Modine Manufacturing DBP Installation And Service Manual page 21

oPtions
(20) extended grease line Zerk fittings – (oPt)
The extended grease line zerk fittings are factory installed on the
exterior corner post between the electrical and blower sections.
The zerk fittings allow pillow block bearings to be lubricated with
a grease gun. Refer to Lubrication Recommendations for
lubricant recommendations.
(21) extended grease lines – (oPt)
The extended grease lines are factory installed in the blower
section from the Extended Grease Line Zerk Fittings to the Pillow
Block Bearings. The grease lines allow the pillow block bearings
to be lubricated without requiring the service personnel to
remove both blower doors to access the bearings.
(22) return air fire stat – (oPt)
The return air fire stat is factory installed in the electrical section
with the sensor in the return air stream. In case of elevated
temperatures in the return air stream, the manual reset switch
shuts down the entire unit. If the limit temperature is exceeded,
a service person must inspect the unit for the cause of the high
discharge temperature, take corrective action, and then reset the
switch.
(23) Blower Housing – (std)
The blower housing is factory installed in the blower section.
The blower housing contains a double width, double inlet (DWDI)
blower wheel so both sides of the blower must be free from
obstructions for proper operation. For Right Hand units
(Digit 9 = R), during operation the blower wheel should rotate
in the clockwise direction when viewed from the service side of
the unit. For Left Hand units (Digit 9 = L), during operation the
blower wheel should rotate in the counterclockwise direction
when viewed from the service side of the unit. If necessary,
interchange supply power wiring to reverse blower rotation.
(24) Pillow Block Bearings – (oPt)
The blower bearings are factory installed in the blower section.
The blower can be provided with either spider or pillow block
bearings. Spider bearings are permanently lubricated and do not
require lubrication. Pillow block bearings are shipped non-
greased from the factory and require lubrication before start-up.
For lubrication recommendations, see Lubrication
Recommendations.
(25) Blower motor – (std)
The blower motor is factory installed in the blower section. The
blower motor can be provided in a variety of supply voltages,
frame types, and motor horsepowers. Refer to the model
nomenclature to determine the type of motor provided. The
blower motor is supplied with an adjustable sheave that can be
used to increase/decrease the blower RPM. For instructions on
changing the blower RPM, refer to Blower Adjustments.
(26) filters – (oPt)
When filters are supplied with the unit, a rack and the filters are
factory installed in the blower section. The unit can be supplied
with 1" or 2" permanent filters, 2" FARR ® Aeropleat MERV 7 or
2" FARR ® 30/30 MERV 8 filters. For filter replacement, refer to
Maintenance.
(27) fresh air damper – (oPt)
When a fresh air damper is supplied with the unit, the damper is
factory installed in the blower section. The fresh air damper is
used as an outside air shut-off damper, so ultra low leak, Class II
leakage resistance (less than 10 CFM/ft 2 at 1" W.C.) dampers
with self-compensating stainless steel side seals and santoprene
and galvanized steel blade seals are used.
(30) direct drive damper actuator – (oPt)
The direct drive damper actuator is factory installed in the blower
section on the side of the fresh air damper. The actuator controls
the position of the fresh air damper. The return air damper, if
provided, is controlled by the damper linkage between the two
dampers. All damper actuators are low voltage (24V). For Right
Hand units (Digit 9 = R), during operation the actuator should
rotate in the counterclockwise direction when viewed from the
service side of the unit. For Left Hand units (Digit 9 = L), during
operation the actuator should rotate in the clockwise direction
when viewed from the service side of the unit. Three different
types of dampers actuators can be provided: Two-position,
Modulating, and Floating.
Two-position Damper Actuator: A two-position damper actuator
is provided with Air Control options DA, EA, EQ, and FA (Digits
20 & 21). The two-position damper actuator provides open/
closed operation of the fresh air damper. When the damper is
energized, the fresh air damper is opened to 100% outside air in
75 seconds (For units with a two-position damper limiter, the
outside air percentage would be the set by the damper limiter.
See Two-Position Damper Limiter below). All two-position
damper actuators are spring return, so when the damper is
de-energized, the fresh air damper will spring closed. All two-
position dampers include auxiliary switches (one normally open
and one normally closed) that reverse when the damper actuator
is at 85° rotation (adjustable).
Two-Position Damper Limiter: The two-position damper limiter is
factory set to prevent the outside air damper from opening 100%.
The outside air percentage and the actuator end switch is set
based on the unit order.
Field adjustment of the two-position damper limiter is
accom plished by the following:
1. Determine the amount of damper rotation required
(Percentage of outside air).
2. Locate the angle of rotation limiter on the actuator so that its
edge lines up with the degree graduation on the actuator face
which corresponds with the required rotation. (See Figure 21.1
which is shown at 50% rotation limit.)
3. Find the appropriate cross-hair location through the slot of the
limiter. This is the screw mounting location.
4. Pierce through the label material to allow easy fastening of
the retaining screw.
5. Position the limiter back to the desired position, making sure
the locating "teeth" on the limiter are engaged into the locating
holes on the actuator.
6. Fasten the limiter to the actuator using the self tapping screw
provided.
7. Test the damper rotation either manually with the manual
crank or apply power and if required, a control signal. Re-
adjust if necessary.
figure 21.1 - two-position damper actuator and limiter
5-565.1
Lock down with screw as shown.
Adjustable end switch
set to angle of rotation
Actuator clamp at
50% rotation limit
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