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Re: Boiler/PID problem

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  • Tex
    ... a) The 3-way solenoid is in play when the shot is being pulled, but the refill solenoid is closed, so the pump is pushing water through the HX, not into
    Message 1 of 12 , Jul 31, 2010
      --- In BUG-is-Bunn@yahoogroups.com, "jack_burien" <jack_burien@...> wrote:
      >
      > I removed the innards of the incoming water solenoid and cleaned same. When adding water to the boiler, the solenoid can be felt and heard opening and closing. It cannot be felt when pulling a shot. I trust this is the way it should work.

      a) The 3-way solenoid is in play when the shot is being pulled, but the refill solenoid is closed, so the pump is pushing water through the HX, not into the boiler.

      > I ran some tests using a blind. I've set the pump pressure in the green zone of the gauge, realizing that it isn't all that accurate. However, after pulling a shot or using the blind, the pressure immediately jumps up to about 12 bar and then over a 15-20 minute period bleeds back to the incoming line pressure. Is this normal? I'm going to reset the pump after I finish putting together my test pressure porta-filter.

      a) As for the group pressure gauge? It's too unreliable to base any theories on. If it was accurate though, you'd see an immediate ramp up in pressure as soon as the pump is turned on. The readout should be constant as long as the pump is on, then drop back to zero after the 3-way valve releases the group pressure.

      If the group pressure isn't returning to zero after the shot then I would suspect the 3-way valve. If it fails, the group pressure will remain high until it can bleed off through the puck in the portafilter.

      Take the 3-way valve apart and clean it and check the coil. If you haven't already done so, I suggest removing the entire group for a thorough cleaning.

      Tex

      > Allowing for an inaccurate pressure gauge, what is the relief valve size you have installed? I've got a 1.6 bar. Is this too low a relief? jack pulling shots in burien :-)
      > --- In BUG-is-Bunn@yahoogroups.com, "Tex" <Texas_Coffee@> wrote:
      > >
      > > WOW!
      > > 1st: The line pressure should not exceed 1 bar.
      > > 2nd: Here's a table of bar & temp conversions;
      > > Boiler Water temp
      > > pressure (Fahrenheit)
      > > (bar)
      > > 1.0 253
      > > 1.1 255
      > > 1.2 257
      > > 1.3 259
      > >
      > > 3rd: The pump/group gauge will only display when the pump is activated and there's a puck in the filter or a pack flush filter in place.
      > >
      > > 4th: I NEVER trust a gauge that's not certified accurate!
      > >
      > > 5th: Check the 2-way refill valve. Disassemble it and test the solenoid and clean the piston and barrel. You should be able to hear the valve activate when the coil is powered up.
      > >
      > >
      > > --- In BUG-is-Bunn@yahoogroups.com, "jack_burien" <jack_burien@> wrote:
      > > >
      > > > This is a bit lengthy, but is what has been going on.
      > > > I reset the Cal3200 and used auto-tune. I also checked the cold (32) and hot (212) temps. Both were accurate. Next I installed a new gauge and installed a "T" to the thermocouple fitting so that I could monitor the boiler pressure. I realize is isn't spot on, but I felt is would give me a general idea of where the pressure was.
      > > > I now see the boiler pressure go up with the relief valve popping where is should. The temp is about 245F.
      > > > With the temp set at 241F is show about 1.4 bar.
      > > > When should the head pressure show 8 bar? Is it when the boiler is hot b4 pulling the shot? Hopefully that is the case, as that is when I see the gauge in the green zone.
      > > > I'm also considering a failure of the valve controlling the incoming water and wondering if the line pressure is effecting the boiler? I realize I'm asking some dumb questions, but not really sure where to go from here.
      > > > The incoming water pressure is about 2 bar. I have a regulator on the incoming line with an accurate gauge on the regulator.
      > > > jack in burien :-)
      > > >
      > > > --- In BUG-is-Bunn@yahoogroups.com, "Tex" <Texas_Coffee@> wrote:
      > > > >
      > > > > This will verify that your PID is calibrated:
      > > > > -------
      > > > > Ice mixed with water and allowed to rest for a few minutes will give you 32°F within millidegrees. Be sure to stir it every half minute or so to get the thermoclines well distributed.
      > > > >
      > > > > Boiling distilled water at sea level will give you 212°F fairly accurately, less 1°F (for your stated accuracy) for every thousand feet of altitude you are above sea level up to a few thousand feet.
      > > > > -------
      > > > > When you installed your PID did you reset all baseline parameters? This is done on Level 3, Reset=All. Did you use autotune or did you set the PID parameters yourself?
      > > > >
      > > > > It may be that your pop-off valve is kaput, but check the PID first.
      > > > >
      > > > > Tex
      > > > >
      > > > > --- In BUG-is-Bunn@yahoogroups.com, "jack_burien" <jack_burien@> wrote:
      > > > > >
      > > > > >
      > > > > > I'm at 212F because the new relief valve kept going off at 230F, down from 245F where it went off also. I'm using a Cal 3200 and I haven't calibrated it because I couldn't find instructions for calibration in the Cal 3200 manual. The thermocouple is in the hole that once was the pressure feed for the gauge. I'm using a 6 inch probe. Is there a chance the feed water probe is too low and there isn't enough water in the boiler? Just a thought. What should the probe length be?
      > > > > > I still haven't figured out why the temp rises from 212 to 229 after removing the top cover. During that time, the heater does not go on.
      > > > > > I'm guessing the temp controller is not properly set up. A bit of help in that area, please. I can certainly remove the thermocouple and controller and set up a calibration test. jack in burien :-)
      > > > > >
      > > > > >
      > > > > > --- In BUG-is-Bunn@yahoogroups.com, "Tex" <Texas_Coffee@> wrote:
      > > > > > >
      > > > > > > I have my PID set to 252 degrees Fahrenheit, so why are you setting yours to 212? What controller are you using & where is the thermocouple placed?
      > > > > > >
      > > > > > > Tex
      > > > > > >
      > > > > > > --- In BUG-is-Bunn@yahoogroups.com, "jack_burien" <jack_burien@> wrote:
      > > > > > > >
      > > > > > > > More info. I dropped the temp setting to 212 F and put all the covers on and let the machine stabilize. Then I took the top plate off and watched the temp climb to 229 F without the heater turning on. Does anyone have any idea as to what is happening? Could the controller be bad? I'm at a loss. jack in burien :-)
      > > > > > > >
      > > > > > > > --- In BUG-is-Bunn@yahoogroups.com, "jack_burien" <jack_burien@> wrote:
      > > > > > > > >
      > > > > > > > > After installing the PID, I'm finding that I can't maintain even 230 F with the machine covers on. The relief valve (1.6 bar) pops off. Can anyone suggest a higher relief valve or suggest a solution to the problem? tia jack in burien :-)
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