Honeywell W8835 User Manual

68-0258ES-04

W8835 EnviraZone Panel

FEATURES

• Controls up to three stages heat and two stages cooling of single-stage, multi-stage, conventional, or heat pump.

• Controls up to three zones and can be expanded up to nine zones with two W8703A DIM.

• Uses VisionPRO® IAQ or FocusPRO communicating thermostats for manual or automatic changeover by zone.

• Supports dehumidification, humidification and ventilator controls.

• Purge timer protects equipment between calls for heat or cool with choice of panel or HVAC equipmentcontrolled fan.

• System and zone damper LEDs indicate system and damper status.

• Individual zone fan control.

• Supports C7835 Discharge Air Temperature Sensor for

APPLICATION

The W8835 EnviraZone Panel controls single-stage, multistage, conventional or heat pump heat/cool equipment. It controls three zones, and is expandable up to nine zones with two additional W8703A Damper Interface Modules (DIM). For Internet access: http://yourhome.honeywell.com

capacity control with adjustable high and low limits and equipment failure indication.

• Controls duel fuel equipment when used with an external fossil fuel kit.

PRODUCT DATA

For technical support, call: 1-800-828-8367.

IMPORTANT

Please read these instructions and keep them in your records.

Contents

Application.........................................................................1

Features ............................................................................2

Specifications ....................................................................2

Ordering Information .........................................................2

Installation .........................................................................4

Startup and Checkout ........................................................8

Operation...........................................................................8

Troubleshooting.................................................................11

W8835 ENVIRAZONE PANEL

SPECIFICATIONS

Input Ratings:

Voltage: 20-30 Vac, 50/60 Hz. Power: 11 VA nominal, Class II.

Output Ratings (dampers and HVAC equipment):

1.5A run, 200,000 cycles (30 Vac) 3.5A inrush.

1.5A run, 100,000 cycles (30 Vac) 7.5A inrush.

Humidity Ratings:

90 percent RH at 95°F, non-condensing.

Temperature Ratings:

Shipping: -20 to 120°F. Operating: -40 to 150°F.

LED:

SYSTEM mode LEDs (5) used to communicate equipment

status: Red Heat: Heat mode. Green Cool: Cool mode. Yellow Purge: Purge mode. Green Fan: Fan mode. Red Em Heat: Emergency Heat mode.

ZONE LEDs (3) used to communicate damper status:

Green: Dampers are open or opening. No Color: Dampers are closed or closing.

COM LED (1) used to indicate communication status:

Flashing Green: Panel is transmitting or has received data. No color: Communications are idle.

Dimensions: 12-3/4 in. W x 10-3/4 in. H x 1-7/8 in. D.

See Fig. 1.

Finish: W8835: Taupe cover, olive-gray base.

Mounting: Mounts with four screws (provided) through holes

in cabinet back (wall anchors provided).

Wiring: Eighteen-gauge wire for all equipment and system

connections.

Wiring Connections:

EnviraCom: Four terminal strips (each with three terminals

labeled 1, 2, 3).

Dampers: Three terminal strips labeled M6 (Closed),

M4 (Open), M1 (Common). Transformer 1: R (hot), C (Common). Transformer 2: T1 (hot), T2 (Common). Equipment: Rc, Rh, W1/E, W2, W3/Aux, Y1, Y2, G, O/B. Humidifier: HUM, HUM. Dehumidifier: DHUM, DHUM. Ventilator: VENT, VENT.

Thermostats:

VisionPRO® IAQ TH9421 or FocusPRO THM5320C Thermo-

stats controls single- or multi-stage conventional and heat

pump equipment.

Accessories:

For required accessories, see Table 2. Optional accessories

include the W8735 Telephone Access Module for

telephone dial-in and dial-out capability, and the W8703

Damper Interface Module to control additional zones.

ORDERING INFORMATION

When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the TRADELINE® Catalog or price sheets for complete ordering number.

If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:

1. Your local Honeywell Automation and Control Products Sales Office (check white pages of your phone directory).

2. Honeywell Customer Care

1885 Douglas Drive North

Minneapolis, Minnesota 55422-4386 In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Toronto, Ontario M1V 4Z9. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

68-0258ES—04 2

W8835 ENVIRAZONE PANEL

Dampers:

See Table 1 for suggested dampers. Dampers are connected to

M1 Common, M4 Open, and M6 Closed (see Fig. 5 through 8 for hookups). Connect no more than five ARD or ZD dampers to an individual zone.

