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Discussion Starter #1
If I filled a compressor with air in the daytime.
Can it be left until the evening?
overnight?
How long before you are supposed to draiin it?
I know your not supposed to leave it pressurized.
 

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Insane Genius
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Sure you can leave it pressurised overnight, or even a day or two.

Leaving tanks pressurised is not recommended for a couple of reasons, firstly it reduces seal life and secondly its a safety hazard, So its best to make sure that you isolate and clearly identify it as pressurised.

I would make sure that you turn the compressor off though, few people realise how expensive compressed air is as a power source until they develop a leak and find that their compressor pump has been running for a few days trying to maintain tank pressure.

To give you a little perspective, In an industrial setting compressors are pressurised 24/7 and only get depressurised for maintenance
 

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You Rang?
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Just to add to what phenoix uk said. Its equally important to drain the tank perodically. there should be a drain valve on the bottom of the tank twist open the valve and let all the air out you may see some water along with the air. This is why your draining the tank to get the water out so it will not rust the inside..
 

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BAD INFLUENCE
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Not to argue any points , But I have a 80 gallon tank compressor, 220 volts ,and I have it filled all the time @ 120 psi. I do try to drain it at least once a month but not always do it. I have had this compressor for 20 years, and not a problem So I really don't know that there is a problem with storing air for any period of time.
 

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Insane Genius
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It is considered to be a safety hazard a pressurized 80 Gallon tank will contain a hell of a lot of invisible stored energy which could be the cause of an accident.
 

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If It is a real compressor and not some pos that has been piece mealed togethr it is not a problem. In the states all pressure vessels have to meet a standard that states the maximum pressure that it can contain. These standards are usually 125% over the operating pressure of the compressor output.
 

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Insane Genius
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If It is a real compressor and not some pos that has been piece mealed togethr it is not a problem. In the states all pressure vessels have to meet a standard that states the maximum pressure that it can contain. These standards are usually 125% over the operating pressure of the compressor output.
That is only the tank, you are not considering the risks posed by valves and fittings, you are not considering the historical data of accidents which involved people working on or near compressed air vessels without realising that they are pressurized, nor are you considering the risks to the emergency fire crews that may have to enter a building that contains a pressurised vessel.
 

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All the PROPER valves and fittings are and should be rated accordingly. I am talking about PROPER valves and fittings, not door closers, water valves ,etc. I do agree that there is a potential of something happening. But the odds of that happening are very slim. I personally have never heard of the scenerio you have stated, not that it couldn't happen....but the odds are very unrealistic. I work in an industrial enviornment and we run 3 150 hp compressors 24/7 without a problem.
 

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Insane Genius
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All the PROPER valves and fittings are and should be rated accordingly. I am talking about PROPER valves and fittings, not door closers, water valves ,etc. I do agree that there is a potential of something happening. But the odds of that happening are very slim. I personally have never heard of the scenerio you have stated, not that it couldn't happen....but the odds are very unrealistic. I work in an industrial enviornment and we run 3 150 hp compressors 24/7 without a problem.
Many accidents are the result of unrealistic odds.

All scenarios I have described are documented in numerous safety bulletins, and I've personally seen several examples, I guess the differences is that I work in dozens of factories that each use dozens of compressors and accumulators.

Anyway, I'm trying to explain the reasons behind the advice, if you don't approve of the advice and or reasons then thats your issue, it doesnt change the advice or reasons behind it.
 

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I would like to see the reports that you are referring to , it could help me to do a better job. I am by no way trying to discredit you or your points. I have worked with pressures up to 5,000PSI. I do realize that there is a possibility of something happening ,but again I am stressing that all the components that are in a compressed air system are designed for compressed air and not some home made cylinder ,valve,etc.
 

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the main problem with leaving the air compressed or night is that you probably with get condensation in the tank then when you use it it will push the water and or rust down the hose to your prop or tool causing rust and jamming of valves unless you have a filter downstream of the tank.
 

