I see some small portable generators (3000 - 4000 watt) on sale. $450 (CAD, which is $340 USD) for a Champion generator - I think this one:
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My furnace has a conventional AC blower motor - not sure if it's PSC or some other type. It's either 1/3 or 1/2 hp and doesn't have a large capacitor either built into it or wired up near by. My 40-year-old furnace otherwise has NO electronics other than the gas-valve soleniod. No draft inducers, sensors, vent fans, etc.
Anyone ever run such a motor from one of these small generators?
Just thinking of picking up a generator to run my furnace (intermittently) in case of any extended winter power outage.
I would seriously suggest that you go to a slightly bigger & better make & model - this one doesn't have any 230 volt output. Also consider that your furnace is probably hard-wired - best to be prepared for the generator hook-up in advance - not after the power outage when it's dark & cold & the basement is flooding or freezer is thawing .. My Honda EM5000 makes a small dip when the furnace blower starts. A more noticable dip when the 230 volt well pump starts. Keep fresh stabilized gas on hand and test-run the generator every 3 or 4 months. Many people shut off the gas valve and run-it-dry after use or test. John T.
If the motor uses less than the 3550 watts for running, then there isn't a problem, but ensure the motor doesn't require more than the rated 4550 watts for startup or you'll continuously blow the internal fuse. Though, my question is...where do you plan to keep the generator? It needs to be vented if kept inside or people in the household will die from CO poisoning. Even if vented, I wouldn't trust using one indoors. Generators should always be used outdoors.
I've run several furnaces over the years, including modern ones with electronics, with no problems. No problems with anything else, eg TVs, water heaters with electronics, etc. Only failure with a generator that I've seen is a neighbor had a small one, maybe 2000W, and his electronic coffee maker failed while using it.
If it's a conventional generator, about the only bad thing I can see happening is if the voltage regulator failed and it went way over voltage. Operating normally, you'd think it would have to be pretty much a reasonable sine wave, just by virtue of how it's physically built. STuff without electronics doesn't have anything sensitive. And stuff with electronics typically has a switching power supply that will accept a wide range of input variation.
Still, having said that, with one of those expensive ECM motors on a new furnace, I guess I would still be a bit nervous. And maybe I'd use the older 43" TV, instead of the new 65", if you know what I mean.
While I have no personal experience, I spoke with one of the long-term, highly regarded, drinks #6 oil for breakfast, HVAC folk near our old home and asked him about backup generators.
He said they had been running into problems with the various flame/safety sensors, or possibly the ignitors, or both (?) which monitored teensey, tiny, current levels, and that these often shut down the furnaces and boilers 'cuz they'd get wrong readings.
He added that it was super critical to get good and solid grounding for everything involved.
Again, no personal experience, but it kind of makes sense.
I'm only considering this because (a) it's relatively cheap today and (b) if I ever did need it, then so would several thousand other people and there'd be none on the shelf in that case.
Absolutely no need for 220v.
Only considering it if I'd be in the middle of a multi-day (or longer) power failure in winter, otherwise this thing would be sitting in the box, possibly for the next 5 to 10 years or who knows how long. So it's a pretty end-of-the-world type situation that I'd put it to use. Truth is I'd probably end up loaning it to friends/family going camping before I'd put it to this anticipated emergency use.
I could easily rig up some wire to run the motor through the basement wall up to the outside where I'd have this thing running. Only the furnace would be on that circuit, disconnected from house wiring. Wouldn't need to power the fridge in this circumstance (the back porch would be our fridge).
My gas water heater uses no electrical power at all, not for burner and has no draft fan.
The only other thing I'd power off the generator would be my internet / network UPS.
So I guess the short answer is yes, they have or could power an ordinary fractional HP electric motor.
In many cases, it's not hard to do it right with an inlet and lockout kit for the main panel. That way you can power whatever you want in the whole house. Only issue is if there is a lockout kit available for the panel and an empty breaker spot. If not, in an emergency, I know what I would do.... Actually the powering anything in the house only applies if you have a 240V generator. With 120V, you could power about half the things, just on one leg. Which is why I'd agree with the recommendation to go with a 240V one. Especially if it's more than a day, the above allows you to turn lights on and off anywhere, normally, instead of wandering around with a flashlight in the dark.
Very interesting. On some of these they use a flame sensor that relies on just a steel rod, whereby somehow the flame itself generates a small voltage. Seems that would rely on sensing a voltage between that rod and ground, ie EGC. And if the generator is not properly grounded to the house ground, to the furnace, I can see how that would be a problem. And don't ask me about the physics whereby that flame sensor works....
You may want to look into the dual fuel generators that run on gas or propane. The propane stores for years. I found one like this on sale for about $ 350 and free shipping. It will put out 120 or 240 volts. If you only need 120 volts,you can flip a switch and parallel the 120 volt windings for twice the current. It even has a battery to start it. You just need to charge the battey every so often if you do not use it. It will start with the rope too if the battery is dead.
Just beware many of the camper generators only put out 120 volts and if you ever need 240 volts you will not be able to get it.