Connect no more than five ARD or ZD dampers to the panel

when using one 40 VA transformer; connect no more than ten ARD or ZD dampers when using two 40 VA transformers.

HEAT COOL PURGE FAN EM. HT. COMM ZONE 1 ZONE 2 ZONE 3

10-3/4

(273)

Use SDCR for additional dampers required. If using RRD dampers, refer to RRD installation instructions for maximum number of dampers.

Motor Terminal Damper Action

Common/M1 Common Open/M4 Power Open Closed/M6 Power Close

12-3/4

(324)

1-7/8

(47)

M20594

Fig. 1. W8835 dimensions in in. (mm).

Table 1. Recommended Dampers

Honeywell Damper Type Round Rectangular

For systems > 2000 cfm. MARD or RRD For recommended dampers, call the Honeywell

Zoning Hotline at 1-800-828-8367.

For systems <= 2000 cfm. ARD or RRD ZD

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W8835 ENVIRAZONE PANEL

CAUTION

Table 2. Required Accessories (Not Supplied with Panel).

Accessory Description

40 VA transformers

High and low limit sensor

AT140A1042

C7835A1009

Round static pressure regulator damper SPRD7

SPRD8 SPRD9 SPRD10 SPRD12 SPRD14 SPRD16

Rectangular static pressure regulator damper SPRD12x8

SPRD12x10 SPRD12x12 SPRD20x8 SPRD20x10 SPRD20x12

Supplied in the Y8835 kits.

INSTALLATION

Mounting

Bypass Rating

(cfm)

—

300 400 600 750 1200 1800 2400

1000 1200 1400 1600 2000 3000

RETURN

AIR

Equipment Damage Hazard. Do not mount W8835 inside HVAC equipment.

Mount only on wall or on cold air return.

1. Mount the thermostats in each zone of the living space

using the installation instructions provided with each thermostat.

2. Mount the dampers in the ductwork using the installation

instructions provided with each damper.

3. Mount the W8835 EnviraZone Panel near the HVAC

equipment; locate it on a wall or on the cold-air return. See Fig. 2.

4. Level the W8835 for appearance only.

W8835

IR CLEANER

E LE

CTRONI

C AIR CLEANER

FURNACE

W8835

M31121

Fig. 2. W8835 mounting location.

Wiring

Voltage Hazard. Can cause electrical shock or equipment damage.

Disconnect power before continuing installation.

Wiring must comply with applicable codes, ordinances, and regulations.

68-0258—04 4

W8835 ENVIRAZONE PANEL

12 3

W1 /E

W3/AU X

O/ B

HU M

DE HUM

VE NT

ZONE 1

M6 M4 M1

ZONE 2

M6 M4 M1

ZONE 3

M6 M4 M1

1 2 3 1 2 3 1 2 3 1 2 3

DA MP ER S E NV IR AC OM BUS

DAM PER XF RM

EN VI RACO M XF RM

RE MO VE JU M PER S IF T1 AND T2 ARE USED

HE AT CO OL ZO NE 1 CO M EM HE AT FA N PU RG EZ ON E 3 ZO NE 2

W8835A

DI P SW IT CH SE TT IN GS 1 SEE TA BL EO NO FF 2 SEE TA BL E1 0 3 EN VI RACO M FU RN NO YE S 4 P URG E TI ME 2 MI N3 .5 MI N 5 P URG E FA NH VA C P ANE L 6 P URG E DAM PE RN O CHG OP EN 7 # CO MP ST AG ES 1 2 8 H E AT FA NH VA C P ANE L 9 H P CHANG EO VE RO B 10 UNU SE D

O N

1 2 3 4 5 6 7 8 9 10

#1 # 2 CO NV HT ST G

1 1 1 1 0 2 0 1 3 0 0 HP

24 VOLT/40 VA TR AN SF OR ME R

DO TTE D LI NE S FO R 2ST AG E A PPL IC AT IO NS

SI NG LE TR AN SF OR ME R H EAT I N G/COOLING SYST EM S RE QU IR E A JU M PER TO BE IN ST AL LE D C O NNEC TI NG R H AND RC (FACTORY INSTALLED) .

