I did some more work today on my old single group Grindmaster Espressimo machine. The Espressimo heats the group head with a heating element that encircles the top of the group. Mine went out as heating elements like to do. So instead of buy a new calrod element for about 30 bucks (though I didn't think it would be that cheap), I decided to heat it with steam - more like an E61. I simply extended the copper tubing that went to the vacuum breaker valve and routed through the cavity in the group head that used to be occupied by the heating element. This involved only one part, some tubing, so it was simple in conception, but getting it in there required the moving lines and taking the group apart.

The other project I did with it was to add a cold water mixture to the americano spout. My hot water comes out boiling and sputtering. To control this and dial in the temperature, I spliced the cold water line and the hot water line to the spout interrupting the flow with a stop cock valve. This way I can control the flow of cold water into the mixture.

The only snafu was that the hot water line coming from the boiler cracked and we nearly had to take everything apart to replace the heating exchange coil. We managed to jury rig it tolerably enough.

The mods are all done for now. Someday I plan to replace my boiler pressure gauge with a dual manometer.

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Comment by Chris Hooton on August 10, 2009 at 9:44am
update: my rig in the group head doesn't create a proper thermosiphon. It only heats the group brass when the vacuum breaker valve is open.
Comment by Chris Hooton on March 24, 2009 at 8:10pm
The cold water line feeds both the americano spout and the group head. That is why if I open the spout when the brew cycle is running the pump will actually run out of water to push. Since I have to leave the spout closed anyway, the cold water splice doesn't affect the group temp. The two lines coming off the cold water line form exasperate heat exchanges. If you look in the boiler (and the plumbing is original) you should find the americano spout line making a short tight coil around the heating element and the group line making a longer coil closer to the sides of the boiler.

The stop cock valve was a simple 1/4 to 1/4 inch flare valve from the hardware store. I'll post a picture of the plumbing if I remember.

The group heads have to operate at a higher temp. Check to see that it is coming out between 192 and 202 degrees F. Also check to see if the boiler pressure is correct. If these are too high, you'd want to adjust the pressure stat. There should be a screw to turn to adjust. The manual says 1 turn = 1 psi.

If that is correct the sputtering could be a bad pump... as I recall that is what mine was doing before i replaced it. To check this, attach a pressure gauge to the portafilter, it should read around 125 psi. If it doesn't get any where near it replace the procon pump (or have it remanufactured.)
Comment by Steve on March 24, 2009 at 9:12am
Chris, Does adding a cold water mixture to the americano spout also have an effect on the water going to the group head? Does the line going to your americano spout Tee off the same line that goes from the heat exchanger to the group head? I have the 2400 and that's how mine is setup. I have found that the water coming from my spout also sputters. Sputtering water means the temp is too high. The water coming out of my heads also sputters. Which means that water temp is too high too, if I am thinking through it correctly.
What kind of stop cock valve did you use?
Thanks for the info.
Steve

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