I'm current rebuilding a Faema Compact A 1 group from 1992. Tear down is complete, frame is out for powdercoat, and parts are on order. All gaskets will be replaced as well as a new steam wand to replace the frother thingy it came with, sight glass window, overpressure valve, thermal cutoff and boiler gauge.

When I picked up the machine the overpressure valve was removed and damaged but I was assured that except for "the leaky thing on the top" everything was in working order. It was otherwise complete and in reasonable shape for 20+ yrs old so I brought it home. After digging in a bit it was clear this machine had other issues including a fossilized oyster in the sightglass and a lower sightglass return tube with an amature (lead) solder repair. I didn't have the patience to wait for a replacement valve and preform a diagnostic test so, camera in hand... the fun began.

The tear down was fairly straightforward, any issues I came across were were usually fixed with advice found in these forums... the only real difficulties that remain are a stuck water valve and a heating element that doesn't want to leave the boiler after I snapped off the heavily corroded bolts. Some easy-outs should fix that tonight.

As I wait for Brown to arrive with my parts, I would like to test some of the other components before re-assembly;

How do I know the Sirai pressurestat works?
How do I test the heating element before installing in the boiler?
How can I test the Ulka vibe pump?
How do I know the Parker 3 way and the mains 2 way solenoids are working?
Is there any way to test the flowmeter?

Electrical is not my strong point, but i do have a multi-meter ready to rumble. This is a 120V machine.

Your advice is much appreciated as this is my first rebuild after months of lurking in the HB forums. Some pics before dissassembly are below.

JC

Front all buttoned up


Sight glass & boiler gauge


Thermosyphon, 3way solenoid, flowmeter


Boiler missing overpressure valve replaced with teflon tape


Rear OPV, Ulka pump in behind, Sirai pressurestat in the top left, dirt floor

How do I know the Sirai pressurestat works?
How do I test the heating element before installing in the boiler?
How can I test the Ulka vibe pump?
How do I know the Parker 3 way and the mains 2 way solenoids are working?
Is there any way to test the flowmeter?

You can rig up a 110 volt pigtail with alligator clips, and put it into a switched outlet. Use this to test the coils on the solenoids to see if they actuate. Put a hose on the Ulka intake with the other end in some water, and run the pump to see if it pumps.

On the heater, measure the ohms. R should equal roughly 12,100 divided by the the machine's wattage (e.g. 12 ohms for 1KW, 6 ohms for 2KW)

The Sirai is more complicated. It's a pressure actuated switch. You can test the continuity on the normally closed contact, which is the one you use. But you'd need a bellows, or a hookup to some pressure source, to see if you set it to turn off when the pressure goes above 1 bar or so. If you have another espresso machine, you can use a hose to hook it to the steam wand and see if you can adjust it to click on and off in tandem with that machine's pstat.

No clue on the flowmeter.

another_jim wrote:You can rig up a 110 volt pigtail with alligator clips, and put it into a switched outlet. Use this to test the coils on the solenoids to see if they actuate.

I'm assuming that I don't need the mechanical core in the coil for this test... so i'm just listening for clicks?When I opened up the mechanical core for the 3 way I found the "nucleus" spring-ontop-of-spring thingy to be slightly corroded but moving freely. If the coil actuates under power should I be concerned with the mechanical core?

another_jim wrote:On the heater, measure the ohms. R should equal roughly 12,100 divided by the the machine's wattage (e.g. 12 ohms for 1KW, 6 ohms for 2KW)

I believe my heater to be 1500W so that means i'm looking for about 8 ohms of resistance. Can I assume that an infinity reading equals a dead element?

On the pstat - I think i'll forget about trying to test it. Should I replace the diaphragm anyways or wait and test it out first?

Thanks for your help Jim i'm going to give your suggestions a try this evening.

JC

Solenoids: You need the iron core on the electromagnet to check it, since that is what moves. I'm mechanically hopeless, so I don't know how to test the valve seating without actually putting them in-line.

Heater: 1500 watts is around 8 ohms. An open circuit shows it's burned out.

