Air Compressor question

Arnold · March 21, 2012, 11:58:51 AM

My buddy gives me this Craftsman A.Comp. It has a horizontal 25 gal. tank on wheels,2 hp,6.7 cfm@90psi 110v/15a
It runs fine,pressurizes,shuts off. When it TRIES to re-start..it trips the 20a breaker. It does this until the tank is almost at zero. The re-starts fine.
When I run it with the outlet line open...it builds up 70 psi in the tank..and keeps running..and the outlet..about 60psi..and keeps running.

Any gueses as to whether the problem is in the compressor itself..or the motor.

Sorry..for my ignorance on air compressors.

Thanks..
Arnold..

WZ JUNK · March 21, 2012, 12:07:58 PM

Quote from: "Arnold"My buddy gives me this Craftsman A.Comp. It has a horizontal 25 gal. tank on wheels,2 hp,6.7 cfm@90psi 110v/15a
It runs fine,pressurizes,shuts off. When it TRIES to re-start..it trips the 20a breaker. It does this until the tank is almost at zero. The re-starts fine.
When I run it with the outlet line open...it builds up 70 psi in the tank..and keeps running..and the outlet..about 60psi..and keeps running.

Any gueses as to whether the problem is in the compressor itself..or the motor.

Sorry..for my ignorance on air compressors.

Thanks..
Arnold..

I am not an electrician but I will make a wild guess. Check the starter capacitor on the electric motor.

John

Rrumbler · March 21, 2012, 12:37:28 PM

There is a check valve/unloader valve where the line from the compressor to the tank goes in to the tank. It stops air from going from the tank to the head, and relieves the line pressure so the pump can start against no pressure; if it doesn't "check", or unload, you get what you are describing. Sears Parts probably has one you can get for replacement.

wayne petty · March 21, 2012, 03:46:15 PM

rumbler is totally correct...

if you post a MODEL number from the unit...

or a model number from the PUMP ...

the sears parts direct site will have the break down diagram..

post the model number here.. i will try to get you the exact diagram and explain how it works...

phat46 · March 21, 2012, 04:42:07 PM

Easy way to check if it's the checkvalve is to tap on the line from the pump to the tank. That will usually "unstick" the checkvalve and allow it to pump. I had one that i did that to for a while before i could fix it.

Arnold · March 21, 2012, 08:37:46 PM

Thank You Very Much Guys!! ALWAYS Great help out here!

Wuz is probably right with the starter capacitor too..as is Rumbler with the check valve. I am not an electrician either..but this thing just draws way too much current way to fast. Phat 46 suggests a hammer. Right on! A Beer for us two on me! I will try tapping it with a hammer! Wayne..I did try and find info about this thing..I did not have any luck as I could not find ANY into on my model #..even at the Sears site..guess I will have to phone them. The model # is 919.721720. This is very,very clear on the plate. Unless this is one of those things where it has a Canadian model # I dunno.. and is not listed where I am looking. I am not that far from a very large Sears/Craftsman service centre..I will call them. Or look at a comparable model. Can't be that hard. 2 hp.horizontalwheeled tank..25 gallon tank..110v 15a..6.7 cfm 90psi. They probably only made a zillion of those haha.

Thanks again Guys!

Arnold..

wayne petty · March 21, 2012, 11:04:45 PM

a parts direct search for 919 got me almost 400 compressors... when i selected air compressor from one of the filter links..

http://www.searspartsdirect.com/partsdirect/part-model/919?searchedModel=919&postFilter=true&modelFilter=true&productCategoryId=Air-compressor-Parts&brandId=&brandFilter=false&categoryFilter=true

got pictures of the tags around the unit...

you can use photobucket..

and yes.. the caps could be very dead...

even the craftsman motor will have a part number..

unklian · March 22, 2012, 12:21:07 AM

There are two types of compressor switches,
sounds like you need the "Unloader" version.

It is intended to bleed off pressure upstream of a one way valve.

That way, the compressor can start more easily.
Without that, very difficult to start.

BFS57 · March 23, 2012, 06:13:39 AM

Hello;
The fact that you state that the compressor draws too much current is absolutely correct! Even the thing says 110 volts, that kind of a compressor needs a dedicated outlet of at least a full 20 amps. That compressor can not be operated with any kind of extension cord!!!
If the outlet you are using is in a house that is older that will not work!
That could be a very good compressor but you have to properly "feed" it in order to get the most out of it!

