Posted Thu Feb 14, 2013, 3:39pm Subject: Re: Automation of HX cooling flush?
Here's an awful MSpaint picture. :P
Again, knowing nothing about this particular machine I don't know if that's a straight through port on the grouphead or if there's something there the expansion valve needs... Or which side of the 3way valve that chamber is on.
Coffeenoobie Senior Member Joined: 11 Dec 2011 Posts: 2,950 Location: PNW Expertise: I like coffee
Espresso: N S Oscar Grinder: K30 & Vario W
Posted Thu Feb 14, 2013, 3:46pm Subject: Re: Automation of HX cooling flush?
Thanks for the drawing. That is what I thought you meant. That side only opens when the pressure get really high, so it would not really give you the flow temp. I think that why the guy in H-B.com drilled into the top of the group head and added the thermocoupler there. If I remember correctly where the red dot is.
(Click for larger image)
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Posted Thu Feb 14, 2013, 3:58pm Subject: Re: Automation of HX cooling flush?
The valve only opens under pressure, yes.
I'm saying connect the tee directly to the grouphead, attach the valve at the 90degree port so it can still regulate the pressure and put the probe straight through the tee so that it's surrounded by the water before the valve. Of course it could be that the expansion valve components aren't all internal to the valve and that it's dependant on something in the grouphead to function, in which case this wouldn't work. Unless of couse another fully contained expansion valve was used.
Posted Fri Feb 15, 2013, 8:51am Subject: Re: Automation of HX cooling flush?
Got a lot of work done last night.
Got my menu system working so I can change parameters from the machine and don't have to change the code and reupload to the controller.
Got an 'Auto Backflush' program working - pop blind filter and calfiza in and set the program and it will turn on 10 seconds, off 10 seconds as many times as are set in the parameters.
As the volumetric Appia has a microcontroller as a brain I knew there had to be a place on the controller board for me to draw 5 volts from to power my controller and I found it last night. So my controller doesn't have to be hooked up to the wall or my computer anymore (although it still is because I'm still tweaking things and want the data link to capture data - waiting for a bluetooth module to arrive from China to do this wirelessly in the future).
Had an idea last night to hook into the volumetric sensor so I can tell how much water is flowing through. I'm sure I could make use of that data somehow.
I'm thinking I have to play with my PID settings again as I think the flush is taking a little too long and using too much water, I can probably do better.
Took some video I'm going to try to upload to youtube (never done this before).
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