The 1974 to 2000 group was practically unchanged throughout the years it was made. As has been pointed out before, it is heated by having a small passage to the steam filled part of the boiler through which live steam passes and then condenses in the space above the piston. This keeps the top of the group at the reservoir temperature, normally 116 to 120 degrees. In order for this to work, the air in that space must be expelled. On the two element models this involves simply raising the group handle to the top whilst steam is being expelled from the pressure release, preferably before turning off the second heating element. This results also in running very hot water into the bottom of the group, with the burst of steam during the bleed that enters the bottom of the group also heating it quite a bit.

On the pressurestat models the boiler needs to be bled by opening the steam vent when the element switches off. Normally the space above the group is bled at that time, so that while the steam is pouring out the steam vent, one raises the handle to the top, and some hot water comes out while the air above the piston is forced back into the boiler to be swept out. It is not nearly as hot as with the two element models at this point, and it does NOT heat the bottom nearly as much. If one wait until the heater turn off again and immediately pull the first shot it is apt to be "spongy" because the water that entered the bottom of the group was not hot enough to produce the massive amount of steam it does with the two element models. With the group too cold the water does not have enough vapour pressure to drive the air out of the space below the piston, and you get a spongy pull. I find you normally need to wait about two or three minutes before making the first pull with these, whereas with the old two switch models one could make the first pull right away.

I was impatient this morning, and suddenly realised that the waiting could be eliminated. I bled the 1999 machine when the pressurestat turned off the element, as usual. (On many occasions in the past I have measured the temperature with my probe cap to see what the temperature is at this point, it is normally about 102 degrees.)

As soon as the element turned off, I raised the handle again and allowed just a few millilitres of water, now at 118 degrees as it was discharged, to escape into the group. I immediately put the filter basket with the pressed coffee into the portafilter and made the first shot. It was NOT spongy at all! And I did not have to wait two or three minutes for the bottom to of the group to get hot from the steam above the piston!

This is a very helpful post, as have been your others regarding steam heating of the Europiccola group. A few points:

1) Following an earlier post, I've been raising the lever twice to 3/4 height while bleeding the boiler. This time you have suggested one full pull to the top (which also allows a little water to come through). I suppose the latter idea is to bring a little heat further down the group.

2) I have a temperature strip mounted towards the bottom of the group and I can see the heat travelling down the group as the tops of the bars turn green before the bottoms. This has also allowed me to see the difference between waiting a few minutes between the first raising of the lever, or lifting it again when the boiler comes back up to pressure. It works as you say: sometimes I prefer the wait if I'm doing something else, other times I go for the quick heat.

3) I note that the coffee-making instructions that came with my (then new) pressurestat 1999 Europiccola do not mention bleeding the group of air, only the boiler. They do say this, however:

"... after the group is [back] up to pressure, raise the lever a half stroke and then pull it down; repeat this operation two or three times to allow the group to warm up."

Do you suppose this is to evacuate the air from the chamber and allow in some steam? There is no mention of opening the steam wand to allow the air somewhere to go.

I suspect that they never updated the instructions when they went to the machines with the pressurestat. It was not necessary to get the air out of the boiler with the two switch machines because the air got swept out when the steam began to be released from the pressure relief valve. I have made a special boiler cap with a thermometer well. With the pressurestat machine the temperature seems to be only a bit over 100 when the pressurestat turns off. When the steam valve is opened the heater turns on instantly and the temperature climbs to about 116 or 117 in a minute or so. One really needs to raise the lever whilst the steam is being released so that the air that is brought into the boiler by raising the group handle can escape from the system.

When I put the temperature measuring cap on an older two switch model, the pressure release valve begins to hiss a bit at about 100 degrees and, as the air is expelled, the temperature keeps climbing until about 118-120. That is when I raise the handle on that machine because I know the air has been purged from the boiler.

It really is amazing how fast the top of the group heats once one has raised the lever after the machine is hot! Then the heat conducts downward toward the brewing area.