FG070-518), three-year subscription
Optional Accessories ENV-VST-TSF ViewStat Indoor Flush Mount Temperature Sensor (FG2050-21)
ENV-VST-TSO Outdoor Temperature Sensor Specifications
Sensing Element: Thermistor (thermal resistor)
Accuracy: ±0.6° C from -20° to 60° C (-4° F to 140° F)
Operating Temperature Range: -50° C to 110° C (-58° F to 230° F)
Temperature Response: NTC Thermistor
Connection: 1" (2 1/2 cm) 24 AWG pigtails
Mounting: Surface mount or 1/4" hole
Color: White plastic case
Threaded Case Length: 1 3/16 in. (30 mm)
Threaded Case Diameter: 1/4 in. (7 mm)
Sensor Face Diameter: 1/4 in. (7 mm)
Sensor Face Thickness: 1/13 in. (2 mm)
Weight: 0.88 oz. (29.94 g)

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ENV-VST-C - Instruction Manual
Installation and Wiring
Overview
This section covers the installation and wiring of a ViewStat Color Communicating Thermostat system.
DANGER: 120 volts may cause serious injury from electrical shock. Disconnect electrical power to the HVAC system before
starting installation. This system is a low-voltage system. Improper installation may cause serious injury from electrical shock.
This system must be installed by a qualified contractor in accordance with NEC Standards and applicable local and state codes.
CAUTION:
If you are using more than one thermostat on a single power transformer, use the maximum total current draw of all of
the thermostats on the transformer times the voltage for the total "VA draw" of the thermostats on that individual transformer; then
keep that value under 50% of the VA rating of the transformer.
Disconnecting Power to All HVAC Equipment
Since the thermostats wire directly to the HVAC equipment, you must shut off the power at the equipment. You can generally
accomplish this by turning off the disconnect switch located near the equipment. If an obvious disconnect switch is unavailable, you
need to remove the circuit breaker or shut down the fuse serving the equipment.
CAUTION: Failure to disconnect power could result in damage to the HVAC equipment or thermostats. Leave the power disconnected
until you have made all other electrical connections and checked them for accuracy.
Selecting the Thermostat Location
Determine if the thermostat will be operating alone, or with remote temperature sensors. If the unit is stand-alone there are certain
measures that must be taken to ensure accurate temperature control.
Stand-Alone Thermostat Mounting Criteria
Mount on an interior wall.
In a room frequently occupied.
At least 18 inches (45.72 cm) from any outside wall.
Approximately 5 feet (1.52 m) above the floor. Check with local building codes for height requirements in commercial
applications.
DO NOT locate the thermostat:
Behind doors, in corners or other dead air spaces.
In direct sunlight or near lamps, appliances or other sources of radiant heat.
On an outside wall or wall exposed to an unconditioned space (i.e. garage, etc.).
In the flow path of a supply register, in stairways or near outside doors.
On a wall where concealed pipes and/or duct work will affect the thermostat.
Near sources of electrical interference such as arcing relay contacts.
Remote Temperature Sensors
When choosing an installation location for the remote sensor, follow the guidelines for placement of the thermostat, and locate the
sensor where its operating range (see the ENV-VST-C Specifications table on page 7) will not be violated (i.e. do not install in a
cold garage or hot equipment room).
See the Installing a Remote Sensor section on page 16 for details.
Removing the Faceplate from the Base
No tools are required to disassemble the thermostat - simply use your hands to pull the front panel off of the base.
CAUTION: Loss of internal programs may result from static discharge to the thermostat circuit board. Touch a grounded metal object
to discharge any static charge before handling the circuit board.
Mounting the Base to a Wall
You should only mount the ViewStat Color Communicating Thermostat onto a sheetrock wall with the anchors and screws provided
with the unit. There are four screw holes located on the base of the thermostat.
1. Place the base over the wire hole opening in the wall. Level the base (leveling required for appearance only) and mark the
screw hole mounting locations.
2. Using the supplied wall anchors, drill 1/4" hole in the center of the marked locations, and tap the wall anchors into the holes.
If using the supplied screws only, drill a 3/32" hole in the center of the marked locations.
NOTE: Minimize the wire entry hole size and seal. Drafts from inside the wall could affect temperature readings.
3. Fasten the base to the wall with the supplied screws.
4. Seal the wire entry with caulk, drywall putty, or insulation.

