Here are some pics of the Faema family. It is surprising to see such quality in this relatively unknown machine. It sports a 300 ml brass boiler, adjustable over pressure relief valve, 3-way solenoid, 58 mm commercial portafilter, copper piping and steel braided water lines, a resettable thermal cutout switch.

These are more features than found in a Silvia and on par with the likes of an Isomac Venus (looks nearly identical inside) and the ECM Botticelli II (both $1000 machines).

This model Family has a common rotating steam valve, rather than the sliding steam valve. It is purported that this later model has an aluminium boiler, so beware.

Here are a few pictures to show you what it looks like and what's inside.

The machine



Heavy 58 mm commercial portafilter


Inside - the top of the boiler


The over pressure valve




The first shot tasted really good...

Hi Mal,

They used to retail for close to $1000, if I recall a few posts correctly. They are no longer in production, although there is a slightly later model available in Canada with a sliding steam valve and side access to the water reservoir. However, it purportedly has an aluminium boiler. Why they'd make such a radical engineering change, I don't know (maybe cost engineering ). Just beware. The model I have was supposedly in production between 1982 and 1992 or thereabouts.

Here's a link to the model available in Canada:
http://www.faemacanada.com/family.html

I got mine on ebay for $187.50... I saw one go a few months ago (same model but white colour) for $260ish so there's a few price points for you.

All is not roses though. It's a pretty errr, well less than aesthetically pleasing machine. Just note that the body is cast aluminium, not plastic. In fact it's one tough machine with very little plastic overall.

Worst point so far is the drip tray. It's far too shallow and difficult to remove and empty. It's almost a design afterthought.

Just a few more notes:

The group heats up really fast, maybe 10 min or thereabouts. The group head temperature cycles between about 91 and 96 deg C and responds to the heating element switching within a few seconds. The wierd thing is that the shot temperature seems to plummet; starting at a GH temp of about 93 deg C, the shot temp dropped quickly to about 88 deg C and fell to 84 deg C by the end of the shot (ristretto). Sure enough, the shot was sour. So this machine is designed to be operated near the top of the heating cycle.

What this seems to indicate is that the machine is designed to mix the cold feed water with the hot boiler water, similar to a HX machine. This is unusual, as boiler machines are usually designed to keep the feed water and brew water separate for as long as possible to maintain temperature stability.

Nevertheless, this machine is perfect for what I have in mind. I'll just have to crack the boiler open to see what's going on.

A drop in temperature from boiler  through portafilter will occur during the extraction because of temperatue loss through the cold grounds and because the group will also siphon off some heat.  

A big chunk of brass weighing several kilos as used in E-61 groups (the group on its own weighs as much as some entire cheap machines)  will give very stable temperature...whereas at the other end of the scale a thin  aluminium group with small aluminium portafilter will radiate it all away.

Further heat is lost as the coffee leaves the spout and collects in the cup --- the air cools it very rapidly.

While about 95C is an ideal temperature for water to hit the grounds, it's most unlikely to stay at that level through the 25" extraction.

-Robusto
,

That's why I like the ECM Giotto over the other prosumer E-61 based machines as it has a bigger boiler than most (all?) of them.

Yeah, the Faema is a good machine. But it is an old machine, which has been out of production for maybe 15 years. You can still get parts fro www.coffeeparts.com.au, such as element, boiler o-rings and group seals and thermostats, so short of cracking the boiler, the machine should be repairable.

I've done some preliminary thermologging and it seems that it is probably more stable than a Gaggia Classic, but shy of a Silvia. So for a sub-$300 machine, it is exceptional value, as long as you can keep it running.

As I mod the machine I'll keep you all updated as to what is possible with such machines.

Hi Sparky,

That's really great data and is very close to the profile I recorded (manually) for my Mokita. I didn't have the t/c bead inside the PF though, just jammed between the inside wall of the PF and the Basket, and I think this probably introduces an "averaging" effect where my measurements are concerned.

By the way, what do you use as a data logger for these recordings.... seems to be capable of quite respectable resolution? As always, great work Sparky and very valuable data for those of us with a temperature stability fetish. All the best,

Mal.

Hi Mal,

I use a cheap DMM, Digitech QM1538 with RS232 output. It's $60 from Jaycar. The high resolution was obtained by reading the RS232 output directly using a Matlab routine. The software that it ships with is not too good and it wouldn't work on my computer in any case (well not my laptop, but it worked on my desktop)... anyway, it records in 1 sec intervals. This is wierd as the DMM outputs at 0.4 sec intervals and there is no handshaking at all. So the software must either interpolate or it gets every second data point slightly wrong. So I wrote my own Matlab routine to read the RS232 output, giving me the full 0.4 sec resolution.

As for the PID controller, the autotune definitely wasn't on. These were 4 shots in succession (10-15 minutes between each) The last shot was a delay of maybe 30 minutes, which is amasing given it's closeness to the preceding shot. That's the sort of repeatability I'd like.

