CP model 40400 won't start?

by Don
(Spokane, WA)

CENTRAL PNEUMATIC AIR COMPRESSOR 2 HP-8 GALLON 40400


I need to know what to do when the compressor doesn't start?
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Hello Don. Nice to hear from you.

In a nutshell:

    -are you sure you are getting power?
    -if you have an on/off button, is it set to on?
    -do you have a re-set button on your motor? If so, push it.
    -is the pressure in the tank below the cut-in pressure of your pressure switch?


These are just a few of the things to check. You'll find more on this page.

Post an update for us as a comment here, if you would.

Cheers,

Bill

Comments for CP model 40400 won't start?

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Apr 30, 2015
Will not keep tank filled
by: Bill

Howdy Charlie. Try this. Empty the tank of air and start the compressor. Let it run up to cut out and shut down. When it does, monitor the unloader valve carefully. Did it operate?

Post a response with information if you would.

Bill

Apr 30, 2015
Will not keep tank filled
by: Charlie

My compressor started this problem about 2 years ago and I have just been living with it, but its driving me crazy now.

With the tank empty I can turn it on and it will pump fine. When the take pressure drops to where if should kick on the compressor gets power, starts to turn (I have watched the fan) and then the thermal trips. I have to let the air out completely for it to run again. It has the same results when it is cold out (close to freezing and below). I can't use my compressor all winter.

I figured it was the capacitor, so I ordered a new one. It arrived today and I just spent 30 minutes removing the old one and putting a new one on. No dice. I can turn the fan and motor by hand easily enough, and hear the piston pumping up and down. Any ideas?

Jan 07, 2014
Hard to start.
by: Anonymous

Model 40400 Central pneumatic.

I have to trip the on/off switch about 25-50 times to get the compressor to run. Is there anything I can do to improve this condition. Sometime it will trip the reset button. I am fed up with having to press the on/off switch so many times. Please Help....
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It sounds as though the ON/OFF switch is worn out.

Two things you can do. One is to replace the switch with a new one, the other is to remove the switch from the circuit entirely and rely on the pressure switch to turn the compressor on and off as the pressure cycles.

The downside of the latter is if you leave the compressor plugged in, and you have a leak in the system, the compressor will cycle on and off on its own.

I wasn't able to see an image of this model, so I don't know if the ON/OFF switch you refer to is part of the pressure switch. If it is, you will either replace the failed one with a new switch with and ON/OFF or replace it with a pressure switch that has no ON/OFF.

Bill

Apr 01, 2011
40400 won't start
by: tim

I have to release air to near zero pressure and then it turns over once or twice and trips the reset. Sometimes it catches hold and pumps up like normal. It is near new condition.

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That it's trying to start and cannot suggests to me that the unloader valve isn't dumping properly, and that, too, points back to the pressure switch.

Apr 09, 2010
won't start
by: Anonymous

i have power with and with out extension cord. On switch is on. Reset button won't start motor. I drained the tank from the screw below to make sure there is no humidity inside. Last use I had to drain the tank just to get it to start.
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In order for the compressor to start, electricity must flow through the pressure switch to the motor.

If all conditions are "calling for power", and the compressor motor doesn't start, and you have made all the checks to make sure there isn't another issue preventing the start, then I surmise that power isn't getting through the switch to the motor, and you need to look at the pressure switch at this point.

Bill

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Model 40400 8gal. compressor

by carlos
(lancaster, ca. (usa))

My only problem with this unit is that when it reaches the 100lb. mark it does not stop-it keeps going and about 115lbs. of pressure the pressure relieve valve opens up, and when it bleeds back down to about 98lbs. the pressure relieve valve closes and the unit starts again for another cycle. I have purchased a control switch, press-relieve valve and nothing worked. It still doing the same thing. I have run out of options. Does anyone have had this problem with these type of units.
any help will appreciated--thanks you....

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Bill says....

The device that shuts the air compressor off when it reaches the cut out pressure level is the pressure switch.

If you have replaced the switch with one that has a higher cut out level, and that level is higher than the PRV setting, then the PRV will let go before the compressor reaches cut out.

Check PRESSURE SWITCH page on this site for more details about yours.

Cheers,

Bill

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what kind of oil do i use for model number 40400

by Nick
(chicago)

needs oil what kind should i use

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Bill says...

You just pop over to the link OIL from the navigation bar, and have a read.

All info is there for you.

Cheers,

Bill

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CP Model 40400 will not shut off after reaching max working pressure

Unit will build pressure but will not shutoff after reaching max working pressure (115 psi)

the safety value appears to be operating.

I have replaced the pressure switch with new.

Any suggestions would be welcome.

Thanks
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If the pressure switch is still tripped to on after the compressor reaches the cut out pressure setting (power is passing through the switch to the motor) then it is the switch that is the likely culprit.

The pressure switch should trip to off (no power passing through it) when the compressor reaches cut out.

So, when your compressor gets to the cut out pressure, is the switch tripping off or staying on?

Bill


Tom

Comments for CP Model 40400 will not shut off after reaching max working pressure

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Mar 28, 2016
Capacitor
by: Anonymous

My compressor start but after a few seconds my capacitor start over heating and smoke start coming out of it

(PLEASE START A NEW THREAD - MODERATOR)

Sep 16, 2014
CP 40400 Cap.
by: Wilson

I have a CP 40400 air compressor that has a bad cap. i searched all over and after awhie I put the cap away and now I need the compressor. I know the cap was a CBB60 but unsure of the uF on that model and cant seem to find anyone who can tell me what it is. I think it was a 25 5uF 450V 40/50/60... but just dont know. No one here in New Orleans had the thing and I was told it is a start run cap. Do you happen to know what the details are on this cap so i can find a solution? Thanks.

Mar 18, 2014
40400 reset
by: doug

Hi All,
I heard a hum and a pop. Now the compressor will not start.
where is the reset? I have the instructions but the button for resetting is not clear. Does someone have a picture?
Thanks!
- Doug
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A hum and then a pop suggests to me that your start capacitor has pooched.

Is power getting past the pressure switch to the motor circuit? Is the tank empty of air (in not, empty it) and see it the compressor starts then.

What you call the reset is likely the thermal overload for the motor, and if the motor is not running, overheating shouldn't be an problem.

B.

Oct 21, 2013
CP Model 40400 will not shut off after reaching max working pressure
by: Anonymous

Bill:

Assuming that the cut out pressure is 115 psi (max working pressure) the switch is staying on above that psi.

At approx 120 psi I push the button to shut the motor off.

Thanks much.
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The Central Pneumatic 40400 air compressor has what I call a typical pressure switch.

If power to the motor circuit is still passing the pressure switch when the tank pressure passes the normal cut out setting then I believe you have a bad switch, the settings of the current switch are wrong, or it has been installed incorrectly.

Bill

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