Does this heater need to run on 220 - Hayward 400FDP Universal Series Low Nox Propane Heater 400000 BTU ()

only getting one side of the 220 so half the heat

10-2 is for 220. White is neutral and black is power. You'll have to run a 10 gauge wire to the heater from your panel. Probably a good idea to hire an electrician as you make need to have a breaker added to your panel...could check/install if you need a wall thermostat. 220 is dangerous....

1) bad thermostats. There are usually 2 or more. A high limit on heater box, just above terminals on the bottom. 1 or 2 will be on the duct next to the blower. Check these with an ohm meter (or continuity checker). Some have 4 terminals, the extra 2 small terminals are small heaters inside the thermostats which alter it's temperature characteristics. These will usually read around 4000 ohms or so. Check the 2 main largest terminals for continuity.

2) Only getting 110 volts: This is often overlooked, but if for some reason one of the poles feeding the 220 power from the house wiring is open but the other is OK (for example, houses with fuses where only one fuse is blown, or a bad circuit breaker with one pole open). The motor and timer run on 110. If the side of the 220 line that feeds the motor is OK but the other one is open the motor will run but the heater,( which needs 220), will not heat. Check for 220 volts between the 2 outer terminals where power cord connects or between the 2 "hot" terminals of the 220 outlet the dryer is plugged into.

3) Bad centrifugal switch in motor. This is what actually turns the heater on, for safety reasons, so the heater cannot come on unless the fan is spinning. Otherwise without air flow past it, the heater would burn out. There are 2 large gauge (usually red or yellow) wires going to the connector on the motor, these go to the contacts inside the motor that turn the heater on.

Hope this helped Tim

Links below show specific wiring diagrams and explain 240V with two hot wires vrs 120V with hot and neutral wires.

Then if you have more questions, add a comment and I will fill in blanks:
http://waterheatertimer.org/How-to-wire-water-heater-thermostats.html
First diagram will be for your water heater.

http://waterheatertimer.org/B220C.html

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Greetings,

Unplug the dryer first for safety sake....remove rear cover and use an ohm meter to check the value of your heater and your safty thermostat....this dryer runs on 220 volts, but if only getting 110..it will still run, but heater will not come on....i suggest to check for voltage at terminal block...it should be 220...if not, check breaker or fuses getting back to heater element and thermal...check these and if bad, replace

I have seen the motor switch be bad and the timer as well...both these will cause a no heat problem...bet its the heater thermal or heater

220 is getting into the hot range but that doesn't sound like your problem. It sounds like your blend door in your air distribution box is acting up and not switching. Or you might have a blockage in your heater core, control valve, or hoses. Make sure you have enough coolany and are not just pushing steam through the heater core before anything else.

all depends on the wattage of the heaters. add up the wattage of the heaters divide that answer by 220 and that will give you your amperage draw, then you must size your wire, breaker and outlet accordingly. you can only load a braker to 80 percent of its amperage by the CEC.

Here is a link to the manual for the RS4.

check for continuity in the thermal fuse, also check heating element. make sure you have disconnected the power first. if this is a 220 volt machine make sure you are getting 220 to the machine. if one leg of the voltage has dropped out the motor will run but unit will not heat