12 3

EARD- 6

M31122

POWER-CLOSED/ SPRING-OPEN ZD DAMPER

POWER-CLOSED/ SPRING-OPEN ARD DAMPER

C7835A DISCHARGE AIR SENSOR

LED STATES:

Heat LED Heating Mode Cool LED Cooling Mode Purge LED Purge Mode Fan LED Fan Mode Em Heat LED Em Heat Mode COMM LED Communications

ZONE LEDS:

On Damper open or opening Off Damper closed or closing

MOMENTARY PUSH BUTTONS

Boot Clears Microprocessor Purge Override Bypass Purge Mode Discovery Initiates Discovery Mode

Wiring Thermostats

Run wire from the Thermostat 1, 2, 3 terminals to the corresponding terminals on any one of the EnviraCom bus terminal sets. More than one thermostat or other communicating device can be connected to a bus terminal. See Fig. 3.

Wiring Equipment

CONVENTIONAL EQUIPMENT

Connect the first stage heat to W1/E, second stage heat to W2, and third stage heat to W3/Aux. Wire first stage cooling to Y1, and second stage cooling to Y2. See Fig. 3.

If separate HVAC equipment transformers are used for the heating and cooling systems, such as for an oil furnace, wire the heating transformer hot wire to Rh and the cooling transformer hot wire to Rc. Locate the Rh/Rc jumper above the equipment terminals and remove the jumper to expose the two pins.

HEAT PUMP EQUIPMENT

Connect the Y1 terminal to the first stage compressor, and the Y2 terminal to the second stage compressor. W3/Aux is the auxiliary heat and W1/E is the emergency heat. If emergency heat and auxiliary heat use the same piece of equipment, place a jumper from W3/Aux to W1/E and wire it to the resistive heat equipment. See Fig. 4 and 5. See Fig. 6 and 7 for twostage heat pump equipment.

Fig. 3. Conventional equipment wiring diagram.

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W8835 ENVIRAZONE PANEL

For dual fuel equipment using heat pump and fossil fuel, configure the panel as a heat pump and use a fossil fuel kit. Do not use the dual fuel functionality of the VisionPRO® IAQ.

Wiring HVAC Equipment

SINGLE TRANSFORMER HEATING/COOLING SYSTEMS REQUIRE A JUMPER TO BE INSTALLED CONNECTING R

(FACTORY INSTALLED).

HVAC EQUIPMENT

24 VAC

EQUIPMENT

REVERSING VALVE (COOLING/HEATING)

HEATING TRANSFORMER

COOLING TRANSFORMER

Fig. 4. Wiring single-stage heat pump with separate

Auxiliary and Emergency Heat.

SINGLE TRANSFORMER HEATING/COOLING SYSTEMS REQUIRE A JUMPER TO BE INSTALLED CONNECTING R

(FACTORY INSTALLED).

HVAC EQUIPMENT

24 VAC

EQUIPMENT

REVERSING VALVE (COOLING/HEATING)

HEATING TRANSFORMER

COOLING TRANSFORMER

AND R

AUXILIARY HEAT

COMPRESSOR

FAN RELAY

FIELD INSTALLED JUMPER

AND R

AUXILIARY HEAT

COMPRESSOR

FAN RELAY

FIELD INSTALLED JUMPER

L C R

W1/E W

W3/AUX Y

G O/B

M31124

L C R

W1/E W

W3/AUX Y

G O/B

M31124

SINGLE TRANSFORMER HEATING/COOLING SYSTEMS REQUIRE A JUMPER TO BE INSTALLED CONNECTING R

(FACTORY INSTALLED).

AND R

HVAC EQUIPMENT

L C

24 VAC

EQUIPMENT

HEATING TRANSFORMER

COOLING TRANSFORMER

EMERGENCY HEAT RELAY

AUXILIARY HEAT RELAY

FIRST STAGE COMPRESSOR

SECOND STAGE COMPRESSOR

FAN RELAY

REVERSING VALVE (COOLING/HEATING)

W3/AUX Y

G O/B

M31123

Fig. 6. Wiring two-stage heat pump with separate Auxiliary

Heat.

SINGLE TRANSFORMER HEATING/COOLING SYSTEMS REQUIRE A JUMPER TO BE INSTALLED CONNECTING R

(FACTORY INSTALLED).

AND R

HVAC EQUIPMENT

L C

24 VAC

EQUIPMENT

HEATING TRANSFORMER

COOLING TRANSFORMER

AUXILIARY HEAT RELAY

FIRST STAGE COMPRESSOR

SECOND STAGE COMPRESSOR

FAN RELAY

REVERSING VALVE (COOLING/HEATING)

FIELD INSTALLED JUMPER

W3/AUX Y

G O/B

M31125

Fig. 7. Wiring two-stage heat pump with Auxiliary Heat.

Fig. 5. Wiring single-stage heat pump with Auxiliary Heat.

