Electrical Connections; Start-Up Procedure - Modine Manufacturing DFP Installation And Service Manual

INSTALLATION / START-UP PROCEDURE

Electrical Connections

WARNING
1. Disconnect power supply before making wiring connections
to prevent electrical shock and equipment damage.
2. All appliances must be wired strictly in accordance with
wiring diagram furnished with the appliance. Any wiring
different from the wiring diagram could result in a hazard
to persons and property.
3. Any original factory wiring that requires replacement must
be replaced with wiring material having a temperature
rating of at least 105°C.
4. Ensure that the supply voltage to the appliance, as indicated
on the serial plate, is not 5% greater than rated voltage.
CAUTION
Ensure that the supply voltage to the appliance, as indicated
on the serial plate, is not 5% less than rated voltage.
1. Installation of wiring must conform with local building codes,
or in the absence of local codes, with the National Electric
Code ANSI/NFPA 70 - Latest Edition. Unit must be electrically
grounded in conformance to this code. In Canada, wiring
must comply with CSA C22.1, Part 1, Electrical Code.
2. All duct furnaces are provided with a wiring diagram located
on the inside door of the electrical junction box. Refer to this
wiring diagram for all wiring connections. For factory installed
options and field installed accessory wiring, refer to Set A and
Set B on the provided wiring diagram.
3. The power supply to the duct furnace should be protected
with a fused disconnect switch.
4. Refer to Table 9.1 to determine the amp draw of the duct
furnace by adding the amp draw for the control transformer
(includes ignition controllers, gas valves, control relays, and
amplifiers) and power exhauster together, based on the
voltage and model size. Size the disconnect switch to cover
the amp draw of the unit.
5. Refer to the unit dimensional drawing on page 15 for the
electrical knockout locations.
Table 9.1 - Unit Amps
Control Step Down
Digit 14
Transformer Amp Draw
Digit 15 - Transformer
Supply Voltage
0 ➀
1
115/60/1 0 0.35
A
B 208/60/1 0 0.19
C 230/60/1 0 0.17
D 208/60/3 0 0.19
E 230/60/3 0 0.17
460/60/3 ➃
F 0 0.09
575/60/3 ➃
G 0 0.07
➀ Unit controls amp draw is included in master unit amp draw.
➁ Requires a 250 VA transformer.
➂ Requires a 500 VA transformer.
➃ For Digits F (460V) and G (575V), amp draw shown is on primary (line) side of
required step-down transformer.
Power Exhauster
Amp Draw
Model Size
2 3 4 75-175 200-400
0.65 1.3 2.17 1.4
0.36 0.72 1.2 0.7
0.33 0.65 1.09 0.6
0.36 0.72 1.2 0.7
0.33 0.65 1.09 0.6
0.30 ➁ 0.65 ➂
0.16 0.33 0.54
0.24 ➁ 0.52 ➂
0.13 0.26 0.43

START-UP PROCEDURE

IMPORTANT
Start-up and adjustment procedures should 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. Check that the supply voltage matches the unit supply
voltage listed on the serial 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.
3. Check to insure that the venting system is installed and free
from obstructions.
4. Check to see that there are no obstructions to the intake
and discharge of the duct furnace.
5. Perform a visual inspection of the unit to make sure no
damage has occurred during installation.
6. Turn on power to the unit at the disconnect switch. Check to
insure that the voltage between terminals 1 and 2 is 24V.
7. Check the thermostat, ignition control, gas valve, power
exhauster motor, and supply fan blower motor for electrical
operation. If these do not function, recheck the wiring
diagram. Check to insure that none of the Gas Control
Options & Accessories (see page 14) have tripped.
8. Recheck the gas supply pressure at the field installed
manual-shut-off valve. The inlet pressure should be 6"-7"
W.C. on natural gas and 11"-14" W.C. on propane gas.
If inlet pressure is too high, install an additional pressure
regulator upstream of the combination gas control.
9. Open the field installed manual gas shut-off valve.
10. Open the manual main gas valve on the combination gas
control. Call for heat with the thermostat. On a call for heat,
the power exhauster relay will energize the power exhauster
motor. Once the power exhauster motor has reached full
speed, the differential pressure switch will close. Once
closed, the ignition controller will attempt to light the pilot.
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 the line be purged into heat exchanger.
Check the pilot flame length (See Pilot Burner Adjustment).
11. Once the pilot has been established, check to make sure
that the main gas valve opens. Check the manifold gas
pressure (See Main Burner Adjustment) and flame length
(See Air Shutter Adjustment) while the circulating air blower
is operating.
12. 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 Gas Controls Options.
13. Once proper operation of the duct furnace has been
2.4
verified, remove any jumper wires that were required for
1.4
testing.
1.3
14. Close the electrical compartment door.
1.4
1.3
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