My compressor suddenly developed a leak in the pressure switch. This is an "L" shaped switch easily visible on the compressor. However, when I went to Sears and showed them the part from my compressor and the part as it looked installed on the same compressor in the store they said they couldn't find the part. They recommended that I start ordering pieces paying for shipping and return shipping until I get the right piece. The part does not show up on their parts breakdown illustrations or lists so they don't know what to do. Can anyone help? Thanks!!
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Re: Leaking Pressure Switch
Leaks at the pressure switch are usually associated with the unloader valve due to leaking checkvalve at the tank. To determine the faulty part requires a couple of tests. Run compressor till it shuts off and is full of air then unplug the unit. Spray soapy water or (windex) around the base of the pressure switch to find where air is leaking from. There is a rubber diaphragm incorporated into the base of the pressure switch that may develop leaks. If the base is leaking check for loose parts or screws. If the air is leaking from a valve that looks like a tire stem, then leak is a result of faulty check valve in tank. Follow the 1/4 tubing that is connected to the pressure switch down to the brass valve at the tank. This brass valve is not holding tank pressure causing leak at the pressure switch. Replace as neccessary. The pressure switch is expensive. Do not replace unless you have looked at checkvalve. A universal pressue switch can be and should be used to same money. The check valve need not be replaced with exact replacement. Universal parts are available at www.grainger.com . Just match tubing and thread sizes and pressure range for the switch. Good Luck on your project and email if you have more questions. Please wait for the soapy water or windex to dry before you plug in the unit.
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Some pressure switches have a valve that reliefs the compressor head pressure when the motor stops and closes the head pressure relief valve when the motor runs.
There is a check valve that keeps air pressure from coming back to the compressor head and the relief valve.
I think the check valve is leaking tank pressure to the relief valve and compressor head.
The check valve is where the pressure switch mounts on to and it mounts threaded on to the compressor tank.
Try replacing the check valve
If air continues to leak from the pressure switch after cycle is indication that the check valve is not sealing or the pressure switch diaphragm has failed. Easy fix. Follow the 1/4 inch airline to the tank and remove the line from the brass valve(check valve). If air is leaking at the brass valve, remove it and attempt to clear debris under valve or replace as needed. If no air is leaking from the checkvalve, then most likely diaphragm is leaking. You could replace the diaprhagm or the whole switch. Generic switch is available thru ebay about 18- $20
Air leaking from the pressure switch indicates that the in-tank check valve is leaking. Follow the air discharge hose from the compressor to the tank. The brass valve at the tank is the check valve. With air in the tank remove the inlet hose from the checkvalve and spray soapy water on valve to check for leaks. If leaking, remove the valve and check for debris under seat or replace. If the check valve is not leaking then pressue switch is leaking from within switch(spray soapy water below switch) . Good luck
There is no unloader on a 2340N5 compressor. However there is a pressure switch that cuts the motor on an off. Located inside of the pressure switch is an air bleeder. When the pressure switch is opened the motor is shut off. A small lever in the pressure switch pushes down on the bleeder valve which lets the air on the compressor head to be released. This allows the the compressor to start up freely. There should be some air heard bleeding off at the pressure switch. If air continues to bleed off all the time the tank check valve is leaking.
If air is leaking back thru the compressor an air leak sound coming from around the air filter (intake) you have a valve leaking allowing trapped pressure to escape thru the air filter (Intake).
I would search the web for a flow chart. I have not seen one.
When the Pressure switch shuts off, the little air valve in the pressure switch vents the copper line from the compressor, to blead the pressure from the compressor so it's easier to start the next time. If it continues to leak, the check valve between compressor and tank must not be holding.
Before you adjust the perssure switch, make sure that the intank check valve is not leaking pressure back to the pressure switch after it cuts off at 140psi. The check valve should hold pressure at 140psi. Follow the discharge airline to the tank to find the checkvalve (either chrome or brass with large cap). To check for leaking valve, run compressor till shut-off at 140, then unplug the compressor from wall and remove the 1/4 air fitting at the checkvalve and check for leak. If leaking, replace valve and leave the pressure switch at present setting. You should be good to go. Good Luck with your repair and email if you have questions.
Usually, a leak at the pressure switch unloader valve is caused by the checkvalve in the tank. The unloader valve at the pressure switch bleeds out the air from discharge tube after compressor reaches set pressure. This only takes a few seconds. If air continues to leak then air is leaking back into the discharge tube past the tank checkvalve. Follow the air discharge line from the compressor to the brass valve at the tank. The brass valve is the checkvalve that holds the pressure in the tank. There are usually two connections at this valve. One is the unloader tube to the pressure switch. Simple test for leaking checkvalve, with pressure in tank unplug or switch off the compressor and remove the small unloader line at the checkvalve(brass valve) and look/listen for leak. If leaking, remove the checkvalve and examine seat/check for debris keeping the valve slightly open. If it cannot be cleaned, order generic replacement from www.grainger.com. It will cost less than the factory checkvalve. Just pay attention to the thread sizes for easy fit. Good Luck on your repair and email if you have questions.
I have worked on many makitacompressors and have run-across this problem on a few of them. Your compressor has a check valve that is supposed to hold tank pressure after the switch reaches set pressure. There is an unloader valve built into the pressure switch that releases the pressure in the discharge hose after the unit shuts off. The unloaderallows the compressor to restart with-out any pressure in the discharge line. If the brass check valve is leaking pressure back into the system, air will leak out of the unloader valve. Follow the discharge line to the tank and you will see the brass check valve. To test valve for fault, run the compressor till it builds around 80 psi and unplug the unit from the wall outlet. Remove the 1/4" hose connector from the check valve and check for air leaking out of the valve. If it is leaking you can order form www.toolpartsdirect.com. or call the makita 1-800 number. The price is about the same. Good Luck on your repair.