Electric and generator question

crsutton81 · Jan 19, 2022

Looks like we might have ice and snow on the way for several days with wind. I started getting the generators ready but it's going to leave me with my little one for the house. Question is, will a constant 5500 watt generator run my central air handler which has electric heat in the bottom. Posted below is a pic of the only tag I can find on it. Thankfully this is the only time it's been necessary to may have a need to heat off of a generator. And Yes everything is proper for generator hook up by a qualified electrician.

dr sportster · Jan 19, 2022

P=IxE 4.1 amps x 120 volts=492 watts You have 5500.

Jim.ME · Jan 19, 2022

What size breaker feeds it? That will be a clue. 5500 watt generator is about 22 amps of 240 volt power. What is the amperage draw for the electric heaters in the bottom? And how many are there? That part of the tag is not visible in your picture, and it is the most important info.

492 watts sure doesn't include electric heat, the unit's fan maybe.

This post was edited by Jim.ME on 01/19/2022 at 09:28 am.

JMOR · Jan 19, 2022

Motor + heater =21.4 amps& at 230 volts= 4922Watts
Question is, will your gen support that load, so close to its max rating for a long duration?

Steve@Advance · Jan 19, 2022

Generators are rated for max wattage, it won't consistently carry that load.

Rule of thumb, deduct 20% from the rated numbers.

You would really be pushing it. And that's just for the heat system!

If that's all you got, you could go in and unplug one of the heating elements. Won't make as much heat, but better than nothing.

used red MN · Jan 19, 2022

Sportster look at the the part of label in the top of the photo his light is not illuminating to well. It shows at least one series of heat strips at 17.5 amps. There may be more if we could see the rest of the label. Usually running a generator at max like that for a long period is not ideal.

miangus · Jan 19, 2022

The system may only use those heat strips (electric resistance heaters) when the outside temps reach a certain temperature (that temp depends on system design). So, while using the heap pump portion of the system (I am assuming it is a heat pump) the generator should handle the load. Running generators at full load consumes a lot of fuel. I used to run my 2500 watt Coleman powerbase to heat my tractor which had a 2000 watt tank heater, running that heater and a battery charger would fully load that poor generator. It would only run about 45 minutes, just enough. I know 5500 generators have a larger tank but I would doubt it would make 12 hours at full load.

JMOR · Jan 19, 2022

IF it is a heat pump, then need to know the compressor (outdoor unit) load/nameplate info.

Jim.ME · Jan 19, 2022

He said air handler, so I am assuming central air with heat strips, no heat pump and he indicated he expected the heat to run. An online chart for his unit shows the 240 heaters starting at 20 amps, 30 amp circuit required and going up from there, on 208 volts the heaters show as starting at 17.3 amps. without knowing which heater(s) it has in it, knowing what it has for a breaker in the panel will go a long way to giving the right answer here. JMHO

Destroked 450 · Jan 19, 2022

Look in your breaker panel to see what size breakers run you central unit

Mine has 4 heat strips and is feed by a 50 amp breaker
The compressor and air handler are feed by a 30 amp breaker

My short answer is no, that generator will not run your central unit
On our last outage my 5500 watt surge, 4500 watt continuous generator would not pull the water heater and water pump at the same time, we had a couple of small ceramic heaters for heat and they had to be turned off to run the water heater

Kansasredneck · Jan 19, 2022

Those small generators produce dirty power. I owned a number of duplexes back in 07. When we lost power I set up generators to power the gas furnaces. Ended up having to replace all the main control boards.
One solution is to create a battery backup system using the generator to power a battery charger and an inverter to feed sensitive equipment. With that you can also run with a smaller generator than you would otherwise need.
There used to be a number of videos on YouTube for outdoor and prepping sites.

OH Boy · Jan 19, 2022

That generator will not be big enough. Your air handler is likely equipped with a 15 or 20 kw heater package. Your generator is only 5.5 kw.

crsutton81 · Jan 19, 2022

Just got back to the house to look at breaker on heating system and there's 1 45 Amp breaker for the whole system. Here's another picture of the air handler label. If I had to, I could put one of the tractor pto units here but really needed them elsewhere. How many total amps is this unit really pulling so I'll know how to manage my generator load ? I haven't figured that part out yet.

Jim.ME · Jan 19, 2022

(quoted from post at 20:48:11 01/19/22) Just got back to the house to look at breaker on heating system and there's 1 45 Amp breaker for the whole system. Here's another picture of the air handler label. If I had to, I could put one of the tractor pto units here but really needed them elsewhere. How many total amps is this unit really pulling so I'll know how to manage my generator load ? I haven't figured that part out yet.

<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto114603.jpg>

That chart shows several different heaters could be used in your unit. Which one is in it? Going by the 45 amp breaker size it could be the second one down that shows that heater uses 32 amps. Plus the 4.1 amps for the motor that would be 36.1 amps at 240 volts or 8664 watts (with no extra margin) required. So, your 5500 watt generator will not do it. (The suggested breaker allows for 10800 watts.)

crsutton81 · Jan 19, 2022

Ok. Thank you Jim. As to which set
of heating elements are in the unit,
I don't know. Looks like I'll have
to swap out for one of the bigger
Gen sets for the house. I was trying
to retain those to the greenhouses
if at all possible.

MarkB_MI · Jan 20, 2022

My guess is your generator is not up to the task. It appears your heat strips were field installed, so there's no easy way to determine how much power they draw. But even if your 5500 watt generator can handle the heat strips alone, you're going to have other loads that will push it over the edge. Refrigerators require a lot of current to start and it's doubtful your generator can run the heat strips while starting your fridge.

The simplest way to find out is to hook up your generator and give it a spin. You'll know almost immediately if it's going to work.

dr sportster · Jan 20, 2022

I think I read your label wrong and perhaps you should ignore my math

Electric and generator question

crsutton81

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dr sportster

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Jim.ME

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JMOR

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Steve@Advance

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used red MN

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miangus

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JMOR

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Jim.ME

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Destroked 450

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crsutton81

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