Pressure Modification on the Eliane and Silvia

[russell]

I'm going to start this topic by attempting to send a photo I took today of a special wrench I made for adjusting the OPV on the Eliane (similar to the Zaffiro or Amica). The purpose of the wrench is to made the adjustment without taking the machine apart; in fact, it's easy to adjust the pressure during an actual brew. If this photo goes through, I continue the thread with other photos and descriptions of mods to the Eliane and Silvia. So here's the picture (hope I understood Dan right):



Assuming the photo goes through, you'll see a PF with a pressure gauge (about $35 from Espresso Parts NW) and the wrench. The gauge was mainly used for the Silvia which, of course, lacks a gauge, but I also used it to confirm the pressures recorded by the gauge on the Eliane.

The tool was made from an inexpensive 10 mm bicycle wrench and a flat piece of brass purchased at a True Value hardware store. The end of the bike wrench was cut off to make an open-end wrench and the wrench head was bent 90 degrees. (the wrench on the other end was cut off.) Holes were drilled in the body of the wrench and the brass rod and the two were bolted together to form a tool with about a 10" total length. With it I can reach down from the top and turn the hex nut on the OPV to regulate the pressure.

If this goes through, I explain this further in the next post on this topic.

Russell
P.S. Looks good on the preview!

[russell]

Looks like the photo went through, so here's rest of the story.

In my brief study of espresso and machine modifications, I found that it's almost universally agreed that the ideal brew pressure in under 10 bar (typically 9 bar is recommended). The gauge on the Eliane was registering about 15 bar during brewing when tried out of the box. I removed the housing, located the OPV and experimented with turning the nut in each direction when running the machine with a blind filter. The best I could get was 11-12 bar with the fitting backed way out until it was loose. Beyond that, the fitting leaked. I removed the spring inside and filed off about 0.5 mm and reassembled the OPV. I could now adjust to 9 bar by backing off on the nut. I also discovered that (at least on this machine) 9 bar with a blind filter only equated to 8.5 bar with brew going on. Apparently the water passing through the PF during brewing alters the system so that the OPV spring does not move to exactly the same position during brew as during a total stoppage (when using the blind filter). So I adjusted back up to almost 10 bar.

I then decided I wanted to be able to make this adjustment anytime. (In fact this proved worthwhile because several weeks later the max pressure seems a little lower so I made another adjustment.) That's why I made the wrench shown in the last posting. I also cut away half of the top of the inner cover (the piece that goes under the water tank, up its inner side and covers the boiler and wiring. This opening, shown in the photo, forms an access panel for adjusting the OPV and checking the wiring. It is covered by a top plate so the wiring is not really exposed. (An access cover like this has been discussed in earlier posting on the Eliane.) Here's the picture:



The cork shown in the water tank at the bottom is part of a crude water gauge: a short piece of thin down was pushed into the cork and a piece of flexible plastic tubing then pushed over the down, As the water level drops the cork goes down pulling adding tubing below the level of the top of the machine. A black mark on the tube indicates when the tank is low. I used a tube because the machine fits under a kitchen cabinet and a rigid rod (like a dowel) wouldn't fit. Crude, but it works.

In the next photo, you can see the brass OPV (barely) looking down from the top (I removed this inner cover, but not the whole housing for this picture.) Its at the bottom of the plastic tube running down the middle of the picture, just to the left of the yellow wire. You can also see the insulation around the boiler (the temp probe is under a hose clamp under the green insulation; the insulation on the copper pipe is just there to protect the wiring). And you can see the SSR (relay) that is controlled by the PID on the extreme left under the old (disconnected) thermostat.
(I'll describe the PID in a later post.) Here's the photo:



In the next post I'll describe the Silvia pressure modification.

Russell

[russell]

OK, now for the Silvia pressure modification. This proved much more difficult. The recommendation found linked on this site was to purchase a second brass washer and add it to the system to reduce pressure. But I read a post that said when this was attempted the pressure went way low. And the part seems to be hard to find. On my machine, at least, the fitting was angled way down and was a real bear to remove. It was on really, really tight and I was worried about breaking something. However, supporting the fitting as the nut was turned (with a big wrench) finally did the job. Unlike the Eliane OPV, this one is not adjustable. Backing out on the nut almost immediately produced leaking.