Pstat: if you are replacing the diaphragm, test the contacts -- look for a closed 0 ohm circuit on the NC. Any positive ohmage on the NC side shows carbonized contacts. On the Sirai, they can be replaced too.

Best of luck, it's a handsome looking machine, and can pull great shots.

I do all of my initial testing with the heater circuit disconnected. The elements are easy to wreck if they are not immersed in water.

You do not need the core in the solenoid to check its function. They are simple little devices and when you hit it with power, it will make a loud click. I sometimes take the 3-way cores apart to see if they look clean.

Do you know if it was electrically sound when it was last used?


Tip: Put the whole machine over a sink or large Rubbermaid tub when you first fire it up. Water may spurt out from a number of places and make a huge mess on your workbench. I take two chunks of 2x4 and make a bridge across my laundry sink that the machine sits on. Please consider your safety as you have electricity and water in close proximity while doing this.

Jim pretty much took care of your questions. The pressurestat, you could use an air compressor with the regulator turned way down to see if the diaphragm clicks over. You can also get rebuild kits for those. They are known to have a drifting deadband, larger swings between off and on as they age. Personally, I would get a rebuild kit, or seeing how that one is as old as the hills, just order a new one and not worry about it. I had the same gray box in my two group Faema when I did a rebuild on it. It still worked but since I was doing so much work on it to begin with, I just ordered a new one from the start.

Your heater, do not connect it to power when you put it back together. Let it fill the boiler, run some water through the grouphead, then unplug it when there are no obvious leaks under pressure (backflush with just water and look for squirters) then hook up your heater and let it heat.

Flowmeter, not a lot of help. I know they output a signal for the brain box. You could take the meter apart and make sure the impeller spins free, then hope it all works. Flowmeters are expensive. If it is dead, you could just disconnect it and use it as a manuel machine. Press a button to turn it on, press again to turn it off.

One last thing, your heating element, get the Teflon gasket if it is available, not the paper.

Thanks for the help everyone. I was starting to worry about the start up procedure so i'll follow the your process closely leaving the heater connection for last.

As far as I know the wiring is all sound. It looks to be very clean, with no corrosion in the main power box. The brain circuit board also looks clean and all the solenoid connectors came off easily. No electrical tape or signs of tampering so I should be in good shape.

I took the cap of the flowmeter and the impeller spins freely. The chamber was very clean so I dropped the lower part in citric and left the cap with electronic bits in tact. It looks like it should be fine.

As for the pstat I think I will just look for a replacement... with a mfg date of 1992 its time is up. A wide deadband is a variable I do not need to introduce.

In testing the resistance of the element last night and showed a consistent 10 ohm reading (I think its actually a 1300W element). I'm still having trouble removing it from the boiler. 2 of the 3 zinc mounting bolts have completely fused with the heater's base and broke off in my socket wrench. The whole thing is soaking in citric so i'll see if it will give up tonight. Teflon gasket is on the way. Replacement overtemp added to the cart.

Probably not much action until UPS shows up and the frame and control box returns from the powdercoater.

JC

I have been considering adding a brew pressure gauge. Since the boiler pressure gauge needs replacement anyways I may as well fit a double scale in its place.

I've noticed a capped-off fitting on the water mains valve, where the stainless tube leaving the Ulka pump enters the valve. You can see it in the second picture from my first post on this thread, bottom left on the rear side of the valve beneath the drain tube. Is this is a suitable place to connect? I'm assuming that the closer to the group the better, but if I take a reading of 9bar from the valve could I interpret a 8.5bar reading at the group?

Hi, nice job so far.Here's a link to a re-build of another compact.I found it very helpful during my re-build, especially the water distribution valve.The fitting you mention would indeed be a good place to fit a brew pressure gauge

http://www.homeroasters.org/php/forum/v...#post_2473

another_jim wrote:No clue on the flowmeter.

Paul Pratt has an excellent writeup on his site, espresso-restorations.com. There is also a section dealing with the various major components and testing them. Here's the one on flowmeters:

http://www.espresso-restorations.com/flowmeters.html

Hope it helps. If nothing else, it's really fun to see his projects detailed!