Modine Manufacturing Atherion ERM Installation And Service Manual page 8

START-UP PROCEDURE - CONTINUED
Blower Adjustments
The units are designed for ease of airflow adjustments, within
certain limits, for field balancing against actual external static
pressure conditions. If the static pressure external to the unit is
above or below the original design point for the unit, the blower
will deliver an airflow volume that is lower or higher than
required.
The blower speed (supply and/or exhaust blowers) may be
adjusted to achieve the desired air volume, provided the
adjustment is within the limits of the equipment. For supply fan
adjustments, please refer to the unit Installation and Service
Manual that shipped with the MPR unit. This section applies
only to the exhaust blower adjustment.
The motor sheave on the exhaust blower motor is adjustable to
permit adjustment of the blower speed as follows:
1. Turn off power to the unit at the disconnect switch at the
MPR unit. If the MPR unit is equipped with gas heat
option, turn all hand gas valves to the "OFF" position.
2. Loosen the belt tension and remove the belt (see Figure
8.1).
Figure 8.1 - Blower Drive Components
3. On the motor sheave, loosen the set screw on the side
away from the motor (see Figure 8.2).
Figure 8.1 - Motor Sheave Adjustment
Toward Motor
4. To increase the blower speed, turn the adjustable half of
the sheave inward. To decrease the blower speed, turn the
adjustable half of the sheave outward. The sheave half is
adjustable in ½ turn (180°) increments. Each ½ turn
represents approximately a 2-5% change in blower speed
and airflow volume.
5. Tighten the set screw on the flat portion of the sheave
shaft.
6. Replace the belt and verify that the belts are aligned in the
sheave grooves properly and are not angled from sheave
to sheave.
8
Motor Sheave
(adjustable)
Blower Sheave
(non-adjustable)
Automatic Belt
Tensioner
Set Screw
Adjustable Half
of Sheave
ATH15-520.2
7. Turn on power to the MPR unit and initiate blower motor
operation. For guidance, refer to the Controls Manual that
shipped with the MPR unit.
8. With an amp meter, check the motor amps to ensure the
maximum motor amp rating is not exceeded. Verify airflow
volume and repeat steps above for further adjustment.
9. If equipped with electric preheat, initiate preheat operation.
For guidance, refer to the Controls Manual.
10. Verify the temperature rise of the preheat section does not
exceed 50°F.
11. After 24 hours of operation, retighten the setscrews to the
torque listed in the owners manual on the bearing, sheave,
and blower wheel to avoid damage to the unit.
Optional Dirty Filter and/or Wheel Pressure Switch(es)
The optional dirty filter pressure switch and/or wheel pressure
switch is factory installed. The dirty filter pressure switch
monitors the pressure differential between the two sides of
the filters. The wheel pressure switch monitors the pressure
differential between the two sides of the wheel. When the filters
and/or wheel becomes dirty, the differential pressure increases
and trips the pressure switch which initiates an alarm from the
Carel controller. The pressure differential switch must be field
set because setting the switch requires the blower to be in
operation and the ductwork to be installed.
Setting the Pressure Switch(es)
1. Ensure that the unit filters are clean. Replace if necessary.
2. Using the Carel controller, start blower operation.
3. Turn the set screw of the pressure switch clockwise until it
stops.
4. With the wires removed from the common and normally
open terminals of the switch, measure continuity and turn
the adjustment screw counter-clockwise until the switch
makes. Then turn the adjustment screw one additional turn
counter-clockwise to account for dirty filters, wheel or other
system static changes.
Variable Frequency Drive Applications
Units may be supplied with variable frequency drives. The
minimum air flow may be varied between 50 and 100% of the
full speed air flow depending on the controls selection of the
unit, but never less than 2000CFM.
Refer to the Controls Manual for additional information.
When startup is complete, close all access doors.