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ENV-VST-C - Instruction Manual
Wiring the Thermostat
NOTE: A qualif ied HVAC technician should perform these steps to ensure proper termination.
1. Make sure the HVAC system power is off.
2. Strip 1/4" (0.63 cm) of insulation from each wire you are using.
3. Secure the wires into the terminals on the base according to the appropriate wiring diagram, as described below. Refer to the
Wiring Diagrams on page 12.
NOTE: Use color-coding practices (i.e. white wire to W terminal) whenever possible.
Single Stage Furnace and Single Stage A/C - Refer to the Single Stage Furnace and Single Stage A/C on page 12.
Dual Stage Furnace and Dual Stage A/C - Refer to the Dual Stage Furnace and Dual Stage A/C on page 12.
Roof Top Unit with Dual Stage Heat and Dual Stage Cool - Refer to the Roof Top Unit with Dual Stage Heat and Dual Stage
Cool on page 13.
Boiler with A/C with Separate Transformers - Refer to the Boiler and A/C with Separate Transformers on page 13.
Single Stage Heat Pump - Refer to the Single Stage Heat Pump on page 14.
Two Stage Heat Pump - Refer to the Two Stage Heat Pump on page 15.
First Stage Radiant Floor Heat, Second Stage Furnace One Stage of Cooling - Refer to the First Stage Radiant Floor Heat,
Second Stage Furnace with Single Stage Cooling on page 16.
4. Check each wire to ensure it is securely fastened, not broken, and any exposed wires are not touching each other.
Wiring Terminals
ViewStat Color Communicating Thermostats are equipped with terminals RC, RH, C, Y, W, G, O, B, S1, S2, L1, L2, L3, and L4. You can
use terminals S1 and S2 to accommodate a remote temperature sensor (see the Installing a Remote Sensor section on page 16 for
more information).
Terminals L1-L4 connect to the AxLink cable. The remaining terminals are used to control various types of heating and cooling
systems detailed in the following sections. FIG. 2 displays the layout of the terminals on the thermostat’s motherboard.
CAUTION: Applying voltage to the external temperature sensor pins (S1 and S2) can cause permanent damage to the thermostat.
FIG. 2 Te rm inal la yo u t

