Carrier 48MA - Manual (Page 20)

This system opens the dampers when the
indoor fans start. To keep them closed, short
across the W-R terminals on the remote control
panel or the “Short To Close Dampers” terminals
during the NS period.
METHOD NO. 3 -- USING ACCESSORY RE­
MOTE PANEL, HEATING AND COOLING
NIGHT SETBACK AND INDOOR FAN CYCLING
This system requires a:
Carrier remote control panel assembly
48MA900041
Carrier heating and cooling thermostat
HH07AT074
Carrier subbase HH93AZ070
Night setback relay (Honeywell fan center
R8227A)
Seven-day timer (Honeywell S659A)
The system (Fig. 22) is a proposed heating and
cooling niglrt setback with fan cycling. The
thermostat is a standard Carrier part with no
switches on the subbase. This requires a NS relay
with normally closed contacts so an alternate,
Honeywell R8227A is required.
Because cooling is not locked out, the clock
switches that close at niglit are used to directly
close the outdoor air dampers by connecting across
R and W on the remote panel accessory. Again the
MUR shuts down the unit (including the indoor
fans). When the NS thermostats reach their set­
tings, the NS relay is energized, opening the NC
contacts and de-energizing the MUR.
However, if a “wild” zone exists, it is allowed
to cool on heating NS or vice versa. This may be an
advantage on some applications between zones.
Again when the day/night is switched to
“Day,” the NS is overridden and the unit operates
normally except the dampers remain closed at
night.
SWITCHES SHOWN IN NIGHT POSITION,
V 'T "V
NOTE: 24V WIRING
BETWEEN CONTROLS
NIGHT SETBACK
RELAY
LEGEND
APS — Air Pressure Switch
FRS — Filter Media Runout
Switch
MCR — Master Cooling Relay
MHR — Master Heating Relay
MUR — Mastei Unit Relay
TC — Thermostat, Cooling
TH — Thermostat, Heating
c=.OR® Terminal (Circuit Board,
Field or Accessory Conn )
_______ Accessory or Field Wiring
________ Factory Wiring
' Circuit Board Run
FILTER
<3F-ri-]-i-g
XI
. . ¿ X I c 3 x 2
TO REMOTE PANEL
MHR .
=*=o4
MUR I MUR I
-0==j=O=I
MCR |_MCRj I
l 2 j l I_ i
O) SHORT TO HI H2
^ CLOSE DAMPERS
0
ACCESSORY BOARD
ON BASE UNIT
REMOVE JUMPERS
BETWEEN NC ANDR; CANDW
#
Fig. 22 — Night Setback, Method #3
18