Lennox KHA SERIES, Manual

Page: 39 / 49

Page 39
TABLE 13
ECONOMIZER OPERATION
OUTDOOR AIR IS SUITABLE FOR FREE COOLING −− FREE COOL LED ON"
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
THERMOSTAT DEMAND
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
DAMPER POSITION
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
MECHANICAL COOLING
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
UNOCCUPIED
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OCCUPIED
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
OFF
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
CLOSED
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
CLOSED
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
NO
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
G
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
CLOSED
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
MINIMUM
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
NO
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
Y1
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
NO
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
Y2
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
STAGE 1
*Dampers will modulate to maintain 55
_
F (13
_
C) supply air when an R1 mixed air sensor is installed.
FIGURE 21
POWER EXHAUST FAN
P18
J18 JACK ON
UNDERSIDE OF
DIVISION PANEL
CONNECT P18 TO J18
BEFORE SECURING
EXHAUST FAN IN
PLACE
F−Power Exhaust Relay K65 (PED units)
Power exhaust relay K65 is a N.O. DPDT relay with a
24VAC coil. K65 is used in all KHA units equipped with
the optional power exhaust dampers. K65 is energized
by the economizer control panel (A6), after the econo-
mizer dampers reach 50% open (adjustable on control
A6). When K65 closes, the exhaust fan B10 is ener-
gized.
G−Power Exhaust Fans
T1PWRE10A available for KHA036, 048 units and
T1PWRE10N available for 060 units, provide exhaust air
pressure relief and also run when return air dampers are
closed and supply air blowers are operating. See figure 21
and installation instructions for more detail.
H−Dirty Filter Switch S27
The dirty filter switch senses static pressure increase indi-
cating a dirty filter condition. The switch is N.O. and closes
at 1" W.C. (248.6 Pa) The switch is mounted in the filter sec-
tion on the left unit mullion.
I−Indoor Air Quality (CO
2
) Sensor A63
The indoor air quality sensor monitors CO
2
levels and re-
ports the levels to the economizer enthalpy control A6.
Controller A6 adjusts the economizer dampers according
to the CO
2
levels. The sensor is mounted next to the in-
door thermostat or in the return air duct. Refer to the in-
door air quality sensor installation instructions for proper
adjustment.
J−Drain Pan Overflow Switch S149 (optional)
The overflow switch is used to interrupt cooling opera-
tion when excessive condensate collects in the drain
pan. The N.O. overflow switch is controlled by K220 and
DL46 relays, located in the unit control panel. When the
overflow switch closes, 24VAC power is interrupted and
after a five−second delay unit compressors are de−ener-
gized. Once the condensate level drops below the set
level, the switch will open. After a five−minute delay the
compressor will be energized.