68-0258—04 6

W8835 ENVIRAZONE PANEL

ARD or ZD Dampers

Wire the ARD or ZD Damper to the panel as shown in Fig. 8. Multiple dampers can be wired in parallel. Up to five ARD or ZD dampers can be connected in parallel to one zone. If five to ten dampers are connected to the panel an additional 40VA transformer must be connected to the panel.

Fig. 8. Wiring ARD or ZD damper to panel.

RRD

Wire the RRD dampers to the panel as shown in Fig. 9. Two or more RRD can be wired in tandem as shown in Fig 10. Up to 12 RRD can be wired to one zone. Power the panel with one 40VA transformer if up to 12 dampers are connected to the panel. Power the panel with two 40VA transformers if up to 26 RRD are connected to the panel.

ZONE

1, 2, 3, ETC.

M6 M4 M1

ZONE 1, 2, 3

M6 M4 M1

M 1 M 6

M 4

M1 M6 M4

M31134

Fig. 10. Wiring two RRD dampers in parallel.

MARD Dampers or Dampers using ML6161 Motor Actuator

Wire the MARD Damper or other damper using the ML6161 Actuator to the panel as shown in Fig. 11. These floating control actuators are controlled as two-position devices on the W8835 panel.

The ML6161 motor causes the damper LED to illuminate green constantly. To restore damper position indication, mount end switch 201052B onto the ML6161.

M1 M6 M4

M31133

Fig. 9. Wiring RRD damper to panel.

ZONE PANEL

CONNECTIONS M1 M4

MARD

COM

CCW

M20136A

Fig. 11. Wiring MARD Damper or ML6161 Actuator to

panel.

Transformer

Wire the transformers to the panel (see Fig. 12). One 40 VA, 24 Vac transformer is required to operate the panel and up to five ARD or ZD dampers. The transformer is connected to terminals R and C. The auxiliary transformer is required if up to ten dampers are connected to the panel. It is wired to terminals T1 and T2. If more than five ARD or ZD dampers are required for one zone of if more than ten ARD or ZD dampers are required for the W8835, use the Slave Damper Control Relay (SDCR). Locate the XFRM jumper shown in Fig. 12. These jumpers are shipped in the open, disconnected position. This is the correct position when two transformers are used. When using one transformer to power the panel, place the jumpers in the closed position. Do this by removing the jumpers and installing them so they cover both of their respective pins. If preferred, one 75 VA transformer may be used on this panel instead of two 40 VA. If this is done, leave the jumpers in the open, disconnected position and install a jumper between R and T1. Wire the transformer to R and C.

7 68-0258—04

W8835 ENVIRAZONE PANEL

CAUTION

C T1 T2

24 VAC, 40 VA

TRANSFORMER

(REQUIRED IF

MORE THAN

FIVE DAMPERS)

24 VAC, 40 VA

TRANSFORMER

DAMPER

XFRM

PAN EL

XFRM

M31126

REMOVE XFRM JUMPERS FROM PINS WHEN USING

TWO TRANSFORMERS

Equipment Damage Hazard. Incorrect transformer wiring can damage panel.

Wire transformers in phase when one transformer is wired to R and C and the auxiliary transformer is wired to T1 and T2.

4. On the W8835 Panel, set the DIP switches.

a. Set DIP switches 1, 2, and 7 to assign the

appropriate number of heating and cooling stages. See Tables 5 and 6.

b. Configure other DIP switches, as necessary to fit the

application. See Table 6.

5. On each thermostat, enter the Installer Setup procedures

using the VisionPRO® IAQ Installation Instructions and assign each thermostat a zone number to correspond with its zone damper.

6. Run Discovery by pressing the Discovery button on the

zone control panel.

7. On each thermostat, enter the Installer Setup

procedures using the Installation Instructions and configure other pertinent Installer Setup options. Program the thermostat schedule if the default settings are not desired.

8. Run Discovery by pressing the Discovery button on the

panel.

9. Set Zone one thermostat to heat and raise the setpoint to

call for heat. a. Verify that the heat LED is red.

NOTE: The furnace heat may not come on immedi-

ately. Allow at least 5 minutes for heat to begin after the thermostat calls for heat.

Wiring C7835 Discharge Air Temperature Sensor

Connect wire terminals 1, 2, and 3 to the corresponding terminals on either the W8835 EnviraZone panel or any other EnviraCom device such as a thermostat. Refer to C7835 Installation Instructions for configuration. Multiple devices can be wired in parallel to the each of the 1, 2, 3 terminals.

