Page 23
B-Temperature Rise (Figure 22)
Temperature rise for ML180DFE units depends on unit in
-
put, blower speed, blower horsepower and static pressure
as marked on the unit rating plate. The blower speed must
be set for unit operation within the range of “TEMP. RISE
°F” listed on the unit rating plate.
Return
Supply
Temperatures
TEMPERATURE RISE
Supply Duct Temperature
Return Duct Temperature
_
Temperature Rise =
FIGURE 22
C-External Static Pressur
1 -
Tap locations shown in figure 23 .
2 - Punch a 1/4” diameter hole in supply and return
air plenums. Insert manometer hose flush with
inside edge of hole or insulation. Seal around the
hose with permagum. Connect the zero end of the
manometer to the discharge (supply) side of the
system. On ducted systems, connect the other end
of manometer to the return duct as above.
3 - With only the blower motor running and the
evaporator coil dry, observe the manometer
reading. Adjust blower motor speed to deliver the
air desired according to the job requirements. For
heating speed external static pressure drop must
not be more than 0.5” W.C. For cooling speed
external static pressure drop must not be more than
0.8” W.C.
4 - Seal the hole when the check is complete.
EXTERNAL STATIC PRESSURE
Supply Duct Static
Return Duct
Total Duct Static =
(dry coil)
Return
Supply
High “+”
Low “-”
+
−
or
FIGURE 23
D-Blower Speed Taps
Blower speed tap changes are made on the integrated
control. See figure 3. The heating tap is connected to the
“HEAT” terminal and the cooling tap is connected to the
“COOL” terminal. The continuous blower tap is connected
to the “FAN” terminal. Unused taps must be secured on
dummy terminals labeled ”PARK. To change out existing
speed tap, turn off power and switch out speed tap with
tap connected to “PARK”. See blower speed tap table on
unit diagram for motor tap colors for each speed.
VI-MAINTENANCE
Annual Furnace Maintenance
At the beginning of each heating season, and to comply
with the
Lennox Limited Warranty,
your system should
be checked by a licensed professional technician (or
equivalent) as follows:
1 -
Check wiring for loose connections, voltage at
indoor unit and amperage of indoor motor.
2 - Check the condition of the belt and shaft bearings
if applicable.
3 - Inspect all gas pipe and connections for leaks.
4 - Check the cleanliness of filters and change if
necessary (monthly). See table 15.
