Air Compressor Question

[Bob Vavricka]

I am looking at a used air compressor that has a Quincy 310 compressor on it. and have 3 questions (for starters)
What would you check to see if it is in decent condition?
I looked at the specs on this compressor and it lists a L.P. Bore (3.50) and a N.P. Bore (2.00)--can someone tell me what the L.P. and N.P. stand for?
It has a 5hp 3 phase motor and I would replace it with a 5hp 1 phase motor--are there any pitfalls I need to be aware of in doing this?
Thanks,
Bob V.

[mickey cassiba]

Without looking it up, it sounds like you have a two stage compressor on your hands, the big bore is the initial compression,and on it's exhaust stroke the air usually runs through a cooling coil and into the smaller bore to be re-compressed, thence through another cooler and into the vessel. Quincy has a decent website, we have two of their units here at work, a rotary and a two stage recip(piston) model. Both are pretty tough.Yours should do fine on a 1 phase motor, just don't try to scrimp on the HP.
Mick

[Jerry Solomon]

I think it may be L.P. Bore (low pressure) and H.P. Bore (high pressure). Nameplate data gets a little hard to read after a while.

[Jeremy Brant]

Couple things to check would be to pull the air filter and check its condition. If it's really dirty that would give you a quick indication of the maintenance level the compressor received. If it has an oil sightglass, check the level and color of the oil. If it doesn't have a sightglass, see if you can get permission to drain a quick sample into a plastic cup. If you don't know already, ask what it was being used for. Compressors used in an industrial environment, or used for a lot of high consumption tools (ie blast cabinets) will have much more wear and tear. It doesn't mean that they won't serve your needs, but the risk is higher for necessary repairs. Quincy makes excellent compressors, but it has to be priced right to make it worth changing out a 5 hp motor as they are not inexpensive. I wasn't finding any worthy of buying used on CL locally, and recently purchased an Eaton 5hp 2 stage upright. More than I wanted to spend, but they have a good reputation and it will likely meet my needs forever with normal maintenance.

[Howard Miller]

I purchased a Rolair 5520K17, http://www.rolair.net/ last weekend from local pawn shop. Great unit with plenty of cfm from only 1.5hp. If I wanted more air, I could replace the motor with more HP. The pump on these are very robust. One of my better purchases. These sell new for ~600.00. Sprays HVLP without any issues.

[Gregg Feldstone]

Howard, do you think I can get a compressor with similar specs. that is any better than the Rolair 5520K17 in the $600-$700 price range? Who has good prices on these?

What do you think of the 6820K17? It's only a little more expensive and gives you 8.4 CFM compared to 6.9 CFM from the 5520K17.