Standard Or Single Speed Fan Operation; Speed Fan Operation - Carrier WeatherMaster 50GC 04-06 Series Installation Instructions Manual

STANDARD OR SINGLE SPEED FAN OPERATION

FAN TYPE = 1SPEED is not used on 50GC units.

2 SPEED FAN OPERATION

The W7220 controller has the capability to work with a system us-
ing a 2 speed supply fan. The W7220 does not control the supply
directly but uses the following input status to determine the speed
of the supply fan and controls the OA damper to the required posi-
tion, see Table 9.
Table 9 — Fan Speed
STATE
OCC
Y1
Y2
W
DEMAND
OUTSIDE AIR
CONTROLLED
GOOD TO
VENTILATION
ECONOMIZE
(DCV)
NO
NONE
YES
NO
Below CO Set
2
YES
NO
Above CO Set
2
YES
*With stage 3 delay (STG3 DLY) in Advanced setup, COOL Y2-OUT will be turned ON after the delay time specified.
N/A = Not applicable
FAN SPEED
Low
Low
High
High
Table 10 — Economizer Operation - FAN TYPE = 2SPEED
INPUTS
W COOL
(HEAT ON) Y1-IN
ON N/A
OFF OFF
OFF ON
OFF ON
ON N/A
OFF OFF
OFF ON
OFF ON
ON N/A
OFF OFF
OFF ON
OFF ON
ON N/A
OFF OFF
OFF ON
OFF ON
ON N/A
OFF OFF
OFF ON
OFF ON
ON N/A
OFF OFF
OFF ON
OFF ON
The W (heating mode) is not controlled by the W7220 but it re-
quires the status to know where to position the OA damper for
minimum position for the fan speed.
The 2 speed fan delay is available when the system is programmed
for 2 speed fan (in the System Setup menu item). The 2 speed fan
delay is defaulted to 5 minutes and can be changed in the Ad-
vanced Setup menu item. When the unit has a call for Y1 In and in
the free cooling mode and there is a call for Y2 In, the 2-speed fan
delay starts and the OA damper will modulate 100% open, the
supply fan should be set to high speed by the unit controller. See
Table 10.
After the delay one of two actions will happen:
• The Y2 In call will be satisfied with the damper 100%
open and fan on high speed and the call will turn off
OR
If the call for additional cooling in the space has not been satisfied
then the first stage of mechanical cooling will be enabled through
Y1 Out or Y2 Out.
FAN SPEED
COOL COOL COOL
Y2-IN Y1-OUT Y2-OUT
N/A OFF OFF
OFF OFF OFF
OFF ON OFF
ON ON ON
N/A OFF OFF
OFF OFF OFF
OFF OFF OFF
ON ON OFF*
N/A OFF OFF
OFF OFF OFF
OFF ON OFF
ON ON ON
N/A OFF OFF
OFF OFF OFF
OFF OFF OFF
ON ON OFF*
N/A OFF OFF
OFF OFF OFF
OFF ON OFF
ON ON ON
N/A OFF OFF
OFF OFF OFF
OFF OFF OFF*
ON ON OFF*
34
OUTPUTS
DAMPER POSITION
(reference
OCCUPIED
only)
HIGH MIN POS H
LOW MIN POS L
LOW MIN POS L
HIGH MIN POS H
HIGH MIN POS H
LOW MIN POS L
MIN POS L to
LOW
Full Open
MIN POS H to
HIGH
Full Open
HIGH VENTMIN H
LOW VENTMIN L
LOW VENTMIN L
HIGH VENTMIN H
HIGH VENTMIN H
LOW VENTMIN L
VENTMIN L to
LOW
Full Open
VENTMIN H to
HIGH
Full Open
VENTMIN H to
HIGH
VENTMAX H
VENTMIN L to
LOW
VENTMAX L
VENTMIN L to
LOW
VENTMAX L
VENTMAX H to
HIGH
VENTMAX H
VENTMIN H to
HIGH
VENTMAX H
VENTMIN L to
LOW
VENTMAX L
VENTMIN L to
LOW
Full Open
VENTMIN H to
HIGH
Full Open
UNOCCUPIED
Closed
Closed
Closed
Closed
Closed
Closed
Closed to
Full Open
Closed to
Full Open
Closed
Closed
Closed
Closed
Closed
Closed
Closed to
Full Open
Closed to
Full Open
Closed
Closed
Closed
Closed
Closed
Closed
Closed to
Full Open
Closed to
Full Open