803 vs central air unit...no go

76shovel

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Bunnell/FL
Well hurricane preparations are in order and have things to a point i feel ok with. So when i hooked the gen up to the house and gave a test run I wasnt really happy with the result. At first I had the a/c off and checked for everything and see where my load will be on the gauge. It was surprisingly low. So i turned everything off and attempted the a/c unit with zero success. The unit tries and can hear the contactors click. The compressor kicks but it dont have enough to power the fan motor. I can only check voltage with my meter at home and left my other meter at work so I cant measure amps or frequency. My lead is about 10ft long to a 60amp breaker then wired into the disconnect switch. The a/c unit is rated at 34 amp at starting load and 17 amps at running load....any thoughts to why the gen wont allow it to run
 

holley68

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My 002 runs my central ac. 2.5 ton I believe. It wouldn't run it until I put batteries in the thermostat. The power surge for the fan motor seemed to mess with the power to the thermostat. Batteries solved this and ac runs great!
 

Guyfang

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Well hurricane preparations are in order and have things to a point i feel ok with. So when i hooked the gen up to the house and gave a test run I wasnt really happy with the result. At first I had the a/c off and checked for everything and see where my load will be on the gauge. It was surprisingly low. So i turned everything off and attempted the a/c unit with zero success. The unit tries and can hear the contactors click. The compressor kicks but it dont have enough to power the fan motor. I can only check voltage with my meter at home and left my other meter at work so I cant measure amps or frequency. My lead is about 10ft long to a 60amp breaker then wired into the disconnect switch. The a/c unit is rated at 34 amp at starting load and 17 amps at running load....any thoughts to why the gen wont allow it to run
Have you load tested your gen set with something other then your house? It's best to know what your gen set can and will, and that's not always the same, pull for a load. There are a bucket full of reasons a gen set will not pull its rated load. Get or make a load bank, and get your base line first. Then and only then, can you determine what, where and if there is a problem.
 

Bmxenbrett

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NY
Not enough info in the first post. Whats the specs on your AC? Have you tested the starting amps with a meter? Older AC units can be harder to start.In the end if you cant get it working a window unit is very cheap and will save you fuel.
 

Bmxenbrett

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NY
Not enough info in the first post. Whats the specs on your AC? Have you tested the starting amps with a meter? Older AC units can be harder to start.

In the end if you cant get it working a window unit is very cheap and will save you fuel.
 

76shovel

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Location
Bunnell/FL
I did a generic load test. I used a electric stove amd was only able to to pull 60% and it ran fine. Smoked a small bit but didn't appear to be soot. This is the same gen that carries low oil pressure after being ran for about an hour. So I figured that it was connected. As for the age of the a/c unit it was installed on 2001. It starts and runs fine on utility power. The well pump, dryer, stove, water heater and all other electrical items function as they should with gen set running. I did some sime looking over everything and decided to opt for the window unit and grabbed one from the garage and tried it in conjunction with miltiple loads and everything seemed fine. So to sum things up. The gen set has output as needed, loaded up to 60% per gen set gauge, Hz and amps have not been confirmed from known good meter, hooked up to house and grounded, powers everything with various loads and seem to run and keep rpm stable during load changes. Only issue is it won't power a/c unit on without any other load. The tag on the a/c unit is partially unreadable. I can read the FRA and FLA of 34 and 17amp and rated volts are 208/220. I understand with certain testing not done to confirm is a risk but what do you do when a hurricane is coming your way.
 

csheath

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FL
Get yourself a clamp on amp meter to test with. You can get one with the hold function at Harbor Freight for about $15. The one I have reads about 4 amps low compared to a Fluke but it's close enough. Don't buy the cheapest one that doesn't have the hold function. You will need it to hold the highest reading to test the AC unit and see how much it takes to start it on utility power.

My 803 starts my old 3.5 ton unit and runs it fine. You can hear it grunt a bit when the unit starts but it hasn't failed to start and run it yet. My rule of thumb is I leave all my 120V breakers on and run any two of the 240 breakers. If I need to cook or heat water I turn off the AC.
 
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Bmxenbrett

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NY
Thats a really old AC unit and im sure its had the piss run out of it living in FL. The compressors on these can take more amps to start the older they get. Also could be a week capacitor. A hard start kit and replacing the capacitor would be something cheap to try after you get an amp meter on things.
 