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I worked in an industrial situation (heating plant) for 23 years, where we used two 200 h.p. Quincy screw compressors constantly for coal and ash conveying. The pressure tanks had automatic blowdown valves which periodically exhausted air from the bottom of the tanks to eliminate moisture condensation.

In my own situation, I incorporated a solenoid valve which was connected to the drain fitting on the bottom of the compressor through tubing. The valve was wired so that whenever I turned off the compressor, it would completely exhaust the tank to prevent rust-through, since the compressor was in an unheated garage and went through servere temperature changes. I'd rather waste a little air than rust my tank out.

JMHO

Ron
 

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My father gave me his old compressor. Standard 5 gallon which will handle any air guns for construction. So its about 15 years old with about 12 years of day to day use. I have never heard of him removing the air, and I don't either. Havn't had any problems with seals.
 

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Never had a problem with any of my air tanks but i drain it down once and while one of the biggest problems is the rust in the tank from condensate so i keep an eye on what drains if it ever gets rusty its life will soon be over
 

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That is only the tank, you are not considering the risks posed by valves and fittings, you are not considering the historical data of accidents which involved people working on or near compressed air vessels without realising that they are pressurized, nor are you considering the risks to the emergency fire crews that may have to enter a building that contains a pressurised vessel.
Mine appears to have a safety feature for fire crews. The line from the compressor to the tanks is rubber, so it would rupture in a fire long before the tanks. That being said, the instructions say to depressurize it and store with the drain valve open, so that is what I do when I am done using it.
 

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Since were talking about compressors I have an old one that the neibor gave me when he moved I had to rewire the cord and replace the hose but heres my question what could be the cause of the compressor not shutting off and at what setting do they normally shut off?I tried to google info about compressors but I must be asking the wrong way becuase I can't find any info.
 

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Insane Genius
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Mine appears to have a safety feature for fire crews. The line from the compressor to the tanks is rubber, so it would rupture in a fire long before the tanks. That being said, the instructions say to depressurize it and store with the drain valve open, so that is what I do when I am done using it.

No that's not really there for the benefit of fire crews, its because the compressor vibrates and if they used a solid line then the fatigue from the vibrating compressor would quickly rupture a solid airline.
 

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Insane Genius
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Since were talking about compressors I have an old one that the neibor gave me when he moved I had to rewire the cord and replace the hose but heres my question what could be the cause of the compressor not shutting off and at what setting do they normally shut off?I tried to google info about compressors but I must be asking the wrong way becuase I can't find any info.
The compressor should have a pressure sensitive shut off switch which often has a screw adjustment which lets you set the on and off pressure levels.

You can normally identify the switch unit because it will be a unit that has both an air supply from the tank and an electrical supply, usually direct from the mains.

The switch has two settings the on level is the pressure at which the compressor turns on and the off level is the pressure at which it turns off, typically these could be set at 105 psi for the on level and 115 psi for the off level.

The settings for these levels really depends on the operating profile you want from the compressor, having a wide difference between on and off levels will cause the compressor to turn on less often, but when it does it will be for longer periods of time, and before it does you could have a large pressure drop (not a problem if you only use lower pressures) and a narrow band will mean the compressor turns on frequently for short bursts, and you will maintain a higher mean pressure.

If you are finding that during use the compressor is constantly on then its either too small for the job or you have a faulty switch.
 

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My 200 dollar 3.5hp compressor (cheapo oil lubricated) has had air in it pressurized since I got it in 1988. I drain the water in the thing maybe three or four times a year. If in a fire, the pressure relief valve would blow and keep the tank at a safe pressure. If the tank rusts it will get a spot (inside) in it and will release pressure slowly through that hole. If it leaks for any reason and the power is on it will run forever costing electricity and wear. Not sure what can happen in an industrial situation or what the safety bulletins look like but those are the guys that leave them pressurized all the time and just have a daily drain maintenance schedule. My two cents...
 
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