Air compressor

Jim2007,

You said "I found one that should work."

My recommendation is that if this is a stationary compressor and you'll be running a good length of hose to the tires to be inflated, than you want a compressor which will have a max pressure of 135+ with a cut-in pressure of 100psi or more. Many of the larger compressors have a cut-in pressure of about 90psi with a max of 120psi. The problem is when you're trying to inflate a tire to 90 psi over a length of hose, you'll lose pressure over the hose. So 90 psi at the compressor might correlate to 80 psi at the tire. The problem is the compressor won't "kick in" again until you drop to the 90psi at the compressor. If you have 82 psi in the tire, there's not enough pressure at the end of the hose to keep the air flowing and you're basically dead in the water until you manually release air in the line to get the compressor to kick in again.

I've got a 5 hp, 30 gallon 240VAC compressor in my garage, but the cut-in pressure is about 90psi and the max is 125 psi. Plenty of CFM capability. BUT, it's almost impossible (very slow & frustrating) to use it to put more than 80+ psi in a tire due to the pressure drop on the 75+ feet of hose needed to get to the motorhome.

I actually bought a smaller portable unit (oil-less) with 150 max, 135 cut-in, which works well to inflate my tires up to their max of 110 psi. It's CFM rating is much lower, but it has the pressure to push the air into the tires. I also use this oilless compressor to blow out the lines in the winter to eliminate water line contamination with compressor oil.

Now, if this is a portable compressor and your length of air hose will be minimal, then that won't be a concern.

As for 14 amps on a 15 amp circuit, it'll probably run fine most of the time. However, if it's really cold, you might have issues with the motor getting up to speed, especially if there is pressure in the tank. We had a compressor on such a circuit and in the winter time, we had to always start it with an empty tank for the first start of the day.

This might be more info than you need, but maybe it'll help someone. :)

~Rick

On Edit: If this is the one from Harbor Freight, then it has a cut-in pressure of 95 psi. It'll probably work OK for 80 psi. The manual online also gives maximum extension cord sizes & distances, as well, so if you're planning on wheeling it around to where it's needed that should give you some ideas as to what's doable.

It may be OK but you should consider installing a dedicated 20A plug and circuit. Using the 80% guide for sustained use would give you 16A and you can run the compressor all day long.

The typical 15A rated household plug is one of several on a 20A CB with 12ga wire. Make sure all other loads are off when using the compressor.

My house has 8 15A garage and outside plugs on a 15A CB with 14ga wire. When I ran my saw from the last one which as it turned out was 270' away it wouldn't cut hot butter. This circuit while very marginal meets all NEC codes.

I always use large draw equipment on a dedicated 20A plug.

If you worried about it, and ain't in a panic. get a smaller one,...don't need a 14 amp to get 90 lbs. I have a 1 gallon pancake in the MH that pumps 100 lbs, and runs on a 175 watt inverter.

The Central Pneumatic Air Compressor is rated at 14 amps but, as stated above, the start up draw will be much higher.
It's a fairly bulky compressor. We assume you do not plan on carrying it in your RV?

The rating for the compressor is the largest draw it will have when operating. The start up draw will be much more. A lot depends on the compressor as all are not the same. I have a Hitachi job site compressor that sometimes flips a 15 amp breaker. I never run it with an extension cord since air hose additions make up for extended runs.
Sometimes, if powered by a temperamental circuit, I'll empty the tanks so the compressor is not initially starting against full pressure. If I warm it up like that, it will operate on a 15 amp circuit.

I agree, it will work fine. You don't want to be running much else at the same time on the same circuit, of course. The compressor has a 15A plug on it and is designed to run on a 15A circuit.

That's a larger compressor than you need for topping off your tires, by the way, but if you think you might possibly use some other air tools that's probably not a bad thing. I carry a little Fini AirBoss compressor in my motorhome for tire duty and it dos a fine job for the 80 psi tires (and is also good for nail guns and similar sorts of air tools that don't need too much volume, but would not work out well for e.g. an impact wrench or die grinder or sander or paint sprayer).

No reason to overthink this, it will work fine.
I run a compressor with similar specs off 15A circuits in peoples homes and even on ext. cords all the time.

That's a big fella. If your breaker holds against the startup load, which could be 50-60amps, it'll likely run. Would a compressor be an intermittent load? I think NEC sets limits for amp draw on branch circuits, 85% iirc.