Modine Manufacturing 6-558.6 - Manual (Page 10)

from the factory set performance. The drive number on the
unit may be identified by referring to the Power Code
number on the serial plate of the unit (see page 23 for
model number nomenclature) and matching that number
with those shown on page 25. From the listing the drive
number can be determined.
8. Blower sheave and motor sheave should be measured to
assure correct drive is on unit. Refer to page 25 for drive sizes.
Blower Adjustments
Following electrical connections, check blower rotation to
assure blow-through heating. If necessary, change wiring to
reverse blower rotation. Start fan motor and check blower
sheave RPM with a hand-held or strobe-type tachometer. RPM
should check out with the speeds listed in Performance Data
shown on pages 14 and 15 according to the job specifications.
A single-speed motor with an adjustable motor sheave is
supplied with these units. If blower speed changes are required,
adjust motor sheave as follows:
NOTE: Do not fire unit blower adjustment has been made or
unit may cycle on limit (overheat) control.
1. Shut-off power before making blower speed adjustments.
Refer to Determining Blower Speed on page 8 and to Blower
Drive Selection on pages 14 and 15 to determine proper
blower RPM.
2. Loosen and take belt off of motor sheave.
3. Loosen set screw on outer side of adjustable motor sheave.
(see Figure 9).
4. To reduce the speed of the blower, turn outer side of motor
sheave counterclockwise.
5. To increase the speed of the blower, turn outer side of motor
sheave clockwise.
6. Retighten motor sheave set screw, replace belt and retighten
motor base. Adjust belt tension adjusting screw such that there
is 3/4" belt deflection when pressed with 5 pounds of force
midway between the blower and motor sheaves (see Figure
9a). Since the belt tension will decrease dramatically after an
initial run-in period, it is necessary top periodically re-check the
tension to assure continual proper belt adjustment.
7. Check to make certain motor sheave and blower sheave are
aligned. Re-align if necessary.
8. Re-check blower speed after adjustment.
9. Check motor amps. Do not exceed amps shown on motor
nameplate. Slow blower if necessary.
10. Check air temperature rise across unit. Check temperature
rise against values shown in Performance Tables on pages 14
and 15 to assure actual desired air flow is being achieved.
11. If adjustments are required, re-check motor amps after final
blower speed adjustment.
Prior to Operation
Although this unit has been assembled and fire-tested at the
factory, the following pre-operational procedures should be
performed to assure proper on-site operation.
1. Turn off power.
2. Check burner to insure proper alignment.
3. Check fan clearance. Fan should not contact casing when
spun by hand.
4. Check all electrical connections to be sure they are secure.
5. If you are not familiar with the unit’s controls (i.e.
combination gas control), refer to the control manufacturer’s
literature supplied with the unit.
6. Check that all horizontal deflector blades are open a
minimum of 30° as measured from vertical.
Lighting Instructions (Also on Unit)
1. Turn off power. Turn thermostat down. Move gas control
knob (or lever) to OFF and wait 5 minutes.
2. Move gas control knob (or lever) to ON.
3. Set thermostat at desired setting. (Pilot and main burner
will light automatically when thermostat calls for heat).
Shut Down Instructions
Turn off power and close manual gas valve.
After Initial Start Up
1. Check pilot flame adjustment as discussed below.
2. Check gas piping for leaks with a soap bubble solution to
insure safe operation.
3. Check gas input rate, as described below, to assure proper
gas flow and pressure.
Figure 9
Motor Sheave Adjustment
Figure 9a
Belt Tension Adjustment
TOWARD MOTOR
SET SCREW
ADJUSTABLE HALF
OF SHEAVE
3/4" DEFLECTION
WITH 5# FORCE
TOWARD MOTOR
SET SCREW
ADJUSTABLE HALF
OF SHEAVE
10
OPERATION
CAUTION
Start-up and adjustment procedures should be performed by a
qualified serviceman.
Check the gas inlet pressure at the unit upstream of the
combination gas control. The inlet pressure should be 6"-7"
W.C. on natural gas or 11"-14" W.C. on propane. If inlet pressure
is too high, install an additional pressure regulator upstream of
the combination gas control.
The pilot flame must be adjusted as described below. Purging
of air from gas lines, piping, and lighting the pilot should be
performed as described in ANSI Z223.1-latest edition “National
Fuel Gas Code” (CAN/CGA-B149 in Canada).
Be sure no obstructions block air intake and discharge of unit
heater.
Heater Parts from ACF Greenhouses