AR15.Com Archives
 Electricity needed for Oil Furnace
AoD  [Member]
12/28/2008 1:54:55 PM EST
About (roughly) how much electricity would I need to run my oil furnace if the electricity goes out?

It's a hot water (no fun for forced air) system...I'm guessing all I'd need is enough to spark it to start the oil burning, and to keep the fuel pump running....

Would this work?



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Waldo  [Moderator]
12/28/2008 3:36:25 PM EST

Look in the breaker box and see what size breaker it's wired to.

Then use this to figure the wattage.

BTW, that genset doesn't have a 220V outlet and won't work for you if your furnace runs off of 220.

MaineAR  [Member]
12/28/2008 3:42:22 PM EST
call an electrician and have a proper setup installed.
BBsound  [Member]
12/28/2008 3:45:35 PM EST
You will have a recirculating pump, or pumps, and maybe electric zone valves, the oil burner has a motor/blower, etc.

An electrician could tell you a lot pretty quickly.
Skibane  [Team Member]
12/28/2008 3:57:45 PM EST
Originally Posted By Waldo:

Look in the breaker box and see what size breaker it's wired to.

There may be other items wired to the same breaker (which would lead to an overly high estimation of the heating system's current draw). You could get a more accurate estimation by looking at the nameplates of each electrical device in the system, adding up the rated current consumption for each of them.
Ops  [Team Member]
12/28/2008 5:07:54 PM EST
Usual oil fired boiler will be running a 15 amp breaker, and actually pull about 8 amps. 8 x 120 = 960 watts. Have your furnace wired so you can plug it inot a dedicated outlet instead of hardwiring it. When the power goes out, unplug it from the house and plug it into the generator.

Ops (20 yrs Master HVAC)
Katahdin  [Member]
12/28/2008 5:42:39 PM EST
I have a AFG Beckett oil burner in my boiler, 700 watts max, 3 zones plus hot water. The fuel pump just spins off a rod that goes to the blower motor.

I've had to run it off a Briggs & Stratton 5.5/8.5KW Generator several times, when I do I don't even hear the alternator adjust to take the load.
HighCaliber  [Member]
12/28/2008 6:17:23 PM EST
The boiler should have a plate on it that lists the power requirements as should the circulating pumps. If that fails call the manufacturers, they will know. Most older homes have only a few fuses/breakers powering the entire house. I do not normally find a furnace or boiler that is on it's own independent fuse/breaker, at least in those older houses.
lumper  [Team Member]
12/28/2008 6:21:35 PM EST
You are going to have a water pump or pumps that will also draw current. The oil furnace heats the water. There is a separate pump or pumps that is usually close to the furnace, connected to the lines that run to your radiators or baseboard heat. You will need to measure the current draw of these motors while they are running also, and add that to your oil furnace motor to get your total energy requirement.
tommygun2000  [Member]
12/29/2008 2:11:24 PM EST
If that is all you want to run on it, a 1K generator will do it.

I just experienced this with a friend in the last Northeast ice storm, his furnace was forced hot water and my small Honda gen ran the thing no problem.

If you have any intentions of expanding your needs, go with a 5kw minimum.
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