40
2-1/64 (55)
51/64 (21)
4-1/4 (108)
2-3/4 (70)
NOTE: Dimensions are in inches. Dimensions in ( ) are in mm.
a50--- 9614
Fig. 52 -- Enthalpy Control Sensor, Dimensions and
DIP Switch Location
Table 11 – Enthalpy Control Sensor
Wiring Terminations*
Term i nal
Type Description
Nbr Label
1 S --- B U S S --- B U S
S --- B u s C o m m u n i c a t i o n s
(Enthalpy C ontrol Sensor Bus)
2 S --- B U S S --- B U S
S --- B u s C o m m u n i c a t i o n s
(Enthalpy C ontrol Sensor Bus)
* Terminals are polarity insensitive.
Table 12 – Enthalpy Control Sensor DIP Switch Settings
Use
DIP Switch Positions for Switches 1, 2, and 3
1 2 3
DA OFF ON OFF
RA ON OFF OFF
OA OFF OFF OFF
Legend
DA = Discharge Air
RA = Return Air
OA = Outside Air
When a S--bus sensor is connected to an existing network,
it will take 60 minutes for the network to recognize and
auto--configure itself to use the new sensor. During the 60
minute setup period, no alarms for sensor failures (except
SAT) will be issued and no economizing function will be
available.
Operating Sequences
Staged Air Volume (3--Speed) Fan Motor —
The Integrated Staging Control (ISC) Board in the main
unit determines the operating speed (LOW/MED/HIGH)
of the indoor fan based on space thermostat demand
conditions. See Table 13 for this logic.
Table 13 – Supply Fan Speed Logic without Economizer
TSTAT
OUTPUT
G/OCC 0 --- V 2 4 --- V 0 --- V 0 --- V
Y1 0 --- V 2 4 --- V 0 --- V 0 --- V
Y2 0 --- V 0 --- V 2 4 --- V 0 --- V
Y3 0 --- V 0 --- V 0 --- V 2 4 --- V
W1 0 --- V 0 --- V 0 --- V 2 4 --- V
W2 0 --- V 0 --- V 0 --- V 2 4 --- V
SUPPLY
FAN
MOTOR
SPEED
OFF LOW MED HIGH
W7220 Economizer Control —
Tables 14 and 15 provide the W7220 Input/Output L ogic.
Table 14 describes economizer functions for a unit
without a CO
2
sensor. Table 15 describes economizer
functions for a unit with Demand Controlled Ventilation
(CO
2
sensor connected). The supply fan speed is i ncluded
in t hese tables for reference; this is neither an input or
output of the W7220 controller.
Base Unit Controls —
Base unit includes standard electromechanical controls,
Staged Air Volume (3--speed supply fa n motor with VFD),
EconoMi$e r
R
X (with W7220 controller) and thermostat
or unitary controller that energizes the G terminal in
cooling and heating to control the supply fan operation.
Cooling, Unit With EconoMi$er X Without CO
2
Sensor —
For Occupi ed mode operation of the EconoMi$er X
control, there must be a 24--v signal at terminal G at the
unit’s Integrated Sta ging Control Board from the
thermostat; supply fan motor will start and run in Low
Speed. The signal at G is connected to W7220 input OCC,
plac ing the EconoMi$er X control in Occupied mode; the
econom izer actuator is commanded open to the MIN POS
L ventilation position. Removing the signal at OCC places
the EconoMi$er X control in Unoccupied mode; the
economizer actuator is driven back to full--closed position.
When free cooling using outside air is not avail able, the
unit cooling sequence will be controlled directly by the
space thermostat. Thermostat call for Stage 1 Cooling
energizes ISC terminals G and Y1; supply fan m otor sta rts
and runs in Low Speed. The Y1 demand is received at
W7220 terminal Y1--I. Outside a ir damper position will be
at MIN POS L. W7220 output Y1--O is energized; first
stage mechanical cooling starts.
As space temperature falls and space cooling load is
satisfied, the thermostat will remove its call for first stage
cooling; ISC terminal Y1 call is removed. The W7220
input Y1--I is removed; output Y1--O is de--energized,
stopping fi rst stage cooling.
When ISC terminal Y1 is de--energized, terminal G may
remain energized, indicating Continuous Fan operation.
To Next Page
Loading...
