Lennox LCH036 Installation Instructions Manual page 135

C-Supply Air VFD By-Pass (Optional)
IMPORTANT - All dampers must be open to prevent
damage to duct work and dampers.
1- Turn off all power to unit.
2- Locate J/P246, J/P247, J/P248 and J/P249
connectors near the VFD. See figure 30.
3- Disconnect P246 from J246 and connect P249 to
J246. See figure 27.
SUPPLY AIR VFD BY-PASS CONNECTOR
Disconnect
P246
J246
FIGURE 27
4- Disconnect P247 from J247 and connect J249 to
P247. See figure 28.
SUPPLY AIR VFD BY-PASS CONNECTOR
Disconnect
P247
J247
FIGURE 28
5- Disconnect J248 from P248 and connect connect
P248 jumper plug to J248. P248 jumper plug is
attached to the J248 wire harness near the J248 jack
connector. See figure 29.
SUPPLY AIR VFD BY-PASS CONNECTOR
Disconnect
P248
J248
FIGURE 29
6- Locate VFD control relay K203 on the lower control
panel next to terminal strip TB24. See figure 30.
Connect
P249
J246
Connect
P247
J249
Connect
P248
Jumper
Plug
J248
Page 35
SUPPLY AIR VFD BY-PASS COMPONENTS
FIGURE 30
7- Remove the female receptacle terminal from K203
terminal A.
8- Locate the male tab terminal near K203. Connect
male tab terminal to the female receptacle terminal
removed in previous step.
9- Restore power to unit. Blower will operate in constant
air volume (CAV) mode.
10- Check the indoor blower motor nameplate for full load
amperage (FLA) value. Measure the amp readings
from the indoor blower motor operating in bypass
mode. If measured amps are higher than nameplate
FLA value, decrease the CFM by opening (turning
counterclockwise) the motor pulley. See figure 14. Do
not exceed minimum and maximum number of pulley
turns as shown in table 3.