Modine heaters are unit heaters generally used to heat garage or warehouse space. These heaters burn natural gas, which heats up a component known as a heat exchanger. A fan blows air across the heat exchanger, and as a result the air warms. Wiring a Modine heater will require you to run an 120-volt electrical wire from a power source to the heater and a low-voltage thermostat wire from the thermostat to the heater.
Turn off the power to the heater. The best way to do this is to turn the corresponding circuit breaker off.
Open up the electrical access cover on your Modine heater. Strip your electrical wiring so that you have about 1/2 an inch of bare wire exposed on your black and white leads.
Slide your electrical wiring into the electrical box on the heater. Secure the wiring with an electrical clamp.
Twist the black lead from your electrical wiring with the black lead on the heater. Twist the white lead from your electrical wiring with the white lead on the heater. Screw a wire nut on each lead. Fasten the ground (green) lead to the green screw. Reattach the electrical cover plate.
Strip your thermostat wiring to expose 1/2 an inch of wire on each of the two leads.
Locate the terminal strip on the back of the heater. Usually it will be located near the electrical connection you made above.
Attach the red thermostat wire to the "R" terminal on the Modine heater. Attach the white wire to the "W" terminal on the heater.
Turn the power on to the circuit and test your heater with its associated thermostat.