Why does the idle temperature drop during the day? - Page 2

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decaf_Ed

#11: Post by decaf_Ed »

BradyButler wrote:Thanks to all for an educational post on thermosyphon stalling due to flash-boil.
Hopefully most HB readers are smart enough to not take my post above too seriously when it got to the part about colder areas not condensing as easily. Anyone who built and operated a still would probably know this, even if reading it the way it was written, after three double shots. Here in Minnesota we're still in the election cycle for our new governor, so pseudoscience, bogus reports from fictitious institutes, etc. are still in vogue, and you just hate to let go of that stimulating mindset.
-Ed

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BradyButler

#12: Post by BradyButler »

cannonfodder wrote: A funny story. I was working on my very first plumbed in rotary machine. I wanted to take the group bolt out to check for scale and clean the filter in the group. I turned off the machine and let it cool down for an hour. It was still a little warm but not hot. I started to unscrew the group bolt and a little water started trickling out. Figured it was just residual pressure so it let it dribble. A moment later it was still dribbling. So I thought that turning the bolt a little more to open the threads up would let the pressure vent faster. It kept dribbling. That's odd, I thought. So I unscrewed it a bit more and took the bolt out. Then I had a fountain of water spraying everywhere in the kitchen. After a moment of what the #$%^$ is going on?!? It dawned on me. This is plumbed in, you did not turn off the water. That is the mains pressure doing a garden hose impression. Last time I ever did that.
Sounds familiar. That's the other reason I though that the hX loop was under mains pressure :).

That bit of residual pressure is a pain, sometimes it seems like you wait forever for it to stop dripping. I've taken to relieving that pressure by opening the manual fill valve briefly after turning off the water valve, then verifying that things are at zero on the dispense pressure gage prior to cracking open any fittings.
LMWDP #379
Carolina Espresso Services - "Quality Service for Espresso Equipment"

Ken Fox

#13: Post by Ken Fox »

cannonfodder wrote:
A funny story. I was working on my very first plumbed in rotary machine. I wanted to take the group bolt out to check for scale and clean the filter in the group. I turned off the machine and let it cool down for an hour. It was still a little warm but not hot. I started to unscrew the group bolt and a little water started trickling out. Figured it was just residual pressure so it let it dribble. A moment later it was still dribbling. So I thought that turning the bolt a little more to open the threads up would let the pressure vent faster. It kept dribbling. That's odd, I thought. So I unscrewed it a bit more and took the bolt out. Then I had a fountain of water spraying everywhere in the kitchen. After a moment of what the #$%^$ is going on?!? It dawned on me. This is plumbed in, you did not turn off the water. That is the mains pressure doing a garden hose impression. Last time I ever did that.
The LM GS/3 Paddle is a machine where you can easily demonstrate this phenomenon when it is turned off but still plumbed in. If you move the paddle to the position that would normally allow mains pressure pre-infusion, it does not matter whether the machine is turned off or if it is on, the water will flow freely through the group. This is a convenient way to flush out the "stale" boiler water if you are just returning from an extended period away from home when the machine has been turned off.

Of course, I turn off the water at a valve before it would enter the machine when I am away from home and the machine is turned off. To do otherwise would be to invite a rare but possible flooding disaster.

ken
What, me worry?

Alfred E. Neuman, 1955