I have a Dayton 3UG73D heater that I need to hook up. I have a 220V line in the garage, red,black,white, and a ground. The line comes out of the breaker box from two 20amp breakers. The Dayton heater has only a 3 wire hookup, ie black, white, and ground. This is a residential installation. How do I connect? I would like to put an outlet on the garage line so that I can unplug the heater in the summer but three wire plugs have a different prong pattern than the four wire outlets.

Did you turn the breaker back on after connection , also is there a thermostat with this heater?.

220 - 240 volt, 60 hertz, properly grounded circuit with 40 amp breaker or fuse protection with #8 gauge wire. For Electric Heaters.

Your 220v hot water heater does not need the neutral(white) wire coming in. Bare wire goes to ground -green headed screw. Black goes to black, Red goes to red. White gets teminated with a wirenut or some electrical tape.

Check for loose or disconnected wire especially to the hi-limit switch or fan switch.

is this a baseboard unit? the thermostat kit has four wires - a black and a red, a black and a red. for 240 volt operation, both line wires go on the two blacks and the heater load goes on the red wires

if you have a electric meter check the voltage coming out of the wall to be sure it is 220 v???? (meter across black and white)then with your meter only test black wire to ground and white wire to ground seperately you should have 110 from each wire to ground?
If you have only 110 to the black and no reading on the white, you either have a bad breaker or a 110v circuit
If you read 220v and you new heater is rated for 220v black to black and red to white wall thermostat or built in as long as you have 220v to your connection from the wall or your wall thermostat when turned higher than room temp.
Bare grounds tie together and mount to your green ground screw

No, as long as the heater on the label says 240 volts. You would hook up your 240 v to black and white wire

The white is the common neutral, it is probably a 3 wire unit, and you are missing the ground wire. Check inside the control panel and see if someone wired it using the white wire for the ground, it will be screwed into a terminal lug. Check the schematics to see if the unit requires a common neutral to run the controls.

need to check you fan wires, some have differant colors on the moter for the differant speeds, you may need to change the fan speed by unplugging one of the wires and replacing it with another. hopefully you still have the manuel , check with it first!!!

Red wire is not needed. Be certain 208 volts is read across black and white. Cap off the red.