Reznor MAPS - A,B,C Users Manual - Manual (Page 24)

Form O-MAPSIII&IV Cabinets A/B/C, Page 24
4.1.2 Maintenance Instructions for the Venter Motor and Wheel
Follow the instructions below to remove the venter assembly. Keep all hardware
removed to be used in re-assembling and installing the replacement parts.
Note that during normal operation of this deep modulation control system, the cur-
rent draw of the venter motor can exceed the full load amp rating on its nameplate.
This condition is common when employing electronic wave-chopping technology to
reduce the running speed of a single-phase type PSC alternating current motor. The
technology reduces energy to the main winding by momentarily interrupting current for
a variable amount of time, resulting in a reduction of the motor speed. The increased
current is a result of increased slip, which is the difference between the rotation speeds
of the rotor and stator fields. All motors used in MAPS ® systems are custom designed
and built for this unique modulating application and cannot be replaced with a non-
approved motor. All prototype motors have been thoroughly tested with regards to tem-
perature of the windings and bearings at all operating points and ambient conditions
and approved by the manufacturer to assure the elevated current does not affect the
normal motor life expectancy.
Instructions:
1. Turn off the gas and disconnect the electric power.
2. Open the gas heat section access panel and the electrical compartment.
3. Disconnect the three venter motor wires at the control board, capacitor wires at the
capacitor (if applicable), and ground screw (located on the control panel).
4. Holding the venter motor, remove the three or four screws that attach the venter
motor and wheel assembly. Remove the motor and wheel assembly.
5. Re-assemble with the replacement venter motor and wheel assembly. See
FIGURE 13, for proper spacing.
6. Follow the wiring diagram to re-connect the venter wires.
7. Close the access panels. Restore power to the gas heater and turn on the gas.
Check for proper operation.
NOTE: Manufacturer
recommends replacing
venter motor capacitor
when replacing venter
motor. Use only factory-
authorized replacement
parts.
1/2” (13mm) from motor
plate to wheel
NOTE: Measure from
plate and not the gasket.
Venter
Motor
Motor Plate
with Gasket
Venter Wheel
FIGURE 13 - Venter
Wheel Position on
the Shaft
4.1.3 Re-Assemble
the Heat Exchanger
Panel, Burner, Gas
Train, and Venter
Instructions to Re-Assemble the Gas Heat Section (Refer back to
FIGURES 10 and 11.)
1. Re-attach the Burner Assembly - Slide the entire burner assembly into position.
Insert all of the screws along the top and the bottom.
2. Re-attach the Gas Train - Position the gas train so that the orifice adapter(s) are
through the brackets. Attach the manifold to the manifold brackets. Install the
orifice adapter nuts and the gas orifice(s) being careful not to damage the venturi
tubes and/or the brackets. Re-connect the wires to the gas valve.
3. Re-attach the venter assembly. (If replacing venter parts, follow the instructions
above.) Re-connect the tubing and the wires.
4. Close the access panel.
5. Reconnect the gas supply at the union outside of the cabinet. Leak test the
connection with leak detecting solution. Turn on the electric. Turn on the gas.
Check for proper operation.
4.0 Gas Heat
Section
Maintenance
(cont'd)
4.1 Heat Exchanger,
Burner,
and Venter
Maintenance
(cont'd)
If replacing venter parts, see FIGURE 3 for proper spacing. If the motor plate gasket
is damaged or deteriorated, replace it with P/N 222856.
Remove dirt and grease from the venter housing, the motor casing, and the venter
wheel. Venter motor bearings are permanently lubricated.