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Communication and Equipment Terminal Wiring Definitions
The following table lists the communication and equipment terminal wiring definitions for the thermostat.
NOTE: On older model Color ViewStat thermostats, the 2nd stage heat on Two Stage Heat Pump systems wires to the W2 terminal. On
newer thermostat models, 2nd stage heat wires to the Y2 terminal. If you replace an older model thermostat with a newer model, you
must rewire the terminals for two stage heat pumps. Failure to do so could result in 2nd stage heating not working properly.
Preparing Captive Wires
Follow these steps to connect the wiring into a captive-wire connector:
1. Strip 1/4 inch off the wire insulation for all four wires.
2. Tin 2/3 of the exposed wire.
3. Insert each wire into the appropriate captive-wire connector up to the insulation.
4. Tighten the captive screws to secure the fit in the connector.
Wiring Guidelines
The ViewStat Color Communicating Thermostat accepts configuration and weather information from a NetLink Integrated master
via an AxLink bus. Use 18 AWG wire to connect terminals L1-L4 on the ViewStat to the AxLink device.
See the Communication and Equipment Terminal Wiring Definitions section on page 11 for more information on the terminals on
the ViewStat.
NOTE: The ViewStat Color Communicating Thermostat interfaces with a 24 VAC power supply from the heating/cooling unit through
its RC terminal. You should not connect the power wiring from the AxLink device to the thermostat with the intent of using the AxLink
device to provide power to the thermostat. The L1 terminal on the thermostat can accept the AxLink +12VDC wire and you can
connect the wire to the terminal if you want to assure there are no loose wires inside the thermostat, but you should not power the
thermostat by running a jumper to the RC pin.
Wiring for AxLink
Connect the AxLink wiring from the thermostat to the connector on the AxLink device as shown in FIG. 3.
You can connect the AxLink device to a NetLinx Master by following the instructions in the AxLink device’s instruction manual.
Communication and Equipment Terminal Wiring Definitions
RH 24 VAC in
RC 24 VAC in for AC relays. If a separate 24 VAC is not supplied to the RC terminal, install a jumper from RH to RC.
C24VACcommon
G1 Fan on 1. If you are using a single speed fan, you should connect it to the G1 terminal, since the fan speed is set to Low by default.
On a multi-speed fan, G1 is the lowest speed.
G2 Fan on 2. On a multi-speed fan, G2 is the medium speed.
G3 Fan on 3. On a multi-speed fan, G3 is the highest speed.
W1 1st stage heat or emergency heat for a heat pump system.
W2 2nd stage heat
Y1 1st stage compressor
Y2 2nd stage compressor.
B Reversing valve (heat). Either the B or O relay will be connected to the reversing valve based on the type of reversing valve used.
Connect one or the other. DO NOT CONNECT BOTH.
O Reversing valve (cool). Either the B or O relay will be connected to the reversing valve based on the type of reversing valve used.
Connect one or the other. DO NOT CONNECT BOTH.
DEH Dehumidify
HUM Humidify
S1 External thermistor. The Color ViewStat supports only one external sensor.
S2 External thermistor. The Color ViewStat supports only one external sensor.
L1 AxLink PWR. This terminal is optional for AxLink connections.
L2 AxLink AxP. This terminal is required for AxLink connections.
L3 AxLink AxM. This terminal is required for AxLink connections.
L4 AxLink GND. This terminal is required for AxLink connections.
FIG. 3 AxLink wiring

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Wiring Diagrams
The following sections display wiring diagrams for the types of HVAC systems that are compatible with the thermostat:
Single Stage Furnace and Single Stage A/C
The thermostat automatically defaults to One Stage Furnace for the HVAC System setting when you install it. For information about
changing the HVAC System setting, see the Changing the Type of HVAC System section on page 38.
Dual Stage Furnace and Dual Stage A/C
See the Changing the Type of HVAC System section on page 38 for information on indicating the thermostat is connected to a Dual
Stage Furnace and Dual Stage A/C system.
FIG. 4 Single Stage Furnace and Single Stage A/C wiring
FIG. 5 Dual Stage Furnace and Dual Stage A/C wiring

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ENV-VST-C - Instruction Manual
Roof Top Unit with Dual Stage Heat and Dual Stage Cool
See the Changing the Type of HVAC System section on page 38 for information on indicating the thermostat is connected to a Roof
Top Unit with Dual Stage Heat and Dual Stage Cool system.
Boiler and A/C with Separate Transformers
See the Changing the Type of HVAC System section on page 38 for information on indicating the thermostat is connected to a Boiler
and A/C with Separate Transformers system.
FIG. 6 Roof Top Unit with Dual Stage Heat and Dual Stage Cool wiring
FIG. 7 Boiler and A/C with Separate Transformers wiring

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ENV-VST-C - Instruction Manual
Single Stage Heat Pump
NOTE: Either the B or O relay will be connected to the reversing valve based on the type of reversing valve used (B is energized for
heating, O is energized for cooling). Connect one or the other. DO NOT CONNECT BOTH.
See the Changing the Type of HVAC System section on page 38 for information on indicating the thermostat is connected to a Single
Stage Heat Pump system.
FIG. 8 Single Stage Heat Pump wiring
See note below