The rising temp is most likely due to elements in the brew path that don't passively heat very efficiently, so need a heating flush. This is very common with most machines and you really have to do some very careful engineering to avoid this (like the new La Marzocco home machine for instance). In the Faema's case, it's most likely the remote 3-way valve that needs to heat up with some flushes.

Hi Sparky,

Apart from the odd arrangement of the 3-Way Valve attachment, this looks to be quite a nicely engineered little machine. A pity they didn't stay with the original design instead of opting for an Al boiler and the Steam Slide Valve.

Will be very interesting to see what its performance is like after the PID installation

Mal.

Hi again Sparky,

Very impressive performance stats indeed for this little Faema.

The Wega operators must really know their machine back to front by the sounds of things, to be able to pull such good shots so consistently.... a bit of a rarity too I would imagine. It would have to be an easier proposition to practice on a properly tweaked commercial machine when someone else or the business is paying for the coffee consumption.

I guess we've all done our share of adjust grind, adjust dose, ensure tamp is level and then measure tamping force, pull the shot, taste the result.... and then start all over again. It can take quite a number of shots and adjustments to process variables before we get to the stage where an acceptable level of consistency of shot quality is achieved. I must admit that I find it a bit difficult to go through this sort of process when the end results are indistinguishable from shot to shot.... sure go through a lot of coffee until nirvana looks to be within reach.

Have you ever asked the barista(s) at work if they would let you pull a couple of shots on their Wega? Might be an interesting exercise just to see how your shots compare to theirs? If they can produce such good shots on a consistent basis, maybe a few lessons from their resident 'guru' is a possibility? You never know, and it might prove to be really worth while. Just a thought.....

Anyway Sparky, can't wait to see the results from the next phase of the Faema revamp. Will be very interesting to see how much of a difference the pre-heating boiler makes to the end result. Until then, all the best.....

Mal.

Sparky, I think this is but a small hiccup for a fellow of your talents...

I've got a couple of questions?

1. How do you reseal a "cracked" boiler...presumeably you need to insert a new element...how do you seal so you have no leaks under pressure?

2. Just what are the perishable parts in this machine as I'd like to be able to order a "kit" and replace them in mine.

cheers
xb

Hah ha!!!! Last night, amidst searing flashes of lightning and titaninc peals of thunder, the Kraema was born....

And it worked....  The boiler temperature went up when I hit the brew switch, not down.... Some tweakiing is needed, but I now have extra control over the boiler temperature during the shot.....

Damn right - propper moody night Dr Sparkenstein!

A postcard from flatland.




Still in testing phase, that's why the temp is low. I'll move the PID setpoint up this week to a proper brewing temp.

Using the simupuck, I took the machine for a spin. It's pretty well characterised now and a few interesting things came up. The brew water is totally decoupled from the feed water, even without preheating. This means the stable boiler temp can translate into stable brew temp. After a few hours of investigation I settled on a target brew temperature of 93 deg C and put in some real coffee and let loose. I did happen to log the shot, as well as taste it. Unfortunately the shot was too fast and the temp rose by about 0.5 deg C. And the taste.... well ... I think I need to use a better grind.

I have a mod in the pipe that should fix that rising temp that I get for doubles. A true ristretto would have been much flatter, and may have even tasted better...


Note, the coloured bar is 1 deg C thick

Well done Mark.

Regardz,
first crack.

Hmmm, upped the pressure from 4 bar to 9.5 bar.....  

Sparky wrote on Nov 12^th, 2005, 1:07pm:


very interested in this software you wrote please can i get a copy...

another post from faemageek a green bean,

When is the next coffee snobs event in sydney?

Cheers mate, will give that a go and if I fail with that then head to the professionals.  I have a contact at coffee works express in south sydney that should do the trick.  Thanks for your time.

Matt

Quote:


I'm sitting in an airport, so this will be quick for now. The output is in 0.4 sec intervals and consists of 14 byes. Each pair of bytes encodes either a digit on the display or some of the other indicators.  The code can be found by searching the jaycar web site in the forums. Just search for QM1538 and you should find it. Otherwise PM me your email and I'll send the details of the format.

Cheers,

Mark.

I'll be updating this project very shortly. I've just installed another mod that may well produce some interesting insight into this and similar machines. But then again it might not. We'll just have to wait and see. The latest mod is a first step to where I ultimately want to take it. Unfortunately taking it further might get expensive, unless fleabay can toss me some more goodies. For example the latest bit has a RRP of over $400, but I landed it for less than $50 (new).

The machine now only bares a vague resemblance to its former self. It looks more like some wierd Dr Who monster now. I'm still holding out to one day get a decent espresso from it though.

OK, the new mod is working and I have given the machine an initial spin.

