air conditioner - generator woes

[Bob Buchanan]

Elgin, I had asked earlier about the change in elevation between your home tests and final destination. When i was pulling a 5thW, I had a 3600 Generac installed in my pickup. Before leaving the dealer in Sacramento (about sea level) I ran a test using the AC, my computer, battery charger, plus brewed a cup of coffee -- and it worked fine. So I paid the final bill for the install.

My first weekend out I drove to Reno over the Sierras from Sacto -- close to 5000 ft.  The genset choked when I tried the slightest "extra" load other than the air. Then, as the day got older, and hotter, even the air by itself would not run continuously. Each time the compressor kicked in, the Genset kicked out.

The formulas for Altitude and Heat reductions in output are something like this (don't recall the exact numbers):

1 % for each 1000 feet above sea level.

3% for each 1000 feet above 3000 feet.

1.7% for each 10 degrees above 77 degrees (F).

Anyway, FWIW, that was the culprit in my case w/the Generac 3600. It was a great install of a good genset, but useless in high altitude on a hot day.

My other thought was wondering if you are near a "good" genset service center. Here in Sacramento, or anywhere in NCal, the place to go is Holly Generators on Sunrise off of highway 50. A service center like that can tell you exactly what is happening and what to do about it.

 

[ElginRinger]

Elgin, I had asked earlier about the change in elevation between your home tests and final destination. When i was pulling a 5thW, I had a 3600 Generac installed in my pickup. Before leaving the dealer in Sacramento (about sea level) I ran a test using the AC, my computer, battery charger, plus brewed a cup of coffee -- and it worked fine. So I paid the final bill for the install.

My first weekend out I drove to Reno over the Sierras from Sacto -- close to 5000 ft.  The genset choked when I tried the slightest "extra" load other than the air. Then, as the day got older, and hotter, even the air by itself would not run continuously. Each time the compressor kicked in, the Genset kicked out.

The formulas for Altitude and Heat reductions in output are something like this (don't recall the exact numbers):

1 % for each 1000 feet above sea level.

3% for each 1000 feet above 3000 feet.

1.7% for each 10 degrees above 77 degrees (F).

Anyway, FWIW, that was the culprit in my case w/the Generac 3600. It was a great install of a good genset, but useless in high altitude on a hot day.

My other thought was wondering if you are near a "good" genset service center. Here in Sacramento, or anywhere in NCal, the place to go is Holly Generators on Sunrise off of highway 50. A service center like that can tell you exactly what is happening and what to do about it.

I'm in Central Texas so the elevation doesn't change much unless I go West into the mountains, which I haven't.  As for the temperature, it was 91 yesterday when I tried it so yes, heat could have been a factor. It's really beginning to sound like I should have researched more before I bought the gen.  That way I could have factored in needing a bigger generator to handle the summer heat.  Since it's less than a year old I may get an amp meter and check what it's really putting out and if it's not 20amps I may use that as ammunition when I take it up with the mfgr.  As always, everyone's been very helpful and I appreciate it.

 

[Karl]

Elgin,
If you look back, I provided a link to B&S where you could download the wiring diagram. At that time I said it is breakered at 15A for each leg regardless of which outlet you're plugged into. If your genset was not capable of putting out more than 15A, you wouldn't be popping the breaker. Even though the 20A outlet says "20A", it is still breakered at 15A; the maximum you can draw from either leg, so measuring it won't do any good. They may be able to provide you with a 20A 2-pole breaker, but because it also protects the 15A duplex outlets, I don't think they will do that. Liability, safety, etc. About your only solutions are to either (1) wire the a/c as a 240V unit (if it can be done) and use the 20A outlet, or (2) get a different genset that has a true 20A or more available at the outlet(s) and is breakered for it. Sorry.

 

[ElginRinger]

Elgin,
If you look back, I provided a link to B&S where you could download the wiring diagram. At that time I said it is breakered at 15A for each leg regardless of which outlet you're plugged into. If your genset was not capable of putting out more than 15A, you wouldn't be popping the breaker. Even though the 20A outlet says "20A", it is still breakered at 15A; the maximum you can draw from either leg, so measuring it won't do any good. They may be able to provide you with a 20A 2-pole breaker, but because it also protects the 15A duplex outlets, I don't think they will do that. Liability, safety, etc. About your only solutions are to either (1) wire the a/c as a 240V unit (if it can be done) and use the 20A outlet, or (2) get a different genset that has a true 20A or more available at the outlet(s) and is breakered for it. Sorry.

Thanks Karl. I think I'm just going to swallow the pride and admit that I should have done more research before the purchase.  I have a ranch so at least it will come in handy there and I'm thinking in cooler weather the gen should run the a/c when it doesn't have cycle as much.  Thanks again for everyone's help.