A little help troubleshooting my Bauer

[underboats]

OK Pescador and other compressor guru's, I have an older bauer K14 (85'), 9.2cfm compressor that when starting there is no pressure on the fouth stage, thus it slaps every time. There is a check valve between the final separator and the purifer that was bad and I figured that's what it was so I replaced it. The check valve now holds but the fourth stage still slaps when the compressor comes on. What else is there that holds pressure on the fourth stage piston to keep it from slapping? There is a fitting between the fourth stage and the final separator but it does not appear to be a check valve. Thanks for everybodies help!

Chuck

 

[pescador775]

Hey, underboats, da guru to the rescue. How's it going, man? Well, piston slap on startup is normal. The floating piston in the final stage can't setup normal rhythm until it sees some head pressure (back pressure). Your Kidde did not slap because of the restricted channel at the discharge side. The drilled passage is so small that back pressure builds immediately.

 

[dannobee]

OK Pescador and other compressor guru's, I have an older bauer K14 (85'), 9.2cfm compressor that when starting there is no pressure on the fouth stage, thus it slaps every time. There is a check valve between the final separator and the purifer that was bad and I figured that's what it was so I replaced it. The check valve now holds but the fourth stage still slaps when the compressor comes on. What else is there that holds pressure on the fourth stage piston to keep it from slapping? There is a fitting between the fourth stage and the final separator but it does not appear to be a check valve. Thanks for everybodies help!

Chuck

That's normal, nothing to worry about. It goes away after 5-10 seconds, right?

 

[pescador775]

Underboats, the exhaust passage in the Kidde is the size of a #68 drill which is 0.031. Anyway, the big Bauer would need a restrictor about 2.5- 3 times the cross sectional area of a #68. A quick calc shows a .053 drill as 3 times, about the right size for a restrictor. Better check that yourself for accuracy. Well, maybe three times is a little over the top. Try 2.5 first time. That would be 0.049. Install in the tubing a little ways down from the final stage. Disclaimer, I have no clue if it will work.

 

[underboats]

Love that answer Pescador, I had total faith in you until your disclaimer. I think I'll put a T in the line so I can just use my lips to blow back into the compressor until it builds up some head pressure. How did you like my compressor upgrade? I went from a 2cfm Kidde to a 9.2 bauer with 4 storage bottles and a filling station complete with blast protection. A local company that services the fire departments took this one on trade from a small department. Only had 400 hours. It has a 7hp motor and dim's the lights in my house when it first starts. As for the piston I guess it is normal, I just didn't remember it slapping after the inital start for the first time. As always thanks for everybodies help.

 

[pescador775]

Sweeet!

 

[oxyhacker]

Do you mean it's clattering on startup, and you just don't like it, or that it is clattering all the time, or for an extended period (more than 15 seconds, say) after startup? If the former, it's normal and you should get used to it and not start second guessing Bauer in trying to come up with a way to "fix" it that could cause more harm than good. If the latter, it is probably a valve problem, and you should fix it since otherwise it will eventually damage the piston and will also be effecting output.

BTW if it doesn't clatter for a while, it means your were starting it under load, which isn't really good either, and can really dim your lights!

 

[underboats]

Thanks Oxy. I just clatters for a few seconds when starting. I realized what the difference is between this unit and my other Bauer is my other Bauer has manual drains so it still had some head pressure most of the time when it was started, this unit with automatic drains dumps the head when it shuts down. It is much better now that I replaced the check valve before the purifier as it does not have much volume to fill before the fourth stage has some pressure. Bad thing is there is no dive shop for 60 miles so everybody is finding out about my filling station. I went ahead and had the air testing done to fill tanks so now I have lots of friends. Next on the list is a hydro unit. Thanks eveybody!

 

[Chariff]

The prescribed treatment for the start-up clatter (which is absolutely normal...10-15 seconds) is a "Priority Valve", aka Back Pressure Valve or Pressure Maintaining Valve. It'll help to build head pressure on the floating piston but will not eliminate is altogether....it's simply inate to the design of Bauer's floating piston. This valve should be placed at the discharge to the filter system as it also helps to enhance the performance of the filter cartridge.