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JMP Accumulator - tips?

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Old 06-24-2012, 06:16 AM
  #1
ddennison
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Default JMP Accumulator - tips?

Finished installing my JMP accumulator for the 200SX in the UB after leaking UAT (air and fuel leak not responsive ot PTFE wrapping etc..)

Was wonderinf if those WHO USE THIS have tips for getting this thing running perfectly? Tom told me to place the "in" from the tanks at the highest point and I have done this -it is mounted 45degrees which he states is fine.

I was going to do my usual fill, maybe "drain" a few second off the fill line and then cap. Then start and observe

Should be that simple right? I have never had one where I couldnt see inside. The rest of my install to the tanks is solid, safety wired and not leaking with pressure tests.

Thanks for any thoughts,

Dave
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Old 06-24-2012, 11:21 AM
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David Searles
 
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Default RE: JMP Accumulator - tips?

Dave,

That little part about draining "a few seconds off the fill line" is the key! The Accumulator needs to be purged of all air and that is exactly how it is done. Make sure that the Accumulator actually gets the "final fill" from the onboard tank backflow and it'll work great.

David S
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Old 06-24-2012, 12:08 PM
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Default RE: JMP Accumulator - tips?

Thanks for the reply!

Dave
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Old 06-24-2012, 12:37 PM
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Default RE: JMP Accumulator - tips?

I just fueled up all the tanks through the Accumulator the first time, making sure not to get any air in through the fill line when I capped it off, checked for leaks and eventually flew it. No problems ever since. Mine is mounted vertically.

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Old 10-15-2012, 02:54 AM
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Default RE: JMP Accumulator - tips?

Mine is mounted vertically in a skygate hawk.  Yesterday I noticed bubbles going into the pump when I throttled UP.  There was not a single bubble coming INTO the ACCU from the on board fuel tanks, but several bubbles going up into the pump from the center feed line of the ACCU.  

I have not followed the above mentioned purging procedure.  I simply fueled up using the fuel line and started.  If we drain out a bit from the "fill lines" wont air go into the ACCU when you remove the tube to cap it off?  I dont understand why this is a must as other bubble busters dont need this method of purging.  Is the ACCU designed differently that it needs a reverse flow through the main tanks and the fill line?  Is it mentioned in the instruction sheet?

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Old 10-15-2012, 03:10 AM
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ddennison
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Default RE: JMP Accumulator - tips?

I pinch the line afte reversing flow (draining to purge) to cap it without air going back in the line.
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Old 10-15-2012, 03:34 AM
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Default RE: JMP Accumulator - tips?

OK i understand this.  Do you do this "pinch" with other bubble traps as well?  Is this a must with all air traps?  Or only the accu.
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Old 10-15-2012, 05:01 AM
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Default RE: JMP Accumulator - tips?

I do. I just bend the tubing and place the stopper in.
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Old 10-15-2012, 09:53 AM
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Default RE: JMP Accumulator - tips?

I installed a little jetcat valve inline with the drain line between the accumulator and the plug, originally as a "belt and suspenders" strategy in case the plug on the fill line leaks (which is a fatal issue...since the bubble trap .. anyone's .. will empty first), but find it very useful to make sure NO air ever gets into the line .. just shut off the fuel can pump when tanks full, then shut the jetcat valve, then plug the fill line at your leisure :-)

Did it on one of my more expensive planes, and have been replicating across the others since it works so nicely.

Agree 100% that the JMP accumulators are nice and 100% trouble free. BV states correctly that you don't get the diagnostic value of seeing a UAT collapse to show fuel plumbing impedance issues, and you don't see air over the fuel at the end of the flight .. but you CAN watch how long it takes for the line from the JMP to the last main tank to flow liquid after starting the fuel fill .. which tells you how much air was in there, if any.

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