This unit comes with everything you need but the propane tank. The small BBQ grill size usually xost bout 30 to 40 dollars for an empty tank and less than$ 15 to fill them.
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They do have bigger ones.
We sledom loose power and I have a 5500 watt gas unit. I bought the propane unit so I do not have to worry about the gas for short durations of outage.
That should be plenty to run a furnace blower and a fridge along with some general lighting load. One trick, not exactly 100% legal is to replace the usual 2x4 handy box with the blower disconnect with a 4x4 box. Put an "inlet" in the second bay and change the switch to a "3 way". That is essentially a poor man's transfer switch.
Then you plug in your extension cord female end into the inlet, plug the male into your generator and flip the switch. That is all pretty legal as long as the switch is motor rated.
Another way is to install a short power cord to the motor/controller and replace the switch with a receptacle connected to house power. You would unplug that and plug it into your generator powered extension cord ... not so legal but not totally unsafe. Both are better than back feeding an outlet.
If they are using the MBJ in the panel as a current path to the thermocouple I can see that but it is not as much the "ground" (the grounding electrode system) as the grounding conductor to the furnace frame. OTOH the control circuit may just be using the furnace frame as the current path in which case we are really talking about the bonding of the thermocouple base.
What I had in mind was an interruption in the EGC between the furnace burner and the portable generator. You wouldn't think that would be easy to do, ie if you're using a standard extension cord it should be hard to impossible. But that might account for the problem.
But then on second thought, probably not even that. The sensing circuit for the flame rod would be between the flame rod and the ground of the circuit board, which is tied to the furnace frame. So, I take it back, if some people are having issues like described, IDK what the mechanism could be. Like I said, I ran several furnaces on a generator that were high eff, modern ones, they worked with no problems.
I don't always trust HVAC techs on electrical issues. They are more like plumbers. If there was an issue I might consider the fact that
*some* small inverter generators do not have main bonding jumpers. (like a 2000 Honda). I am still not sure why that would affect the thermocouple but how knows? It may have more to do with the thermostat not getting voltage (24vac) to start the blower and the furnace sees that. This is the wild card in all of this. The last time I had a furnace, the 24v transformer was on the blower circuit after the disconnect at the furnace (actually in the same box on the side of the plenum). That was a circa 1971 house in Md. Gas appliances with no electronics. The gas valves were fed directly from the thermocouple through a point on the blower relay in the furnace and the thermostat in the water heater as I recall. It was 35 years ago tho. There was no electrical connection at all to the water heater. It just had a pilot light.
So, having read your first post, you really want it to power the whole furnace, not just the fan.
Don't these things have actual AC generators? Not like UPSes that try to generate a sin-wave from a battery, or auto DC converters that try to generate a sin wave from the car's 15 volt output.
If they make actual AC, than all that matters is the wattage or amperage rating.
I agree with you. Unless you want to dry your laundry.
There will always be a few people here who will always to upsell posters, you should add this or that.
Right. When I buy tools I'll probably never need, I buy cheap ones. I don't know where you are but I believe you that you'll probably never need this.
That's good. I'm going camping next month. Will you have it by then?
If you get a camouflage generator, like this one is, you have to be careful that you don't lose it. Always keep the extension cord plugged in.
Some of them are incredibly quiet, although by suggesting this, I too am trying to upsell you.
(I looked at the picture and im sure that's too big to be as quiet as the little ones I was talking about.)
I'm too lazy to use the outside, but I've found the food stays cold, even frozen, for 3 days, even if I open the fridge a few times.
And the house too stays warm enough in 30 degree weather outside for 3 days. During which time you can work on the wiring. Make ssure you have the wire itself in advance. I guess heavy duty extension cords, and after that, some way to conect to the furnace, while disconnecting it from the house.
They don't use much. But they're probably not near the furnace, so more extension cords and a so-called cube-tap.
My whole oil furnace, including air circulation fan, igniter transformer and fan and oil pump, and tiny bit of circuity uses a 15-amp breaker, so I'm sure your fan doesn't use more than 15 amps, 1700 watts or so.
Go to bed at sundown, get up at dawn and use flashlights for the rest of the time. Wear muckalucks.
It's not really much of an "up-sell" to buy a lockout kit for the main panel and install an inlet instead of rewiring the furnace. And that plus a 240V generator will let you very conveniently power whatever in the house you choose to power, within the rating of generator. You manage the loads from the panel. Seems much more preferable to me than rewiring the furnace, then having an extension cord for it, plus extension cords and power strips for any other loads you want. And then the bathroom light switch still doesn't work.
Well, we know that would be bad, very bad. I've never seen any study of what the power actually looks like and what all problems people encounter. The only direct experience I've seen is a neighbor having the electronic coffee maker go kaput when using it plugged in to his very small generator. And I've read of a lot of people having troubles with using generators that have GFCI on the main 240V output, because the generator has the neutral bonded to the frame and the house does too. That causes the generator GFCI to immediately trip.
Now you have. This is the wave form of a cheap 5.5kw Briggs generator with about 98% load on it.
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This shoots the hell out of the theory that you need to derate the generator because you are running on propane ... at least the 5.5 Briggs anyway. Maybe they just oversized the engine tho.
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