Guyfang

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I did a generic load test. I used a electric stove amd was only able to to pull 60% and it ran fine. (So the only thing that you KNOW for sure, is that it will carry 60% load no problem. That's 6 KW. Its safe to say, that most homes without a big ol Air Con can be run with a 5KW gen set. simply hooking it up to the house, and turning on things isn't really a scientific was to check out what the gen set will carry for a load. Probably 99% of a house load is a steady draw load. Doesn't go up much, doesn't go down much. A constant load is easy to carry. You need to figure out what is the total load of your house. Then figure out what the start up draw of the air con is.) Smoked a small bit but didn't appear to be soot. This is the same gen that carries low oil pressure after being ran for about an hour. So I figured that it was connected. As for the age of the a/c unit it was installed on 2001. It starts and runs fine on utility power. (Why should it not it start up on Utility Power? The only limiting factor is what size is the circuit breaker that is in line between Utility Power and air con. Not the rest of the house. Have you looked to see what size it is?) The well pump, dryer, stove, water heater and all other electrical items function as they should with gen set running. I did some sime looking over everything and decided to opt for the window unit and grabbed one from the garage and tried it in conjunction with miltiple loads and everything seemed fine. (Maybe try turning every other thing off in the house, by opening the circuit breakers on everything BUT the air con, then reading the Amp draw for JUST the air con. Then you can see the max draw, and normal draw.) So to sum things up. The gen set has output as needed, loaded up to 60% per gen set gauge, (This gauge is about as trustworthy as a used car salesman. Get a GOOD meter. It will pay for itself.) Hz and amps have not been confirmed from known good meter, hooked up to house and grounded, powers everything with various loads and seem to run and keep rpm stable during load changes. Only issue is it won't power a/c unit on without any other load. (This leads one to think that A: the gen set has a problem, or, B: the air con needs a soft start upgrade. And 18 years old air con is not the most energy efficient thing in the world.) The tag on the a/c unit is partially unreadable. I can read the FRA and FLA of 34 and 17amp and rated volts are 208/220. I understand with certain testing not done to confirm is a risk but what do you do when a hurricane is coming your way.
You might try turning everything off, start the air con and then turn each circuit breaker back on until they are all on, or the main gen set circuit breaker pops.
 

gatorbob

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I have seen that some Heat Pumps have a larger LRA than a standard air conditioner. I had to use a soft start kit to make my 3.5 ton heat pump work. A hard start did not reduce the startup surge time enough. I used an EasyStart 386.
 

76shovel

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Bunnell/FL
Guyfang...i did try running only the a/c unit with no other load being applied to generator. That was what really had me stumped. I understand all my efforts are half assed and never intended to be in this situation. I work about 70+ hrs a week and working maintenance I was there more for the hurricane shutdown preparations not to mention getting my dads and uncles gen set tied into there homes as well because nobody wants to do anything until its last minute. I had recently gotten mine and have been working on it and reading the tm and msking sure i have all of them and the correct ones. In a perfect world everything is checked and is proper before being done. I am far from perfect and i know not everything was done before connectimg to my home. The last thing i want to do is cause more damage than the coming storm.


I guess i will read the tm's more and when i get back to work I will grab my other meter that i forgot there amd figure out what is wrong...thank you everyone for all you input and help
 

Daybreak

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Howdy,
I would say a good fully operational MEP-803A would start the unit. The biggest thing is to run the unit at a good 100% load (not the house) for at least 3-5 hours.

That will clean up the genhead, cylinders, valves, exhaust etc... You might be 2 hours into a run, and then notice little black particles are all over the top and on the ground too.

Stay safe down there.
 
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smokem joe

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Green OH
My 803a will start my AC unit with the well and some other 220 things going already. The hard start kit makes a big difference. You need to make sure your unit will put out at least 100% power and doesn't have any issues using some sort of disposable load bank.
 

69birdman

Active member
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Location
Summerfield, Fla.
Yeah find a better cheap used stove. Mine will bring my 803 right up to about 90%, add a fan and space heater ,takes it over 100.
My 803 will start my antique 3 ton ac no problem. It must have a hard start kit ,looking at the LRA of my ac.

P.s. Hope your fairing well as Dorian is upon you now. Nothing inland where I'm at, I've had stronger afternoon storms than this.

Peace
Brian
 

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rcamacho

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Bainbridge Island Wa
Yeah find a better cheap used stove. Mine will bring my 803 right up to about 90%, add a fan and space heater ,takes it over 100.
My 803 will start my antique 3 ton ac no problem. It must have a hard start kit ,looking at the LRA of my ac.

P.s. Hope your fairing well as Dorian is upon you now. Nothing inland where I'm at, I've had stronger afternoon storms than this.

Peace
Brian
Lol love the appliance load bank strategy


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