I've just attached a pressure transducer to the steam pipe using a compression T fitting. I had a little trouble with the compression seals, so a bit of silver solder was employed. The result is a pressure tight addition that gives me an electronic pressure readout. The pressure transducer is the expensive bit. The cheapest one I could find here in oz was over $300. The one I sourced is much higher quality, rated for operation up to 125 deg C with an accuracy of less than 1% with linearity, hysteresis and bidirectional repeatability of 0.05%. I got a 60 bar unit. I would have preferred a 20 bar unit, but beggars can't be choosers.

This gives me the opportunity to do painless pressure logging while making a shot. I've never seen anyone submit a pressure profile to the various forums before (apart from a recent thread in home-barista where a pressure trnasducer was attached to a portafilter to monitor the pressure ramp up for three different machines), so this is an opportunity to test some commonly held beliefs.

My main motivation is to be able to use this sensor  as a means of controlling the brew pressure. That's the long term plan. I also have a shorter term plan to develop a simple electronic preinfusion control box for use with vibe pumps. This transducer will help me test the unit.

So to start off, there has been numerous discussions of the merits of the two main types of pump used in coffee machines. The vibratory pump used in small home machines and the rotary pump found in commercial plumbed machines. The rotary pumps have a huge capacity compared to vibe pumps and with the addition of a by-pass valve, can provide a stable brew pressure for multiple groups. In contrast the simple vibe pump is operating right near its capacity for just a single group. I'm always a bit nervous when a piece of equipment is operated near the extremes of its performance specs. So now to test it...  (caveat: As I don't have a rotary pump, I am unable to compare the two at this moment).

The first set of curves show the repeatability of the stalled pressure obtained for a particular setting of the OPV (Over Pressure Valve). I am using a Fluid-o-tech 70 W vibe pump with Fluid-o-tech OPV attached to the front of the pump.



Not too shabby. It hits the target pressure with a precision of less than 0.1 bar.

Next to compare the brew pressure to the stalled pressure (obtained using a blank filter basket)



Hmm, in this machine the pressure buildup is still quite rapid, taking about 3 sec with the blank filter basket and about 4 sec with a real shot (double basket).

Now let's have a closer look at the stalled vs brew pressure:



You can see that there is a 0.3 bar drop in pressure when actually brewing a shot. That is probably due to the fact that the OPV is right next to the pump, while the transducer is attached to the boiler with an intervening thermoblock in the way. So that drop is due to the resistence of the brew path at a brewing flow rate. Note, that there are no gicleurs or flow jets in this machine, so the two pressures are pretty close together. You can also see that as the shot progresses, the pressure drops. This was my best shot and it still drops. Others dropped by up to 0.4 bar during the shot. Some of it is due, no doubt, to channelling, but otherwise, its probably a natural effect of extracting the coffee oils, which progressively reduces the resistence of the puck.

One of the things I will take away from this is that the brew pressure won't be fixed. For a double, which has twice the flow rate, the drop in pressure should be greater again. I'll test this some time later. Also, for doubles, the vibe pump is operating close to its limit where the OPV can no longer regulate the brew pressure. So things might conceivably be worse still.

At the end of the day, I'm having a bit of fun with the machine and trying to learn a bit in the process. I'm still not drinking the espresso from this machine. I tasted it last night, but found it rather sour, so it's a temperature adjustment as well. But I used beans that always seem to produce a sourish taste from any machine I've used (at least 4 others including HX machines). They make great cappa's but not good espresso. So I'll go looking for a good espresso blend to try out now the machine is working and the pressure dialled.

Regards,

Mark.

Hi Sparky,

I read through your Faema Family thread with some interest. I picked up one of these nearly a year ago with the Faema grinder to boot for the grand sum of $135. MIne is white with a black and white two tone grinder ! I had to replace the group head seal but apart from that everything was operational. Now the element has started to trip out the circuit breakers (so probably a good run for something that is 17 years old. I have one of these one order as well some new seals.

Since I have the thing stripped down I have though about PIDing it. Did you manage to fit this internally? Its a pretty homely machine anyhow so a black box hanging on th side wont improve things. What I can gather you also took out the boiler tube ? Is that still out and something you would recommend doing ? And finally I noticed on your picture of the three way valve the 'free' tube has been tied off. Mine isn't and I can say the three way effect only works sometimes - wet grounds on many occasions. Any thoughts ?

Thanks in advance for any advice you can spare,

Rick

Here's a photo-update of the machine and a shot using the naked PF.

The ugly-duckling itself... Not really ready to go out in public, but working nonetheless.


What's lurking behind? A thermoblock and a new pump/OPV. Note: the SSR will be moved.



And last the pressure transducer T'ed into the steam line and insulated boiler.



And here's what come out the business end. This one was pretty thick. Brew temp was too hot though.



What's good about this setup is that the machine is no longer a major factor in determining what goes in the cup. It brews at 9 bar (easily adjustable) and the temp can easily be set with 0.5 C precision. That leaves the hard stuff: Grind, dose and tamp. Still enough to keep me busy.

Cheers,

Mark.