I am installing a Mr. Heater MHU 50. I have the gas and thermostat ran. I am now about to run the electrical to a dedicated circuit using 14/2 wire to a 15 amp breaker. The run is no more than 12’. Anyone see a problem with what I have so far? This is my first time at doing something like this so any help or criticism is appreciated.
Mr Heater install
- Thread starter tc_rain
- Start date
dave67fd
Well-known member
Obviously the vent and It looks like you may have a service swich on the rear of the unit. If not I would replace the plug and outlet combo with a service switch box. Remove the outlet and add a 2" extension box, Install a switch, cut the plug off the cord and wire into the box.
If you do have the switch, just delete the plug/outlet combo.
Whats your vent and tank plans/setup ?
If you do have the switch, just delete the plug/outlet combo.
Whats your vent and tank plans/setup ?
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kenfath
Well-known member
^^^^^ Agree! Looks good to me.
That's looking good !! You've got guru advice already on your electrical so you're all set there. Excellent work on the natural gas run and drip leg. 
Here's a quick video if you want to see vent pipe installation.
http://www.ronhazelton.com/projects/how_to_install_a_gas_heater_for_a_garage
Here's a quick video if you want to see vent pipe installation.
http://www.ronhazelton.com/projects/how_to_install_a_gas_heater_for_a_garage
Thanks for all the help. The vent goes up last since I am going to have a professional come out and cut a hole in my roof. I just can’t bring myself to do it. I am sure I could but just too apprehensive it might leak sometime in the future. I will also have him look over the rest of the install to make sure everything is okay and won’t burn down or blow-up my house later since it is attached.
The little box in back where the power supply connects is not a service switch; it is just an electrical box to make the electrical connection. I just started running the wiring and went with 12/2 since I had about 50’ on hand. As I started to connect it, I noticed a tag inside the heater that states it only draws 3 amps max (see about the middle of the attached picture). Since I only know enough about electricity to be dangerous, why does this need to be on a dedicated circuit? I believe my coffee maker draws up to 8 amps. Also, why would it need a service switch if it could just be unplugged?
Again, thanks to everyone for the help. I do not doubt what everyone stated, I am just trying to learn and reason this myself.
The little box in back where the power supply connects is not a service switch; it is just an electrical box to make the electrical connection. I just started running the wiring and went with 12/2 since I had about 50’ on hand. As I started to connect it, I noticed a tag inside the heater that states it only draws 3 amps max (see about the middle of the attached picture). Since I only know enough about electricity to be dangerous, why does this need to be on a dedicated circuit? I believe my coffee maker draws up to 8 amps. Also, why would it need a service switch if it could just be unplugged?
Again, thanks to everyone for the help. I do not doubt what everyone stated, I am just trying to learn and reason this myself.
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dipper
Well-known member
I think you are fine on a 15A circuit, as noted it only draws 3amps, so no real benefit to bump to the larger 12/2 cable. I think it's a cleaner install to have it on a separate circuit, makes it easy to troubleshoot if you have too. I put mine on a dedicated circuit but it is also shared with the OHD opener which i have yet to purchase and install.
I think either the cord plug or a switch at the unit is a good means of disconnect.
I think either the cord plug or a switch at the unit is a good means of disconnect.
Woodchopper46
New member
kenfath
Well-known member
'I think' the reason for having a dedicated circuit is the heater is considered a furnace; and furnaces are required to have a dedicated circuit.
The hard wiring vs. a plug seems to be a regional thing. When I was in the midwest and east, only found hard wired installations with a nearby switch. In S. California and Arizona I've only found plug ins. I've had both installations and finally decided I have no preference. Both work equally and serve the same purpose.
The hard wiring vs. a plug seems to be a regional thing. When I was in the midwest and east, only found hard wired installations with a nearby switch. In S. California and Arizona I've only found plug ins. I've had both installations and finally decided I have no preference. Both work equally and serve the same purpose.