Bruce

jaybee · March 23, 2012, 11:35:15 PM

"The fact that you state that the compressor draws too much current is absolutely correct!"

Just try plugging one in when it's accidentally been left turned on. That'll get your attention in a hurry...

Arnold · March 24, 2012, 03:08:42 PM

Thanks very much for all your help guys! Wayne..I spoke to Sears..there are too many 919 series compressors..and too many differences between them to get any parts info. on this particular model. This particular model is not online. They said to call Sears Canada..not online. Sears Canada has a parts manual..not available online..snail mail..it is $13.95..on it's way. Once I get it..I will check out the availability of the valve..and go from there.

Thanks again!

Quote from: "wayne petty"a parts direct search for 919 got me almost 400 compressors... when i selected air compressor from one of the filter links..

http://www.searspartsdirect.com/partsdirect/part-model/919?searchedModel=919&postFilter=true&modelFilter=true&productCategoryId=Air-compressor-Parts&brandId=&brandFilter=false&categoryFilter=true

got pictures of the tags around the unit...

you can use photobucket..

and yes.. the caps could be very dead...

even the craftsman motor will have a part number..

wayne petty · March 24, 2012, 05:32:17 PM

what.. canadian stuff is different.. does it turn the other direction.. you are not on the other side of the equator.. so the coriolis effect should not be a problem..

the more i think about it.. the more i am thinking that your main into the air tank check valve is leaking.. not sealing when the air compressor shuts off..

i wonder if there was some condensation and it tweaked it one cold night..

work the main tube from the compressor head loose.. then snug it just slightly.. turn the compressor on to fill the tank.. unplug the compressor.. loosen the tube.. you should NOT have any air leak back from the tank through that check valve...

once you do that..

you will want to hook the main tube back up.. then check the bleed tube.. that probably goes to near the pressure switch.. depending.. you should not have air on that with the air in the tank and the compressor off..

that bleed tube should release any air captured between the compressor heads and the check valve.. so the compressor starts up without pressure .. lets the motor get spinning before it builds pressure..

it will hopefully be in the manual...

BFS57 · March 25, 2012, 06:57:10 AM

Hello;
You know, it used to be "easier" to make repairs and get parts. Lots of those little hole in the wall stores have disappeared forever. Thats not to say that compressor parts are pretty much "the same" from model to model and that if you install something from another co's unit that "gets the job done" I'm, sure nobody will say anything. Heck look at a hot rod! I'm thinking that some mis matched parts that don't even belong, that make the system work, is part of the challenge of building a hot rod!
Who knows you might end up with something much better than it was originally offered.

Bruce

Arnold · March 26, 2012, 03:16:50 PM

Wayne..I did look at the 919 series compressor lists. They went from (as far as I looked) from about 1.1 hp to about 5hp and from 11 gallons to 60 gallons. Without the correct model# or serial # I was lost. Even some that looked similar..I just did not know. Sears told me there were an awful lot of those 919 series compressors and some major differences..without knowing I just don't know enough about compressors..to as Bruce..BFS57 to "hot rod" one..or just order a part. Right now..it works..I can use it. .Sears does have a parts list and a manual on it's way for me.
In the mean time..I will try tapping it with a hammer...and then I will go on to what you suggested. THANK YOU!

Thanks again Guys!

Arnold...

phat46 · March 26, 2012, 05:15:45 PM

Quote from: "Arnold"Wayne..I did look at the 919 series compressor lists. They went from (as far as I looked) from about 1.1 hp to about 5hp and from 11 gallons to 60 gallons. Without the correct model# or serial # I was lost. Even some that looked similar..I just did not know. Sears told me there were an awful lot of those 919 series compressors and some major differences..without knowing I just don't know enough about compressors..to as Bruce..BFS57 to "hot rod" one..or just order a part. Right now..it works..I can use it. .Sears does have a parts list and a manual on it's way for me.
In the mean time..I will try tapping it with a hammer...and then I will go on to what you suggested. THANK YOU!

Thanks again Guys!

Arnold...

Actually I just used a screwdriver hadle, light taps on the copper line.