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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: goutoe on February 24, 2013, 02:58:21 PM



Title: Air relief
Post by: goutoe on February 24, 2013, 02:58:21 PM
I started my bus the other day 6v92 ta. I let it run about an hour I never did hear the air pop off? I crawled under the bus and drained the air tanks not much moisture there, I wonder why the system never bloused does it run on pressure, or something else? I noticed a wire to the blouse valve What activates this valve? Thanks for your input>>>>>>>>>>> John.


Title: Re: Re: Air relief
Post by: Seangie on February 24, 2013, 05:19:03 PM
John,

Did you check your air pressure gauge?  How high did the pressure build up to?  Mine kicks off at about a buck twenty or so.  If the pressure didnt build high enough then it might not kick off.  Quick guess would be a leak somewhere.

-Sean

 www.herdofturtles.org (http://www.herdofturtles.org)
1984 Eagle Model 10S


Title: Re: Air relief
Post by: wayne on February 24, 2013, 08:20:16 PM
I assume your are talking about the air dryer. I have an AD9 that pops when the air compressor kicks off cycle. There is a small 1/8" line that senses when the air comp cycles. The wire only controls the heater. I have always run these so I am not familiar with any other type.


Title: Re: Air relief
Post by: Scott & Heather on February 25, 2013, 05:24:07 AM
Another vote for an air leak. If you never quite get to 120 or whatever your purge psi is set at, it won't purge.


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Title: Re: Air relief
Post by: bevans6 on February 25, 2013, 05:47:25 AM
It's important to be very clear on what makes the air dryer purge.  The compressor runs, develops pressure.  The air compressor is controlled by the air governor.  When the air governor senses that a certain amount of air pressure has developed (usually around 120 PSI, it switches so the air compressor stops developing pressure and also sends a signal to the air dryer to tell it to purge.  When it purges, all the air stored in the air dryer and the line from the compressor to the air dryer is purged out blowing out any trapped moisture.  When the air governor senses that the air pressure has dropped to a set level (usually 95 psi or 25 psi lower than the high pressure cut-out point) the governor switches again, tells the compressor to start to develop pressure again, and tells the air dryer to close it's purge valve.

So if your air dryer did not purge, it's either because it's broken or because the air governor did not tell it to purge successfully.  Assuming the signal line between the governor and the air dryer is still intact if the governor did not tell it to purge, it's because the compressor did not develop sufficient air pressure, or because the governor is broken.  If the air compressor did not develop sufficient air pressure, its because the air compressor is broken or there is a leak.  Knowing that, you can now work backwards and see what the problem is - determine air pressure, determine fault, determine cause, rectify.  If only it were that easy in real life...   :o

Brian


Title: Re: Air relief
Post by: goutoe on February 25, 2013, 12:05:15 PM
Thanks guys, I may have found the problem, a very corroded butt conector on the wire close to the air dryer. I am going to replace that and see what happens, my air pressure was 120 on both guages, I didnt hear any leaks after I shut it down. Thanks again>>>> John.


Title: Re: Air relief
Post by: Len Silva on February 25, 2013, 12:10:03 PM
The wire is for the heater and has nothing to do with whether it purges or not, unless it is below freezing and the purge valve is frozen up.


Title: Re: Air relief
Post by: bevans6 on February 25, 2013, 12:59:50 PM
profile says kearney NB, and it's indeed below freezing there.  The heater may well be the ticket.  Good luck.

Brian


Title: Re: Air relief
Post by: buswarrior on February 25, 2013, 04:04:53 PM
My money is on the heater.

happy coaching!
buswarrior


Title: Re: Air relief
Post by: belfert on February 25, 2013, 05:15:55 PM
I had issues with my purge valve heater and it froze up big time.  I had replaced the purge valve with a 24 volt assembly and it turns out it was supposed to be 12 volt.  I had made an assumption since most of the coach is 24 volt that the purge valve heater would also be 24 volt.  It pays to check the voltage on the wiring diagram.