# What connector for 6x4 tube to new switch?



## Macabelli (11 mo ago)

I've got Clarke Range Air 30 compressor. I've replaced the switch but I'm left with a small tube going from the intake fan with a fitting that doesn't match the new switch. the original had a spring mechanism needle(I'm guessing one way mechanism). What's the name of the fitting/part that will allow to connect the new switch and the tube?


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## stevon (Mar 5, 2019)

Macabelli,

the little pipe is the head and fill tube unloader. The pressure switch has a release valve that unloads the air in the cylinder output and the check valve. This valve stays open after a charge cycle so that there is no air pressure in fill tube when it starts up again (less resistance).The relief or unloader valve is closed after a second when pump and motor is already turning (compressing air) I recommend that you replace the check valve as they clog, corrode or just wear out. It's a maintenance part like the air filter.

Stephen



Macabelli said:


> I've got Clarke Range Air 30 compressor. I've replaced the switch but I'm left with a small tube going from the intake fan with a fitting that doesn't match the new switch. the original had a spring mechanism needle(I'm guessing one way mechanism). What's the name of the fitting/part that will allow to connect the new switch and the tube?
> View attachment 11116
> View attachment 11117





Macabelli said:


> I've got Clarke Range Air 30 compressor. I've replaced the switch but I'm left with a small tube going from the intake fan with a fitting that doesn't match the new switch. the original had a spring mechanism needle(I'm guessing one way mechanism). What's the name of the fitting/part that will allow to connect the new switch and the tube?
> View attachment 11116
> View attachment 11117





Macabelli said:


> I've got Clarke Range Air 30 compressor. I've replaced the switch but I'm left with a small tube going from the intake fan with a fitting that doesn't match the new switch. the original had a spring mechanism needle(I'm guessing one way mechanism). What's the name of the fitting/part that will allow to connect the new switch and the tube?
> View attachment 11116
> View attachment 11117


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## stevon (Mar 5, 2019)

Macabelli,

Yea that's the weird thing about the copper metal. Most metals get softer heating them up or stressing them, copper does the opposite, it gets harder and more brittle, less flexible. All you need is a fitting that has the correct pipe thread and a compression fitting on the other end to fit your pipe. A hardware store should be able to hep you if you know the sizes needed.

Stephen



Macabelli said:


> I've got Clarke Range Air 30 compressor. I've replaced the switch but I'm left with a small tube going from the intake fan with a fitting that doesn't match the new switch. the original had a spring mechanism needle(I'm guessing one way mechanism). What's the name of the fitting/part that will allow to connect the new switch and the tube?
> View attachment 11116
> View attachment 11117


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## Airluke (Sep 25, 2021)

stevon said:


> Macabelli,
> 
> the little pipe is the head and fill tube unloader. The pressure switch has a release valve that unloads the air in the cylinder output and the check valve. This valve stays open after a charge cycle so that there is no air pressure in fill tube when it starts up again (less resistance).The relief or unloader valve is closed after a second when pump and motor is already turning (compressing air) I recommend that you replace the check valve as they clog, corrode or just wear out. It's a maintenance part like the air filter.
> 
> Stephen


My limited understanding is that altho the unloader valve is a type of relief valve, it’s not commonly referred to as a pressure relief valve, just an unloader valve. It’s a small valve because it’s just unloading the line between tank and cylinders, and the cylinders. Not to be confused with the pressure relief valve on the tank outlet. The tank inlet has a check valve which is also a pressure relief valve but is also a one way valve. On a gas motor Conrader piloted unloader valve, the check valve is built into the pilot valve body because both are in the tank inlet. My 1957 IR inlet check valve is still good, so I left it in when I put a piloted unloader on to replace the electric pressure control. I would not replace the tank inlet valve unless it went bad.


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## stevon (Mar 5, 2019)

Airluke, 

The unloader valve releases the pressure in between the Head output and the check valve. If you hear air leaking after the fill or compressing air cycle, the check valve is leaking. The check valve is only used for one purpose: to hold back the air pressure in the tank from coming back up the fill tube and up against the cylinders. Check valves don't last forever and if ignored will eventually fail. Quite a common occurrence and a good deal of the posts in this forum address just that issue, usually blaming the unloader valve. If you added another check valve inline to the original, then you bypassed the issue if there was a problem with _your_ check valve. The safety or "over pressure" valve is a safety device. That is only engaged if something goes wrong with the motor controls and the motor keeps pumping air into the tank beyond an acceptable/safe level of air pressure in the tank. 

