It has also come to my attention that some of our dealers don't know we do this. So I need to make two important announcements:
We sell rebuilt exchange Copeland 1hp compressor heads!
We buy your old Copeland 1hp heads!
When a Doctor calls and says "I DON'T HAVE ANY AIR" it’s a bad thing. The air compressor is the heart if the dental office without it, everything stops. The best thing is to be proactive and catch a problem before it becomes a crisis. You should make yourself a check list:
Check the oil level (if it has oil) it should be at least the middle of the sight glass and not over the top. Sometimes the sight glass is stained so always jiggle or shake the head to see the oil moving before you decide if it is OK or needs more oil. Most manufacturers recommend checking the oil every week I would say never less than every month.
Listen for knocking noises or leaking sounds,while the compressor is on and the office is working is the best but you may have to do this after hours. You want to pay attention to the run time because you want the compressor to be off longer than it is on while the office is working. If it runs all the time or cycles very quickly check the compressor system and the office for leaks. If a problem seems to exist and it is a twin or triple head run each head separately to see if only one head needs work.
Drain the tank if it has any water in it you should check the air-drier to make sure it is working properly.
If you find that a head only hums then clicks off, hum click, hum click, then you should check a few things. First (after making sure the power is off) check the oil again, without oil the crank shaft could have seized. The best way to check this is to drain the oil and see if it has any metal in it, (if it does that is probably ground up piston rod) If you still are not sure then take the rear cover off (that's the big round end with 14 half inch bolts) and see if the rotor turns freely. If all that seems OK then check the resistance of the winding by taking off the top electrical cover and check the resistance between R and S which should be between 5 and 8 ohms. If it is much over or under that the motor might be bad.
If you determine that a head should be good, then check the components in the start box which should have a potential relay, a start capacitor and a run capacitor the easy way to test these is by replacing them. Often you can find these locally from an appliance or refrigeration supply.
A few final notes, these things are heavy (85 -100Lb), and they are often dirty and oily, be prepared. If you need to replace one get the voltage from the name plate typically 115, 230, or 208-230 and make sure it is 1Hp.