Installation and Wiring
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ENV-VST-C - Instruction Manual
Two Stage Heat Pump
NOTE: Either the B or O relay will be connected to the reversing valve based on the type of reversing valve used (B is energized for
heating, O is energized for cooling). Connect one or the other. DO NOT CONNECT BOTH.
See the Changing the Type of HVAC System section on page 38 for information on indicating the thermostat is connected to a Two
Stage Heat Pump system.
FIG. 9 Tw o S t a g e H e a t P u m p w i r i n g
See note below

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First Stage Radiant Floor Heat, Second Stage Furnace with Single Stage Cooling
See the Changing the Type of HVAC System section on page 38 for information on indicating the thermostat is connected to a First
Stage Radiant Floor Heat, Second Stage Furnace with Single Stage Cooling system.
Installing a Remote Sensor
The ViewStat Color Communicating Thermostat has an onboard temperature sensor that can read and report the temperature at
the location of the unit (see FIG. 11). The onboard temperature sensor detects the current room temperature every 30 seconds.
NOTE: Do not paint or tape over the onboard temperature sensor. Doing so can cause the sensor to work improperly.
NOTE: The onboard temperature sensor reports any detected temperature between 40° – 99° F (5° – 37° C). Temperatures outside
this range will not display on the thermostat screen. In this case, the temperature reading appears blank.
You can install an additional remote sensor to get a temperature reading from a location away from the thermostat. If you install a
remote sensor, you can use the temperature reading as the main reported temperature, or you can use the temperature reading
with the reading from the onboard sensor to report an average temperature for the zone.
The ViewStat Color Communicating Thermostat supports only one installed remote sensor. The sensor connects to the S1 or S2
terminal on the ViewStat. See the Communication and Equipment Terminal Wiring Definitions section on page 11 for more
information on the terminals on the thermostat.
FIG. 10 First Stage Radiant Floor Heat, Second Stage Furnace with Single Stage Cooling wiring
FIG. 11 Onboard temperature sensor
Onboard
temperature
sensor

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ENV-VST-C - Instruction Manual
You can install the indoor/outdoor temperature sensor that ships with the unit, or you can install an indoor flush mount sensor
(FG2050-21), available for purchase separately. You can use either sensor with the thermostat, but not both at the same time, as
the thermostat supports only one external sensor. Refer to the ViewStat Color Communicating Thermostat User Guide for
information on enabling or disabling each sensor.
Installing the Outdoor Temperature Sensor
FIG. 12 displays the ENV-VST-TSO Outdoor Temperature sensor (FG2050-22). You can install this sensor outdoors for a reading of
the outdoor temperature that the sensor reports back to the thermostat. You can also install this sensor indoors for an extra indoor
temperature reading. You can use the indoor reading with the reading from the on-board temperature sensor on the thermostat to
report an average indoor temperature.
The sensor has a 1" head that protrudes from the wall and a connected wire that plugs into a port on the thermostat. You can use
a maximum of 300 ft (91.44 m) of wire for connecting the indoor/outdoor remote sensor to the thermostat.
Follow these steps to install the indoor/outdoor remote sensor:
1. Drill a 1/4" hole into the surface where you want to install the sensor.
2. Fish the cable that connects to the sensor through the 1/4" hole in the wall until the edge of the sensor, where the cord meets
the sensor, is flush against the wall.
3. Apply caulk, drywall putty, insulation, or any other appropriate sealant to the hole in the wall around the sensor to seal the
hole.
4. Attach the connecting wires from the sensor to the S1 and S2 terminals on the thermostat (see FIG. 13). It does not matter
which wire you connect to either terminal.
NOTE: Applying voltage to the external temperature sensor pins (S1 and S2) can cause permanent damage to the thermostat.
Installing the Indoor Flush Mount Sensor
FIG. 14 displays the two pieces of the Indoor Flush Mount Temperature sensor (FG2050-21). The two pieces are the sensor body
with the connected wire and the threaded outer case of the sensor.
FIG. 12 Outdoor Temperature Sensor
FIG. 13 Indoor/outdoor sensor wiring to S1 and S2 terminals
FIG. 14 Indoor Flush Mount Sensor
Connecting wires
Sensor head
Sensor wires