Stephen 



Airluke said:


> My limited understanding is that altho the unloader valve is a type of relief valve, it’s not commonly referred to as a pressure relief valve, just an unloader valve. It’s a small valve because it’s just unloading the line between tank and cylinders, and the cylinders. Not to be confused with the pressure relief valve on the tank outlet. The tank inlet has a check valve which is also a pressure relief valve but is also a one way valve. On a gas motor Conrader piloted unloader valve, the check valve is built into the pilot valve body because both are in the tank inlet. My 1957 IR inlet check valve is still good, so I left it in when I put a piloted unloader on to replace the electric pressure control. I would not replace the tank inlet valve unless it went bad.


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## Airluke (Sep 25, 2021)

stevon said:


> Airluke,
> 
> The unloader valve releases the pressure in between the Head output and the check valve. If you hear air leaking after the fill or compressing air cycle, the check valve is leaking. The check valve is only used for one purpose: to hold back the air pressure in the tank from coming back up the fill tube and up against the cylinders. Check valves don't last forever and if ignored will eventually fail. Quite a common occurrence and a good deal of the posts in this forum address just that issue, usually blaming the unloader valve. If you added another check valve inline to the original, then you bypassed the issue if there was a problem with _your_ check valve. The safety or "over pressure" valve is a safety device. That is only engaged if something goes wrong with the motor controls and the motor keeps pumping air into the tank beyond an acceptable/safe level of air pressure in the tank.
> 
> Stephen


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## Airluke (Sep 25, 2021)

I didn’t have a bad check valve. I now have two good check valves, the original 1957 I.R. valve, and the one that came inside my Conrader valve. I kept the old IR one in because it was a nice adapter, it goes from 1” male on the tank to 3/4” female for the pilot valve which I wanted to be a male thread. Also because i liked the hex on the tank and the added height which made the pilot valve more accessible. 
I don’t agree that rhe sound of an air leak after the unloader closes necessarily indicates a leaking check valve. There are a number of other possibilities, one being a stuck pilot ( unloader) valve. Another being a gauge, or pressure relief valve. 
What you call the “ over pressure”. and “safety” valve is in fact the tank pressurerelief valve which is indeed a safety valve but which plumbers only call a pressure relief valve, like every hot water tank has. Those do cause explosions when they fail, sending the tank flying. As I said, That valve has to be good. It’s always on the outlet of the tank, on the first T. 
Yes I know and I said rhe unloader valve discharges air from the pump to tank line. That’s a strictly mechanical device to n my ild IR, uses centrifugal force to close and then opens when the pump stops rotating. That discharges the pump-to-tank line. The unloader in my Conrader valve discharges not just that line but the tank in order to close the check valve while the gas engine kicks down to idle. I say if the check valve ( which is a pressure relief valve named for its function, like the unloader valve) jams either closed or open it’s not a safety issue. That’s just my opinion and im open to correction. If the check valve fails closed, from corrosion, which is unlikely since they’re made of brass or stainless and get cleaned by the air which is why my 1957 check valve still works fine, you’d have a hard time starting a gas motor. And If you’ve got loose belts they’d slip. If you’ve got tight belts you might burn up an electric motor, since the pump could not turn against closed check valve. If you have a gas motor you’d probably stall the motor. I don’t see a safety issue but as I said, I’m interested in other opinions. I’ll do a search but I have a hard time believing bad check valves are as common as you claim on this forum. Would like to hear other opinions on the safety issue.


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## stevon (Mar 5, 2019)

Airluke, 

I see no reason to blast someone, or blast anyone on this forum. It is a public forum to trade information. 
Now the unloader valve does not even have to exist for a compressor to work. I had one compressor with no unloader valve at all and the compressor worked just fine. The pin hole was in the fill tube fitting and remained open all the time, just like any unloader valve at the end of a fill cycle. The minor air loss leaking while pumping into the tank was a choice of the engineer who designed the compressor. Compressor would run up to set value, power was shut off and pin hole hissed for a full minute after a fill cycle. This design worked fine until the check valve stopped working then the pin hole was constantly hissing until the tank pressure dropped and fill cycle was tripped on. I did not solder the hole closed to fix the problem. I knew that since the pump was not running the only possible source of the air leaking was from the filled tank. So taking out and examining the check valve found out that it was leaking, replaced it and the constant venting or hissing stopped, problem solved. This is a very common problem.

