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.
Equipment Type
Heat Pump
Compressor Stages
1 Stage
2 Stage
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.
Heat Pump Changeover
O (Cool)
B (Heat)
Thermostat Operation
Conventional Equipment
Conventional equipment of up to three stages of heat and two
stages of cool can be controlled by the W8835. The panel is
configured to control equipment stages using DIP switches 1, 2
and 7.
Heat Pump Equipment
Heat pump equipment with up to two heat-cool compressor
stages and auxiliary heat can be controlled by the W8835. The
panel is configured to control equipment stages using DIP
switches 1, 2, and 7.
Emergency Heat Control
Emergency heat is defined as using an auxiliary heat source
without using the heat pump. 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, on
a call for 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.
Zone of Greatest Demand
The panel designates the zone that has the highest
requirement for heat or cool as the Zone of Greatest Demand.
It is then the only zone that can energize the equipment; all
other zones receive only damper control.
68-0258ES—3
DIP 1
DIP 2
Off
Off
DIP 7
On
Off
DIP 9
On
Off
The equipment then cycles more regularly than other zone
control systems because the zone that requires conditioning
the most energizes the equipment and the other zones close
as they become satisfied. Also, more dampers are simul-
taneously open more often on calls for equipment, resulting in
less bypass damper usage and more efficient equipment
usage. All zones are satisfied; however, because if, at any
moment, another zone has a higher demand, it becomes the
Zone of Greatest Demand.
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.
Type of Equipment
Conventional
EnviraCom
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 dry-
contact 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 an evaporative humidifier
are wired using the VENT or HUM terminals wired through the
R terminal as shown in Fig. 3.
NOTE: When controlling a steam humidifier, set all thermo-
stats to either HEAT or COOL. Do not set thermostats
to AUTO. This prevents the panel from humidifying
during cooling. Alternatively, set thermostat Installer
Setup 374 to "2" to allow humidification only during
calls for heat.
10
DIP 3
On
Off