Installation and Wiring
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ENV-VST-C - Instruction Manual
The following table lists the specifications for the Indoor Flush Mount Temperature sensor:
You can use a maximum of 300 ft (91.44 m) of wire for connecting the Indoor Flush Mount Temperature sensor to the thermostat.
Follow these steps to install the indoor flush mount sensor:
1. Drill a ½" hole into the drywall where you want to install the sensor.
2. Fish the cable that connects to the sensor from behind the drywall and out through the ½" hole so that 6" - 12" of the cable
hangs through the hole.
3. Feed the sensor wire through the center of the threaded outer case of the sensor and connect it to the cable that is hanging
through the hole in the wall as shown in FIG. 15.
4. Carefully feed the wires and wire-nuts through the ½" hole and into the wall. Use your hands to lightly screw the threaded
outer case into the hole in the wall as shown in FIG. 16.
5. Use a screwdriver to screw the threaded outer case of the sensor the rest of the way into the ½" hole in the drywall. Be careful
to not pinch the wire while you are screwing in the case. Screw the case into the wall until the front surface of the case is
inserted just past the surface of the drywall.
6. Use your thumb to carefully push the sensor body into the threaded outer case until the face of the sensor body is flat against
the drywall.
7. Attach the connecting wires from the sensor to the S1 and S2 terminals on the thermostat (see FIG. 13). It does not matter
which wire you connect to either terminal.
Indoor Flush Mount Temperature Sensor Specifications
Threaded Case Length: 1 in. (25.4 mm)
Threaded Case Diameter: 0.69 in. (17.5 mm)
Sensor Face Diameter: 0.75 in. (19 mm)
Sensor Face Thickness: 0.21 in. (5.4 mm)
Weight: 0.15 oz. (0.0042 kg)
FIG. 15 Sensor wire connected to cable
FIG. 16 Outer case screwed into wall

Setup and Configuration
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ENV-VST-C - Instruction Manual
Setup and Conf iguration
Overview
The ViewStat Color Communicating Thermostat provides the current temperature, controls and displays humidity, and displays the
current outdoor temperature. The ViewStat Color Communicating Thermostat displays this information on a 3.5" (8.89 cm) color
display. In addition, the ViewStat Color Communicating Thermostat provides the current day's weather forecast along with a
five-day forecast, driven from AMX’s i!-Weather application.
This chapter provides information about the different screens on the ViewStat Color Communicating Thermostat, how to navigate
through them, and how to establish settings on each screen.
Front Panel Components
This section describes the front panel components and gives instructions for operating the ViewStat Color Communicating
Thermostat (see FIG. 1 on page 7).
Display
The ViewStat Color Communicating Thermostat provides the current temperature condition including indoor and outdoor
temperature, the current weather conditions, and the Five Day Forecast. The thermostat displays this information on a 3.5" (8.89
cm) color QVGA (320 x 240) Thin Film Transistor Liquid Crystal Display (TFT-LCD).
Navigation Buttons
The ViewStat Color Communicating Thermostat is equipped with three tactile buttons that support the thermostat’s main functions
and its backlight options. When you press any button, the display backlight lights up for 30 seconds. The Navigation buttons are
used to change various parameters on the thermostat, including the temperature setpoints. While on the Main screen (FIG. 17),
pressing the navigation buttons puts the thermostat in cool/heat setpoint adjust mode. These buttons are located beneath the
faceplate.
Mode/Select Button
The Mode/Select button is used to navigate through the various thermostat screens, including the weather screens. This button is
located beneath the faceplate. Pressing Mode/Select for the first time takes the display from an Inactive state to an Active state.
Pressing Mode/Select again takes you to the Current Weather screen (provided you have not disabled this screen.) Pressing and
holding Mode/Select for three seconds opens the Hold Mode menu (see the Changing Hold Mode section on page 20 for more
information.)
Navigating the ViewStat Color Communicating Thermostat
This section describes the various screens on the thermostat, and the options on each screen.
Main Screen
The Main screen (FIG. 17) of the ViewStat Color Communicating Thermostat displays the current date, time, and indoor
temperature. You can also view the current heating and cooling setpoints and the humidity.
The current day’s forecasted high and low temperatures and weather condition appear on the bottom of the screen. The ViewStat
Color Communicating Thermostat receives this information from AMX’s i!-Weather service.
FIG. 17 Main screen
Current room
temperature
Current
forecast
Cool setpoint
Heat setpoint
Status icons