Stephen 



Airluke said:


> I didn’t have a bad check valve. I now have two good check valves, the original 1957 I.R. valve, and the one that came inside my Conrader valve. I kept the old IR one in because it was a nice adapter, it goes from 1” male on the tank to 3/4” female for the pilot valve which I wanted to be a male thread. Also because i liked the hex on the tank and the added height which made the pilot valve more accessible.
> I don’t agree that rhe sound of an air leak after the unloader closes necessarily indicates a leaking check valve. There are a number of other possibilities, one being a stuck pilot ( unloader) valve. Another being a gauge, or pressure relief valve.
> What you call the “ over pressure”. and “safety” valve is in fact the tank pressurerelief valve which is indeed a safety valve but which plumbers only call a pressure relief valve, like every hot water tank has. Those do cause explosions when they fail, sending the tank flying. As I said, That valve has to be good. It’s always on the outlet of the tank, on the first Yes I know and I said the unloader valve discharges air from the pump to tank line. That’s a strictly mechanical device to n my ild IR, uses centrifugal force to close and then opens when the pump stops rotating. That discharges the pump-to-tank line. The unloader in my Conrader valve discharges not just that line but the tank in order to close the check valve while the gas engine kicks down to idle. I say if the check valve ( which is a pressure relief valve named for its function, like the unloader valve) jams either closed or open it’s not a safety issue. That’s just my opinion and im open to correction. If the check valve fails closed, from corrosion, which is unlikely since they’re made of brass or stainless and get cleaned by the air which is why my 1957 check valve still works fine, you’d have a hard time starting a gas motor. And If you’ve got loose belts they’d slip. If you’ve got tight belts you might burn up an electric motor, since the pump could not turn against closed check valve. If you have a gas motor you’d probably stall the motor. I don’t see a safety issue but as I said, I’m interested in other opinions. I’ll do a search but I have a hard time believing bad check valves are as common as you claim on this forum. Would like to hear other opinions on the safety issue.


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## Airluke (Sep 25, 2021)

stevon said:


> Airluke,
> 
> I see no reason to blast someone, or blast anyone on this forum. It is a public forum to trade information.
> Now the unloader valve does not even have to exist for a compressor to work. I had one compressor with no unloader valve at all and the compressor worked just fine. The pin hole was in the fill tube fitting and remained open all the time, just like any unloader valve at the end of a fill cycle. The minor air loss leaking while pumping into the tank was a choice of the engineer who designed the compressor. Compressor would run up to set value, power was shut off and pin hole hissed for a full minute after a fill cycle. This design worked fine until the check valve stopped working then the pin hole was constantly hissing until the tank pressure dropped and fill cycle was tripped on. I did not solder the hole closed to fix the problem. I knew that since the pump was not running the only possible source of the air leaking was from the filled tank. So taking out and examining the check valve found out that it was leaking, replaced it and the constant venting or hissing stopped, problem solved. This is a very common problem.
> ...


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## Airluke (Sep 25, 2021)

Sorry if I offended anybody. That’s a good idea. I have a manual valve on the 5/16 unloader line going to my IR tank so in case the unloader valve fails I can still get it going. There’s the conrader unloader for cutting down the gas motor speed and then there’s the one for discharging the cylinders and pipe that facilitates restarting, which electric motorized machines do a lot of whereas the gas motors idle down and keep running, just so anybody reading this doesn’t get confused. 
I’m glad that check valve wasn’t a danger. I still think that as long as the pressure relief valve on the tank is opening at 200 psi or whatever there’s no check valve safety issue. But I could be wrong.


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## stevon (Mar 5, 2019)

Airluke, 

The check valve is a one way valve to load the tank with air and is used to keep back pressure from occurring. Human nature is to ignore what is working, I'm human too and often take parts like check valves, fan belts, air filters, etc for granted. But when a problem develops, at least I know how to troubleshoot and hopefully save some money with an easy fix. That's what most folks in this forum are looking for. That said in this "throw away" consumer world, not everybody has hands on experience machining, fabrication, welding, mechanical repairs under their belt to help fix something. If you can accurately describe a problem, the solution becomes easy in my experience, guess I'm from another era when a man was trained to fix things in High School as part of his and eventually her diploma. Schools aren't what they used to be!

Stephen



Airluke said:


> Sorry if I offended anybody. That’s a good idea. I have a manual valve on the 5/16 unloader line going to my IR tank so in case the unloader valve fails I can still get it going. There’s the conrader unloader for cutting down the gas motor speed and then there’s the one for discharging the cylinders and pipe that facilitates restarting, which electric motorized machines do a lot of whereas the gas motors idle down and keep running, just so anybody reading this doesn’t get confused.
> I’m glad that check valve wasn’t a danger. I still think that as long as the pressure relief valve on the tank is opening at 200 psi or whatever there’s no check valve safety issue. But I could be wrong.


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## Airluke (Sep 25, 2021)

That’s for sure. Education serves the masters but it doesn’t have to. Curriculum has changed to enforce conformity and subservience instead of self reliance and cooperation. Skills make us strong.


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