I have confirmed with the Olympia factory the proper information to properly setup a Cremina during maintenance or overhaul.

Adjustment of the pressure regulator:

The pressure regulator should be set to .8 to 1 bar pressure. The pressure is most easily measured by attaching a gauge to a dummy boiler cap. In this way, no plumbing needs to be disturbed. It is also possible to set the pressure by measuring the boiler temperature using a thermocouple probe inserted through a boiler cap into the pressurized water. Tables can be used to correlate the temperature to the boiler pressure. If the regulator has never been disturbed, it should still be in adjustment.

Safety Valve Setup:


Preferred method:

Measure the position of the adjustment and record it before disassembly. After seat replacement, reset the valve adjustment to the original setting. This setting varies little from unit to unit and seems to vary little with age of the machine.

Back up method:

If the correct setting has been lost, or needs to be reestablished, follow this procedure. Establish that the pressure regulator is correctly set as above. If the regulator has never been disturbed, you can assume that it is correct. Adjust the safety so that it just releases steam. Now increase the adjustment one quarter turn beyond the point the steam just stops coming out of the valve. This is the correct adjustment.

Talk about timely. I've just completed a full seal replacement on a Cremina whose pressure was very off. Since that's the case I also want to double check the pressure relief valve. Thanks to your highly informative post I now know how.

bobcraige wrote:The pressure is most easily measured by attaching a gauge to a dummy boiler cap. In this way, no plumbing needs to be disturbed.

Makes a lot of sense. What hardware did you use to set up the dummy boiler cap? Do you have any pix?
Jon

Hi Jon

I do not have any photos of such a tool. You can find such a picture in the following thread by scrolling down through the photos to the fourth photo down:

http://www.home-barista.com/forum...-factory-t839.html


The tool would be made by drilling a tapping a properly fitting boiler cap to accept the pressure gauge.

I have just replaced the seal in my safety valve and can now offer some specifics that may be of interest to others:

Tools required:

Boiler neck nut-30mm, preferably a 30mm socket

Safety valve cover 17mm, preferably a 17mm socket or box wrench

Safety valve body 17mm-17mm open end wrench

Safety valve adjustment screw-5mm allen wrench

A pair of calipers with depth measurement capability.

To expose the safety valve, remove the boiler cap, then unscrew the boiler filler neck nut with the 30mm wrench. You may need to manipulate the circular stainless steel drip tray until you are able to release it from the filler neck threads. Now lift off the drip tray, then the rectangular stainless steel top cover and finally lift off the machine housing.

The safety valve is located on the right side above the sight glass. There is a 17mm cap at the top. Using a 17mm open end wrench on the valve body, remove the cap using a 17mm socket or box wrench. Use the open end wrench to absorb the torque you are applying to the cap so it is not transmitted into the machine and perhaps the sight glass. You can now look down into the valve body and see the adjusting screw. Take a depth measurement with pair of calipers from the top of this screw to the top surface of the valve. With a felt tip pen, make a reference mark on the top of the screw and a matching mark on the outside of the valve body. If you do not have a caliper, you can simply count the number of turns as you back the screw out using a 5mm allen wrench. When the screw is out, you will see the spring. Lift out the spring and you will see the valve seal assembly at the bottom of the valve body. Using a wooden tooth pick, you should be able to lift the valve body free. You may want to turn the machine upside down to get it out. Before turning it over, put the cap back on the boiler and remove the drip tray and the portafilter.

Once you have the valve seal assembly out, pry the old seal out with something soft such as your fingernails or a tooth pick. Now insert the new seal in the holder, pushing its edge carefully into the holder. Screw the valve seal assembly back to the previously measured depth. My valve was 3.0mm (.118 inch) below the top of the body. When replacing the cap, again use the open end wrench on the valve body to absorb the torque of tightening the cap. Reassemble the machine by revering the procedure.

When I reassembled my machine, I found it leaked initially with the new seat-worse than before. When I heated it up the second time, the leak was gone. I assume that this was due to the new seat settling in. Before you panic and take it all apart again, give it some time to see if it stops leaking after replacing the seat.

bobcraige wrote:The pressure is most easily measured by attaching a gauge to a dummy boiler cap. In this way, no plumbing needs to be disturbed.

Bob, this was a very helpful posting, and timely for me as well. My replacement gasket and seals set arrived in the mail today from Switzerland.

A 30mm socket is near the top of my shopping list. Until then, I can't accurately measure the thread pitch on the boiler mouth. Its major diameter is 25mm. Do you happen to know the thread pitch? Perhaps there's a female-female brass adapter that could attach on one end to a pressure gauge and on the other to the boiler mouth? Then there'd be no need to drill through a boiler cap.

Regards
Timo

I measure a pitch of 1.50mm for the filler neck threads. Let us know if you find a fitting and where to get it.

timo888 wrote:A 30mm socket is near the top of my shopping list.

A 30mm socket for a one time application is sort of overkill, especially as there are workable alternatives.

Just use a crescent wrench big enough to fit. If you're worried about scratching the metal, put some duct tape on surfaces that might get scratched.

I just use strong finger pressure to tighten the nut on mine, and it works fine to hold everything together...Rod

bobcraige wrote:I measure a pitch of 1.50mm for the filler neck threads. Let us know if you find a fitting and where to get it.

A local plumbing supply shop has told me they're getting in some brass reducing couplers on Monday. Cost about $10 each. I will report back on the results. Thanks for taking the thread-pitch measurement.

Regards
Timo

RCMann wrote:A 30mm socket for a one time application is sort of overkill, especially as there are workable alternatives.

Just use a crescent wrench big enough to fit. If you're worried about scratching the metal, put some duct tape on surfaces that might get scratched.

I just use strong finger pressure to tighten the nut on mine, and it works fine to hold everything together...Rod

But shopping for tools is half the fun. I don't like to buy them new, though, which is why the 30mm socket is still on my list and not already in the drawer

Regards
Timo

In "Enoch and the Gorilla," one of Flannery O'Connor's blackly comic short stories which were set in the Deep South in the 1950s and were typically about rude awakenings in the lives of her characters, a guy named Enoch, who is sort of a simpleton, decides to set out on an adventure that will involve a dramatic change to his physical appearance. Enoch has been inspired by a truck that pulled into town with a loudspeaker advertising "Gonga, Giant Jungle Monarch". Boys and girls will be able to line up and shake the gorilla's hand later that day, for a dime. Enoch tells the waitress at the diner where he's a regular that he has big plans, and that she won't be seeing him much longer "like this" -- meaning as he looks now. The waitress stands there, one hand on her hip, the other holding up a pot of coffee. "Any way I won't be seeing you," she replies, "is fine with me."

Now that anecdote does mention coffee, so it's not completely off-topic, though it was probably a Bunn burner. Not too many diners in small towns in the American South had lever machines in the 1950s.

Anyway, I had my own Enoch-like put-down this morning, after searching for several days for an adapter to connect the 1/4" NPT thread on the pressure gauge to the 25mm(?) metric thread on the Cremina's boiler neck. I find a company called AdaptAll in Ohio. If they don't have this coupling, nobody will. I tell the tech about my own big plans to connect a pressure gauge to the boiler neck of my Swiss-made espresso machine. He replies "Good luck!" I ask him, why? He says 25mm metric pipe fittings are rare; they're usually 24 or 26. I tell him that the exact measure of the thread is 24.7mm and ask him if that would be considered a 24mm or 25mm thread. "You can consider it anything you like."



Regards
Timo