STARTUP AND CHECKOUT

1. Verify that the equipment, thermostats, transformer, and

Discharge Temperature Sensor are wired correctly. If one transformer is powering the panel, install the XFRM jumper. If two transformers are powering the panel, leave the XFRM jumper in the open position.

2. Power up the W8835. Verify that all LEDs except COM

illuminate for five seconds.The board should then enter the Purge mode with all dampers open. The damper LEDs are green to indicate the dampers are open. The COM LED begins to blink.

3. Press the Purge Override button to terminate the Purge

mode.

68-0258—04 8

Fig. 12. Wiring transformer(s) to panel.

b. Verify that Zone one LED remains green. c. Verify that all other zone LEDs are not illuminated. d. Change thermostat mode from Heat to Off.

10. Set Zone two thermostat to heat and raise the setpoint to

call for heat. a. Verify that the heat LED is red. b. Verify that Zone two LED remains green. c. Verify that all other zone LEDs are not illuminated. d. Change thermostat mode from Heat to Off.

11. Alternatively, set a thermostat to Cool, lower the

setpoint to call for cooling, wait five minutes, and verify correct operation.

OPERATION

Sequence of Operation

When there is no call for heat, cool or fan, the board is in the idle mode, indicated with no system LEDs illuminated, see Table 3. Damper LEDs are green to indicate open. On a call for heat, cool, or fan, the calling zone damper stays open and the damper LED remains illuminated; the other zone dampers close and corresponding damper LEDs do not illuminate.

The W8835 panel energizes the HVAC equipment and conditioned air is delivered to the calling zone. The heat LED (red), cool LED (green), or fan LED (green) illuminates to indicate equipment operation.

The fan LED illuminates only on a call for fan; it does not illuminate during a call for heat or cool. When the heat/cool call is satisfied, the system enters the Purge mode, indicated by the Purge LED (yellow). Damper positions either remain in the same positions as at the end of the call for heat or cool (default) or open, depending on the position of DIP switch 6. After purge, all dampers return to the Open position.

COM LED Operation

The green COM LED flickers as the W8835 communicates with the other EnviraCom devices:

LED blinks rapidly—indicates device is currently

transmitting information on the communications bus.

W8835 ENVIRAZONE PANEL

LED blinks once—indicates device received and

acknowledged a message. LED on constantly— indicates panel failure. Replace panel. LED off constantly—indicates a wiring problem.

Table 3. LED Indicators

LED Color Illuminated Not Illuminated

Heat Red Heat call. No heat calls. Cool Green Cool call. No cool calls. Purge Amber Purge mode. Not in Purge mode. Fan Green Fan only call. No fan only call. Em Heat Red Emergency Heat mode. Not in Emergency Heat mode. Zone 1, 2, 3 Green Damper is open or opening. Damper is closed or closing.

An LED change precedes the corresponding relay change by as much as six seconds.

Purge Mode

At the end of every call for heat or cool, the panel enters a Purge mode. DIP 4 configures the panel to purge for two (default) or three and one-half minutes. DIP switch 5 configures the panel or the HVAC equipment to operate the fan during purge.

The Purge LED lights to signal that the system is in the Purge mode. Pressing the purge override button overrides the Purge mode.

Individual Zone Fan Control

When all zones are satisfied, the fan switch of each thermostat controls the fan operation for that zone. When the fan setting is “ On”, the fan is energized, the fan LED illuminates and the dampers close to zones where the fan setting is “Auto”. If there is a call for heat or cool during this time, the fan mode ceases, and the heat or cool call is honored. When the zone calling is satisfied, and Purge mode has ended, the fan call resumes.

Single and Multi-Stage Conventional

Unless there is a new call for heat or cool during the Purge mode, all dampers are moved to the Open position at the end of purge. DIP switch 6 is used if it desired to open all dampers during the Purge mode.

Table 4. Purge Configuration

DIP Switch

Number

4 Off (Down) 3.5 minutes purge 4 On (Up) 2 minutes purge

Table 5. Fan Control Configuration

DIP Switch

Number

5 Off (Down) Panel control of fan

5 On (Up) HVAC control of fan

Status Purge

Status Fan Control

in Purge

Heat Operation

The panel can control up to three stages of heating and two stages of cooling based on thermostat demand. Set DIP switches 1 and 2 for 1, 2 or 3 stages of heat. Set DIP switch 7 for one or two stages of cooling.

