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.