Electrical Connections; Start-Up Procedure; Not Exceed Or Fall Below The Rated Input Voltage By More Than - Modine Manufacturing MT28 Installation And Service Manual

INSTALLATION / START-UP PROCEDURE

Electrical Connections

WARNING
Disconnect power supply before making wiring connections to
prevent electrical shock and equipment damage.
All units must be wired strictly in accordance with wiring
diagram furnished with the unit. Any wiring different from the
wiring diagram could result in a hazard to persons and
property.
Any original factory wiring that requires replacement must be
replaced with wiring material having a temperature rating of at
least 105°C.
To prevent gas control circuit malfunction, the voltage to the
unit, as indicated on the serial plate, must not exceed or fall
below the rated input voltage by more than 5%.
1. Installation of wiring must conform with local building codes,
or in the absence of local codes, of 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. The power supply to the unit should be protected with a
fused disconnect switch.
3. Provide only the voltage to the heater as stamped on the
heater serial plate. Do not provide external power to a
heater equipped with a millivolt, self-energizing control
system (Control Codes 27 or 67).
4. Heaters equipped with 25V controls (Control Codes 04, 48,
or 75) require a step-down transformer having a VA rating
in excess of the total connected electrical load.
5. The heater is not to be energized until gas is available at
the heater. Failure to observe this point may result in failure
of control components.
6. Wiring must not be located directly above or below the
heater to avoid overheating of the wires. The wires must
not touch the sides of the heater.
7. Control wire used to connect the heater to the thermostat
must have adequate ampacity and insulation temperature
rating for the total connected load.
6

START-UP PROCEDURE

CAUTION
Purging of air from gas lines should be performed as
described in ANSI Z223.1 - Latest Edition "National Fuel Gas
Code", or in Canada, CAN/CGA-B149 codes.
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 the
unit has been wired according to the wiring diagram.
3. Verify that there is adequate ventilation for intake of fresh
air and exhaust of products of combustion.
4. Perform a visual inspection of the unit to make sure no
damage has occurred during installation.
5. Recheck the gas supply pressure. The inlet pressure to the
unit must be 7-14" W.C. for natural gas and 11-14" W.C. for
propane gas. The gas supply pressure must never exceed
14" W.C. If the pressure exceeds 14" W.C., a gas pressure
regulator must be added upstream of the combination gas
valve.
6. Open the field installed manual shut-off valve and turn
power on to the unit.
7. Follow the procedure on the heater's Lighting Instruction
Label to put the heater into operation. Be certain the gas
line is purged of air prior to attempting to operate the unit.
8. For units equipped with a pilot, check the pilot flame length
(See Pilot Flame Adjustment section).
9. Check to make sure that the main gas valve opens upon a
call for heat from the thermostat.
10. Check to insure that gas controls sequence properly (See
Control Operating Sequence, page 8).