The Dirty Portafilter

My corner of the Internet, mostly espresso related but occasionally life will interfere.

Thursday, January 26, 2006

Faema Rebuild Project, Boiler

Now that the groups are clean, it is time to disconnect the boiler. Once again I was relatively lucky and none of the boiler lines were stuck. Everything disconnected relatively easy and without much additional pressure. The only things that needed disconnected were the heating element electrical, pressurestat, boiler level sight glass and HX input lines. The boiler itself just sat on two supports, so once disconnected it just lifts out of the frame.

The heating element was the only part that required any effort to remove. The two element bolts needed a squirt of penetrating oil. A half hour later they released with a bump of the palm on the ratchet. The element itself was not in bad condition but I am still going to replace it. One of the ceramic element insulators had a crack in it. While it would probably work, why take the chance. Elements are only about $50.

The element markings were a bit puzzling. The element end-cap had a Faema stamp on it, but it only showed 1300W at 220v. That can’t be correct. A little math (volts X amps=watts) tells me that this should be running around 2600W given the amperage rating on the machine. The element was 390mm long and matches up perfectly to another Faema element, that just happens to be rated at 2600W, what my math suggests it should use.

Now it is time to descale the boiler. I had thought about capping all of the fittings and simply fill the boiler up and let it sit for a day. Metric plumbing fittings are nearly impossible to find in Dayton so finding plugs could take weeks. So I just decided to leave it as is and submerge the entire thing in descale.

I managed to find a drum at work that was the correct size. So I put twenty gallons of very hot water into the drum, added and dissolved my descale powder (yes, twenty gallons of water takes a LOT of descale agent) and submerged the entire works, including all of the other copper lines on the machine. If you submerge a boiler like this, you must rotate the boiler to make sure all of the air pockets are out of the lines and HX. Half way through the soak I flipped the boiler so and remaining air would shift and expose the entire works to the solution.

Five hours later it was clean as a whistle. I was quite surprised it went that quick. So now it is time to drain the drum and rinse everything off. So I put on my jacket and elbow length chemical resistant gloves and drag the entire thing to the end of the driveway to empty it out.

About half way through draining the drum it happened to dawn on me. It is 11pm, dark, I am standing at the end of my driveway warring a jacket and large black chemical gloves emptying out the contents of a big red drum that is emblazon with big yellow letters ‘HAZARDOUS WASTE’. If the police drive by, they may not find the humor in the situation. So I quickly empty the drum, grab the garden hose and thoroughly flush out the boiler and lines, rinse out the drum and get back into the garage.

I now have a very clean boiler. Not a spec of scale in it. I was going to wash the exterior a bit more with some Joe-Glo but there is really no need. I plan on insulating the boiler and there is just no need to have it spotless on the exterior.

Friday, January 20, 2006

Faema Rebuild Project, GroupHead

I have recently become the new owner of an old and very used Faema two group commercial espresso machine. It appears to have been sitting for a while and was very dirty, but appeared mechanically intact. So I decided to start another project and rebuild my first commercial heat exchanger.

As you can see, there was going to be a lot of scrubbing involved. I decided to do a complete frame up rebuild. Everything gets pulled, scrubbed, de-scaled, polished, repainted and reassembled.


One quick note. Some of the photos are mediocre at best. The strobe flash on my digital camera burnt out so I have to shoot without a flash. That means low F-stop and shudder speeds. Some of the photos may be slightly blurry because of that but I did my best with what I have.

GROUPHEAD REBUILD



First thing that gets pulled and rebuilt is the grouphead. These are a variation of the E-61 group. The groups were held on with two bolts and the two thermosyphen lines. Luckily, the thermosyphen lines unscrewed relatively easy. I believe it was a 21mm bolt head, a slight bump from my palm on the end of the wrench and off they came.
(the black box on the group stem is an electronic solenoid to open and close the 3 way valve)



After disassembling the lower stem/valve portion of the group, it was time to pull the shower screen and gasket to see what horrors were in store for me. I have an E-61 Isomac but it is less than a year old, so this is the first time I have removed this type of screen. I tried to pry up the screen with a screwdriver to no avail. So I decided to pry up the gasket. I inserted the tip of a small slotted screwdriver in the outer edge and pried up. It is just like opening a can of paint. It came right off.


Then I almost fainted! How on Gods green earth could someone let a machine get this bad. Both groups were in equal states of filth. It was at this point that I started to question weather or not I wanted to try rebuilding this machine. I took a deep breath and assured myself that it is just coffee residue and will clean up with a good scrub.

So that is exactly what I did. After disassembling the groups I soaked them both in descale solution over night. The 3 way solenoid channel was caked with buildup and required additional attention. After a bit of scraping and more soaking it came clean.

I have to point out one interesting thing. Descale solution does not remove the oily residue. While the inside of the groups was clear of any hint of scale, the dispersion screen was still black with buildup. So an overnight soak in some Joe-Glo detergent. Now that did the trick. After a bit of scrubbing and scraping I was rewarded with two shinny group heads. I installed new O-rings and reassembled the groups.

Tuesday, January 03, 2006

Rotisserie Roaster Died, We Can Rebuild It, We Have The Technology…

I lost a good friend a few days ago. Why, owe why do the good ones die young? My hot rod rotisserie oven roaster motor died mid roast. No squeaks, grinding, groaning, it just stopped. Granted, with my mods I regularly run 550-600f in an oven that was designed for 400F use. Combine that with a motor that is only a half-inch from the inner shell; I should have expected it to eventually burn out.

So off to the giant surplus parts store I go. I found an 115V motor and a reduction unit to reduce the rotation speed to 15rpm. I mounted the motor on the exterior of the unit to get it away from the extreme heat. I had to build an extension shaft to traverse the gap from the exterior to the interior (long threaded stud with the rotisserie receptacle end welded to it). Got my motor mounted, attached my start capacitor and fired it up. 5 minuets later, the motor stopped, my heart dropped.

After a bit of tinkering and testing, I realized that there was a thermal switch in the motor that was shutting it down. So I pulled the motor apart, removed the breaker and rewired. Now it will run until it burns up, not good either. So off to the surplus store I go again. This time I picked up an 115v squirrel cage fan, 4 heat synchs and a power block.

I pulled the motor apart again, drilled and mounted the heat synchs on the motor case and grind down the studs inside the motor casing. I also drilled a few strategically placed vent holes in the casing to aid cooling. Then I mounted the fan above the motor to cool it and the heat synchs and attached the capacitor.

Then I mounted the power block and wired everything to it. That way, when the rotisserie is on, so is the fan. Looks big, gangly and most defiantly home built, but boy does she work good. I am getting a faster roast with the higher drum RPM and it sheds off chaff better as well. Hopefully it will last a couple more years.

Sunday, January 01, 2006

Happy New Year

Happy New Year World. Let’s hope 2006 is a better year than 2005 was. I need an espresso.

Aluminum Backing On Your Boiler Insulation

A few days ago I powered up my machine, but after a few moments, I noticed that it was not heating. Grate! Something else that is broken. I pulled the machine and disassembled expecting to find a blown heating coil, burnt electronics or some other disaster. After a bit of quick diagnostic, I ruled out most everything, then I checked the thermal fuse, which should have been my first check. To my horror, I found this!!


Apparently, the foil backing was close enough to the connector that I got some arcing. Burnt the connector to a crisp and blew the thermal fuse. I replaced the fuse and connector, and then put some insulating electrical tape around all of the electronic fittings to prevent it from happening any where else.

I also removed the insulation from one end of the boiler. On my Isomac, most of the electronics are on one end, so I removed the foil backing from the insulation on that end just as an added measure of security.