Setup and Configuration
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ENV-VST-C - Instruction Manual
The following table describes the status icons that may appear on your thermostat:
While many of the items on the Main screen are view-only, you change the cool and heat setpoints, the H/C mode, and fan mode on
this screen. The following sections describe how to change items on the Main screen.
Changing the Heating and Cooling Setpoints
You can change the heating and cooling setpoints on the Main screen. Changing the setpoints places the thermostat in temporary
hold mode and uses the new temperature settings. The setpoints change back to the program mode setpoints at the next program
time. You cannot change the heating and cooling setpoints if the thermostat is in permanent hold mode. See the Changing Hold
Mode section on page 20 for more information about Hold modes.
1. On the Main screen, press either of the navigation buttons to access the heating or cooling setpoints that appear on the left
side of the screen. When either of the setpoints blinks, you can change the setpoint by using the navigational buttons to
increase or decrease its value.
2. Press Mode/Select to select the next setpoint, and use the navigational buttons to increase or decrease its value.
The setpoints continue to blink and are able to be changed until the thermostat reaches a 10-second timeout. Press and hold
Mode/Select for three seconds for changes to immediately take effect.
NOTE: Depending on the H/C mode you select, you may only see one setpoint on the Main screen. (If you turn off the HVAC system,
neither appears.) See the Changing the Heating/Cooling Mode section on page 21 for more information.
Changing Hold Mode
You can access Hold Mode by pressing and holding Mode/Select for three seconds. You can use the navigational buttons to scroll
through the list. You can also change the Hold mode on the Thermostat Mode screen.
The change takes effect when you press Mode/Select or after a 10-second timeout.
Main Screen Status Icons
Icon Description
Dehumidify - This icon appears whenever active dehumidification is occurring.
Humidify - This icon appears whenever active humidification is occurring.
Fan - This icon appears whenever the fan is running.
Auxiliary Heat - This icon appears whenever auxiliary heat is running on Heat Pump systems.
Cooling - This icon has a light-grey state which displays when the HVAC system is not actively cooling. This icon changes to a
color representation when the system is actively cooling.
Heating - This icon has a light-grey state which displays when the HVAC system is not actively heating. This icon changes to a
color representation when the system is actively heating.
FIG. 18 Hold Mode menu
Hold Mode Options
Permanent Sets the thermostat into Permanent Hold mode. When in Permanent Hold mode, the thermostat disregards the heating and
cooling settings established on the Program screen until the user sets the Hold mode back to Program.
Temporary Sets the thermostat into Temporary Hold mode. When in Temporary Hold mode, the thermostat disregards the heating and
cooling settings established on the Program screen until the start of the next program cycle.
Program Sets the thermostat to use the settings established in the program settings. See the Establishing Daytime/Nighttime
Temperature Settings section on page 25 for more information.