Blower Operation And Adjustments - Lennox LGH 036 Installation Instructions Manual

FIELD WIRING REHEAT UNITS (Using A Humidity
Sensor With Less Than 150 Ft. Wire Runs)
J298A
1
A91
2
B
VIN
3
4
C
VO 2
5
6
7
GND
D
8
9
10
FIGURE 16
FIELD WIRING REHEAT UNITS (Using A Humidity
Sensor With More than 150 Ft. Wire Runs)
NOT
CONNECTED
ISOLATED 24V
TRANSFORMER
DRAIN
A91
VIN
NOT
CONNECTED
GND
VO
FIGURE 17
FIELD WIRING REHEAT UNITS
(Using A Dehumidification Switch)
J299
DEHUMIDIFICATION
SWITCH
Use 24 VAC (R) from any terminal
available on J299−2, −5, or −7.
FIGURE 18
P298
R
10
C
11
AI−1
12
HUM
TMP
DO−1
C
5
DO−2
6
DI−1
A55 UNIT
CONTROLLER
P298
J298A
1 R
2 C
B
3 AI-1
4
C
HUM
5
6
TMP
7
D
8
DO-1
9
C
10 DO-2
DI-1
7 R
8 DI−4
C
9
10

Blower Operation and Adjustments

Three-, four- and five-ton units are equipped with either
direct drive or multi-pole belt drive blowers. 6-ton units
are available with belt drive blowers only.
Three phase scroll compressors must be phased
sequentially for correct compressor and blower
rotation. Follow "COOLING START-UP" section of
installation instructions to ensure proper compres­
sor and blower operation.
A-Blower Operation
Refer to the Unit Controller Installation and Setup Guide
to energize blower. Use the menu navigation arrows and
select button; see Service - Test.
B-Determining Unit CFM
1- The following measurements must be made with air
filters in place.
IMPORTANT - On units equipped with direct drive
blowers, determine and adjust high speed CFM before
low speed CFM. Low speed CFM should be adjusted to
2/3 of high speed CFM. A low speed adjustment less than
2/3 of high speed will improve humidity removal; refer to
product data for more information.
2- With all access panels in place, measure static
pressure external to unit (from supply to return).
Blower performance data is based on static pressure
readings taken in locations shown in figure 19.
Note - Static pressure readings can vary if not taken
where shown.
3- Measure the indoor blower wheel RPM.
4- Referring to Page 16 through Page 26, use static
pressure and RPM readings to determine unit CFM.
Use Page 27 when installing units with any of the
options or accessories listed. Refer to table 3 for
minimum airflow when electric heat is installed.
MINIMUM AIRFLOW-LC UNITS WITH ELECTRIC HEAT
Kw
LCH036HE
LCH048HE
LCH060HE
Page 12
IMPORTANT
TABLE 3
(BELT DRIVE)
CFM
Downflow & Horizontal Airflow
1080
1280
1600
LGH/LCH036, 048, 060, 072