I am starting to do my initial adjustments on my 'New' Rancilio S27. So boiler pressure is the first place I am starting. I will get to that, but a bit of story first...

I picked her up in Southern California for a great price. She has been dead for at least 4-5 years, her boiler would come on, but her brains where fried, her Procon pump was frozen up solid, and her body had leaves scattered inside.

I knew all of this when I picked her up on the 9th, what I didn't know was if I was up to the rebuild. You see, I have never owned an espresso machine before. My biggest worry was the main CPU, if I could not get that running the rest of the project would be a zombie at best.

I got her home and pulled of her panels, as I mentioned there were leaves and for a bonus, a family of spiders. Once the flora and fauna were dealt with I removed the main controller board. It seems at some time that the auto fill sensor had gotten so dirty that the boiler overfilled and sent water everywhere inside. The CPU board had water spots and minor corrosion all over, maybe the person got lucky and when the controller shorted out and died the pump would have shut down and saved them from a nasty flood.

Thankfully this was 80's tech and was quite simple to clean up and diagnose where the damage on the board was. So off to e-bay I went to order a new chip. A quick transaction later and the IC for the repair was on it's way. This left me to deal with the dirty work.

To make this shorter lets say everything was torn down to the bare frame and descaled. The Procon went off to be refurbished. Two pounds of citric acid later and the boiler/pluming/valves are all back to great condition. One UPS delivery, a trip to my electronics shop for a socket, and a bit of electronic voodoo and the main controller was alive again. Which left me where I was yesterday, with a pumpless machine. But my friend Mario from Espresso Tec lent me spare Procon last night. (Thanks!)

I got back to the apartment, bolted the pump up to the motor and ran in the feed and pressure lines. I haven't had time to plumb anything in so I fed her from a gallon jug and placed a 1/2 sheet tray under the drain line spout.

I flipped the main power on and my baby had her new first birthday. The Procon pulled in about 2L of water to fill the boiler (the boiler is actually 3.9L) and the element had the water boiling and the vacuum breaker sealed in a bit over 5 minutes. Not bad from dead cold, my little electric water pot is slower than that.

When I tore everything down that included the Sirai pressurestat. I was not sure the membrane would be good still. It was fine, and there was only some minor corrosion in the brass membrane holding shell which was easily descaled. (As an aside I did end up filing the points down so they were not all gunked up. Thanks all.) Since I was unsure of the boiler seals after tearing everything down I dialed the loading spring on the pressurestat all the way down. As it turns out this model kicks the boiler off at .5 bar when set to it's lowest pressure setting.

After assuring myself that everything was holding I started dialing up the pressure. I did take it as high as 1.5 bar just because 'I don't know if she can take this much longer Jim', with no nasty surprises. I have dialed it back down to .9 bar now. I seem to have about .2 bar of float in the Sirai. So the element will kick in at about .8 on the gauge, and will turn itself off at 1.0 bar. This is much narrower a range than say the presurestat on my well. Is that an acceptable dead band for a pressurestat on an espresso machine? The math in my head says this is about a 6-8 degF swing.

I did pull out a 20oz pitcher to see what the steam power will be like. Let's just say no problemo there. I had maybe 9-10 oz of milk straight from the refrigerator and it was up to 150deg F in less than 20 seconds. Started tip submerged, opened the steam valve, tried to chase the milk level up and at this point the thermometer was already reading 100. I plunged the tip back down, checked the thermometer again 137! I cut the steam off as quick as I could, and as the last of the steam sighed off the thermometer coasted to 155. Not the best micro foam I have seen, but a couple knocks and a swirl or two and there were no dishwater bubbles. Holy heck is this fast.

Now to wander back onto the subject...

So no steam worries, so lets talk temperature. More specifically lets talk what temperature we want to worry about as well as a cheap and easy way to measure it. (Glances worriedly in Mr. Scase's direction.) If I just flush water through the group it's temperature will be off high in the beginning, and off low at the end. But will it give me a decent average reading? Will that reading have any useful meaning?

Or should I even be worried about temperature at this point and just let the machine do what it does at .9 bar?

-Cecil

CRCasey wrote:<snip> <snip> <snip>...

If I just flush water through the group it's temperature will be off high in the beginning, and off low at the end. But will it give me a decent average reading? Will that reading have any useful meaning?

See Seeking low tech way to measure brew temperature and the famous cheap but good enough Styrofoam/thermometer technique. That's what I used for years prior to the introduction of the thermofilter. It helps to have a cribsheet of the brew temperature management regime for your specific machine; here are some general tips:

• Commercial espresso machines typically don't have the huge flushes you'll read about for prosumer/semi-commercial units. Flush until the end of the flash plus a few seconds, lock in, pull without delay.
• Some commercial espresso machines have significant "thermal memory". That's a good thing if your boiler pressure setting is correct and you don't make the mistake of overflushing. It's a bad thing if you screw up, since it will take awhile to reset the overall group temperature before retesting. Example: La Cimbali Cimbali Junior. Counterexample: Elektra A3.
• To get a quick grasp on your machine's natural steady state, try drawing water until the flashing stops plus a few seconds, pause for a moment, then measure into the Styrofoam cup/thermometer. Record the reading. Repeat this at 3 minute intervals 5 times. Practically all HX espresso machines will fall into a natural groove by the third or fourth time; adjust the flush amount up/down as needed.
• The "flush and go" technique invariably works better with commercial espresso machines. If you flush and wait 15-20 seconds as you can with some prosumer/semi-commercial units, the brew temperature will be way too hot. Commercial espresso machines like to be run flat out.

If you haven't already done so, read How I Stopped Worrying and Learned to Love HXs. It explains all the necessary background information to make sense out of the above.

Thanks Dan,

I have read Learned to <3 HX's through a couple of times. It just didn't seem to fit with what I was seeing with this larger HX/Boiler on the S27. I will do a bit of profiling and check out what the cup and dipstick can tell me.

-Cecil

How about some pictures too!!!!

Mark

I have not finished cleaning the pretty outer bits yet. So she is sitting bare naked on the counter with her frame showing. I have to run up to Denver for a couple of days, but I will take a shot and post it when I get back.

-Cecil

CRCasey wrote:Or should I even be worried about temperature at this point and just let the machine do what it does at .9 bar?

Cecil, from experience, if your S27 is anything like my S26, it has a hanging group head with no thermosiphon and it's anything but temp stable! It's a challenge and, IMHO, most of the techniques out there don't apply to this monster. Welcome to the club!

To create a not-so-bad brew temp line, you'll need to develop a routine that gets the GH hot enough and the HX temp cool enough at the same time. I'd suggest you have a stable machine before exploring said routines; since, from experience , many things affect this monster's brew temp, including shot flow rate, basket headspace, to name some.

Good luck!

Hi Max,

The S26 and the S27 share the same internals except for the CPU/Keypad and the flow sensor. The boilers, HX, and head configuration are the same. Thanks for the welcome!

I will not be back home to work with this until Friday. I am planning on getting a baseline feel for the overall temperature profile/drain/surf with Dan's suggested styrofoam cup method. But if you have a favorite routine that you use I will be more than grateful for a quick write up.

-Cecil

Here is the picture I promised, she is on the counter bare until I clean up some of the panels. As you may notice I only have the control panel slid into place, it has not been cleaned up yet either.



I have the parts for a pressure gauge, so I will put up a set of pictures as I build it and dial in the pressure and flow.

-Cecil

Here is an exploded view of the parts I have for my brew pressure gauge.



-Cecil

And here is the assembled gauge attached to the portafilter waiting for me to dial in the needle valve flow.



-Cecil