Table 7. Conventional Equipment Configuration

1 Stage Cooling

Equipment Type DIP 1 DIP 2

1 Stage Conventional On (Up) On (Up) 2 Stage Conventional On (Up) Off (Down) 3 Stage Conventional Off (Down) On (Up)

2 Stage Cooling

Cooling Stage DIP7

1 Stage On (Up) 2 Stage Off (Down)

Table 6. Purge Damper Configuration

DIP Switch

Number

6 On (Up) Last zone(s) calling

6 Off (Down) Open all dampers

Status Purge Damper

open during Purge

during Purge

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W8835 ENVIRAZONE PANEL

Heat Pump Operation

The panel can control one or two compressor stages plus auxiliary heat. Set DIP switch 1 and 2 to Off; set DIP switch 7 to On for a single-stage compressor and to Off for a two-stage compressor.

Table 8. Heat Pump Equipment Configuration

Equipment Type DIP 1 DIP 2

Heat Pump Off (Down) Off (Down

Compressor Stages DIP 7

1 Stage On (Up) 2 Stage Off (Down

Heat Pump Changeover DIP 9

O (Cool) On (Up) B (Heat) Off (Down

Wire the reversing valve to the O/B equipment terminal. DIP switch 9 configures this terminal to operate as an O (cool) or B (heat) changeover terminal.

Hydronic Heat Operation

The W8835 is a forced air panel. However, it can be wired to control hydronic valves as shown in figure 13. To control valves or circulators on a hydronic panel, see figure 14.

Thermostat Operation

Dual Fuel Equipment

The W8835 can operate Dual fuel equipment when used with an external fossil fuel kit. Locate the thermostat on the fossil fuel kit instructions and wire the W8835 equipment terminals there.

Emergency Heat Control

Emergency heat is defined as using an auxiliary heat source without using the heat pump. The W8835 energizes the E terminal on a call for emergency heat. The thermostat system switch is set to Em Heat to engage this function. When active, any zone calling for heat uses Emergency Heat, not the compressor. The panel energizes W3 as auxiliary heat with the Y1 and Y2 for compressor control in when not in emergency heat.

Manual and Automatic Changeover Operation

Each of the thermostats can be set for manual or automatic changeover. If one or more thermostats call for cooling while one or more thermostats call for heating, the panel attempts to satisfy the greatest demand first.

Then, based on the relative demand for heating and cooling, the panel intelligently switches between heating and cooling. The system attempts to satisfy both the heating and cooling demands, and does not lock out one demand in favor of the other.

Discovery

Discovery is an automatic system configuration program where the panel configures itself to operate with controls connected to the EnviraCom bus. The panel enters Discovery when the Discovery button on the panel is pressed.

Rebooting Microprocessor

To reset the microprocessor, press and release the Boot button. The system reboots and enters the Purge mode.

EnviraCom Furnace

For furnaces with EnviraCom communications built in, configure the panel as shown below. In this case, no conventional equipment wiring is necessary because the W8835 uses the 3-wire EnviraCom bus to control the HVAC equipment. In these installations, the panel is powered from the HVAC equipment via the 1, 2, 3 wires. Because of this, the transformer R and C terminals on the W8835 are not used. Instead, leave the XFMR jumpers in their default disconnected position and wire the transformer to T1 and T2.

Table 9. Furnace Type Configuration

Type of Equipment DIP 3

Conventional On (Up) EnviraCom Off (Down)

Humidity, De-humidity and Ventilation Control

The panel can control humidity, de-humidity, and ventilation by receiving messages from the VisionPRO® IAQ thermostat. The thermostat designated as zone 1 will have control of these functions. Configure this thermostat as found in the installation instructions for the thermostat.

The humidity, de-humidity, and ventilation terminals are all drycontact terminals; the relay contacts close when active. So devices that need dry contact control like a ventilator can be wired directly to the VENT terminals, or a steam humidifier can be wired directly to the HUM terminals. Devices that need to be powered like a ventilation damper or some models of evaporative humidifiers are wired using the VENT or HUM terminals wired through the R terminal as shown in Fig. 3.

If using a Honeywell TrueSteam humidifier, configure the zone one VisionPRO IAQ thermostat installer setup #374 to "3", and wire the TrueSteam GF terminal to the HVAC fan terminal, and wire the TrueSteam GT terminal to the G on the W8835.

NOTE: When controlling a steam humidifier, set all thermo-

stats to HEAT. Do not set thermostats to AUTO. This prevents the panel from humidifying on zone 1, when another zone is calling for cooling. Alternatively, set zone 1 thermostat Installer Setup 374 to “2” to allow humidification only during calls for heat.

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