Start-Up Procedure/Operation - Modine Manufacturing HD Manual

START-UP PROCEDURE
IMPORTANT
1. To prevent premature heat exchanger failure, observe
heat exchanger tubes. If the bottom of the tubes become
red while blower and furnace are in operation, check to
be sure the blower has been set to the proper rpm for the
application. Refer to page 14 for blower adjustments.
2. Start-up and adjustment procedures must be performed by
a qualified service agency.
1. Turn off power to the unit at the disconnect switch. Check
that fuses or circuit breakers are in place and sized
correctly. Turn all hand gas valves to the "OFF" position.
2. Remove electrical junction box cover.
3. Check that the supply voltage matches the unit supply
voltage listed on the Model Identification Plate. Verify that
all wiring is secure and properly protected. Trace circuits to
insure that the unit has been wired according to the wiring
diagram. If installed at altitudes above 2,000' and the high
altitude kit includes a combustion air proving switch, replace
the switch in the unit with the switch provided in the kit. Take
care to ensure that the tubing and electrical connections are
securely fastened.
4. Check to insure that the venting system is installed correctly
and free from obstructions.
5. Check to see that there are no obstructions to the intake
and discharge of the unit.
6. For blower units, check the belt tension and sheave
alignment. Refer to "Blower Adjustments" for proper belt
tension.
7. Check bearings for proper lubrication (if applicable).
8. Check to make sure that all filters are in place and that
they are installed properly according to direction of air flow
(if applicable).
9. Perform a visual inspection of the unit to make sure no
damage has occurred during installation. Lower bottom pan
and visually inspect all components in the burner
compartment. Check to ensure all fasteners are in place
and the burner openings are properly aligned with the heat
exchanger tubes and that the gas orifices are centered in
the burner inspirator tube opening, as shown in Figure 16.2.
10. Check that all horizontal deflector blades are open a
minimum of 30° as measured from vertical.
11. Turn on power to the unit at the disconnect switch. Check to
insure that the voltage between electrical junction box
terminals T1 and G is 24V.
12. Check the thermostat, ignition control, gas valve, and supply
fan blower motor for electrical operation. If these do not
function, recheck the wiring diagram. Check to insure that
none of the Control Options have tripped.
1 3. Check the blower wheel for proper direction of rotation
when compared to the air flow direction arrow on the
blower housing (if applicable). Blower wheel rotation, not air
movement, must be checked as some air will be delivered
through the unit with the blower wheel running backwards.
14. For blower units, check the blower speed (rpm). Refer to
"Blower Adjustments" for modification.
15. Check the motor speed (rpm).
16. Check the motor voltage. On three phase systems, check to
make sure all legs are in balance.
17. Check the motor amp draw to make sure it does not exceed
the motor nameplate rating. On three phase systems, check
all legs to insure system is balanced.
18. Recheck the gas supply pressure at the field installed
manual shut-off valve. The minimum inlet pressure should
be 6" W.C. on natural gas and 11" W.C. on propane gas.
The maximum inlet pressure for either gas is 14" W.C. If
inlet pressure exceeds 14" W.C., a gas pressure regulator
must be added upstream of the combination gas valve.
19. Open the field installed manual gas shut-off valve.
20. Open the manual main gas valve on the combination gas
valve. Call for heat with the thermostat and allow the pilot to
light for intermittent pilot ignition. If the pilot does not light,
purge the pilot line. If air purging is required, disconnect the
pilot line at outlet of pilot valve. In no case should line be
purged into heat exchanger. Check the pilot flame length
(See "Pilot Flame Adjustment").
21. Once the pilot has been established, check to make sure
that the main gas valve opens. Check the manifold gas
pressure (see "Main Gas Adjustment") and flame length
(see "Air Shutter Adjustment") while the supply fan blower
is operating. Inspect the condition of the main flame and
if necessary, resolve flame appearance problems (see
"Burner Flame Adjustment" and Figures 28.1 through 28.4).
22. Check to insure that gas controls sequence properly (see
"Control Operating Sequence"). Verify if the unit has any
additional control devices and set according to the
instructions in the "Control Options".
23. Once proper operation of the unit has been verified,
remove any jumper wires that were required for testing.
24. Replace the electrical junction box cover.
25. If installed at altitudes above 2,000', affix label included with
high altitude kit and fill in all fields with a permanent marker.
Pilot Burner Adjustment
The pilot burner is orificed to burn properly with an inlet
pressure of 6-7" W.C. on natural gas and 11-14" W.C. on
propane gas, but final adjustment must be made after
installation. If the pilot flame is too long or large, it is possible
that it may cause soot and/or impinge on the heat exchanger,
causing failure. If the pilot flame is shorter than shown, it may
cause poor ignition and result in the controls not opening the
combination gas control. A short flame can be caused by a
dirty pilot orifice. Pilot flame condition should be observed
periodically to assure trouble-free operation.
To Adjust the Pilot Flame
1. Create a call for heat from the thermostat.
2. Remove the cap from the pilot adjustment screw. For
location, see the combination gas control literature supplied
with unit.
3. Adjust the pilot length by turning the screw in or out to
achieve a soft steady flame 3/4" to 1" long and
encompassing 3/8"-1/2" of the tip of the thermocouple or
flame sensing rod (see Figure 15.1).
4. Replace the cap from the pilot adjustment screw.
Figure 15.1 - Correct Pilot Flame
6-580.18
3/4" to 1"
15