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V-TYPICAL OPERATING CHARACTERISTICS
A-Blower Operation and Adjustment
NOTE- The following is a generalized procedure and
does not apply to all thermostat controls.
1 - Blower operation is dependent on thermostat control
system.
2 - Generally, blower operation is set at thermostat sub
base fan switch. With fan switch in ON position, blower
operates continuously. With fan switch in AUTO position,
blower cycles with demand or runs continuously while
heating or cooling circuit cycles.
3 - Depending on the type of indoor thermostat, blower
and entire unit will be off when the system switch is in
OFF position.
B-Temperature Rise (Figure 17)
Temperature rise for ML180UHA 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
°
C” listed on the unit rating plate.
FIGURE 17
Supply Air
Return Air
TEMPERATURE RISE
Supply Duct Temperature ________
Return Duct Temperature
_
_____
Temperature Rise = ________
C-External Static Pressure
1 - Tap locations shown in figure 18 .
2 - Punch a 6.3 mm (1/4”) diameter hole in supply and re
turn air plenums. Insert manometer hose flush with in
side edge of hole or insulation. Seal around the hose
with permagum. Connect the zero end of the manome
ter 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 blow
er motor speed to deliver the air desired according to
the job requirements. For heating speed external static
pressure drop must not be more than 125Pa (0.5”). For
cooling speed external static pressure drop must not
be more than 200Pa (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)
Supply Air
Return Air
-
+
or
FIGURE 18
D-Blower Speed Taps
Blower speed tap changes are made on the integrated con
trol. See figure 4. The heating tap is connected to the
“HEAT” terminal and the cooling tap is connected to the
“COOL” terminal. On all units the continuous blower tap is
the same as the heating tap and unused taps must be se
cured on two 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.