The solution was to purchase some fiber gasket material and cut out a washer. You can see in the photo that the outside is preety crude (an octagon, I didn't bother to round it. Surprisingly, even though the gasket is much thicker than the original copper washer, I still couldn't get the pressure down to 10. So I took the spring out and filled it down like I did with the spring on the Eliane OPV. And even then I had to add the original copper washer back into the system. I also put two winding of teflon tape on the threads to minimize the chance of leaking. With this set up I was able to adjust the pressure up and down without any leaking, and make dynamic adjustments while the PF with the gauge (shown in the first posting on this topic) was in place. I set the pressure at 9.75 bar on the assumption that the actual brew pressure would be a little less as it was on the Eliane. Of course, without a built in gauge I couldn't test that, but the coffee tastes great!! Here are two photos that show the pressure mod:





In the first you can easily see both the homemade fiber washer and the original copper washer. In the second, you can also see the SSR (relay) mounted on the side wall. (I'll discuss the PID in another posting).

One other suggestion, learned after wasting time: don't remove the hose clamp and plastic hose from the pressure release fitting as recommended in the earlier link. It's a pain to get back on, at least on my machine with the fitting angled way down. Instead, remove the other end from the water tank, push it back into the boiler chamber, and just untwist it as you unscrew the fitting or put the fitting back on. When you're down just push it back through the side opening and up and over into the water tank again.

The pressure mods on both machines are inexpensive and non-technical. The only real cost (for the Silvia) is the PF with gauge, and I suppose one can be borrowed if the $35 hurts too much. By making these mods, an important variable is controlled and one potential strike against the Silvia is removed. The tool for adjusting pressure on the Eliane was really overkill--it's not so hard to remove the cover and make the adjustment. In the case of the Silvia, once teflon tape is applied to the threads and moderately compressible gasket material is used, the adjustment is easy through the open top (only 4 screws).

I'll post photos of the PID modifications tomorrow or later in the week.

Russell

P.S. I hope this all isn't too much. One reason Im doing it rather than just providing written descriptions is that someone over on Coffee Geek questioned my "veracity" which I interpret as an oblique way of saying I'm lying about my tests and mods. I own three machines, a Silvia, an Eliane, and a Solis SL-90 and I've spent considerable time and money modifying both the Silvia and the Eliane. I want to see if I can get results out of the Silvia which (to my uneducated taste) are comparable to those from the Eliane. Then I can sell the modified Eliane and keep that nice unassuming Silvia with a good conscience. But if I can't get comparable results, the Silvia goes.

[hakkr]

Thanks for posting your modding notes and pics. The hose clamp on my
Silvia is a bitch to remove as well, so I am glad there is an alternative.
I was in fact wondering if it will be okay to test unscrewing the fitting
a little without first worrying about unscrewing the hose from either end

Actually, right now the bigger problem I have is that the hex nut is not
budging no matter what I try. I have already returned a set of vise
grip / adjustable wrench because they are too short and don't provide
enough leverage. Will try out with some beefier tools to see if I can
unscrew the nut. Someone in another forum suggested wiping some
WB40 around the nut/gasket, but that is a little too yucky for me.

First time I am reading the use of a fiber gasket. Seems like a nice idea
as well. Any leaking issues so far? Also any chance little fiber thingies
will go into the water? I am a little paranoid that way.

Sam

[russell]

Hakkr, your problem in removing the fitting parallels mine. I can't believe how tight the fitting was on machine. I think I finally used a set of water-pump pliers with about 12" handles. Of course, you have to hold the other part as well. The fitting finally broke free. I have no idea if WD-40 or Liquid Wrench would help--I didn't see any sign of anything on the threads.
I think it is impossible for any fiber to get into the water. I don't know how much if any water works it way through the threads with the teflon tape to reach the gasket--my guess is none since I can adjust the nut in and out without leaking. Even if a minute amount of water reach the gasket, it is certain that no fiber material could work its way back through the threads and teflon tape to enter the resevoir via the hose from the fitting.
No, I have had absolutely no leaks and the pressure is holding steady at just under 10 bars with a blind filter.
Russell

[tom_b]

More nice geeking, Russell. Removing the tube for silvia isn't hard if the prongs on the wire squeeze clamp (the technical term, not) are pointing up, allowing free access with needlenose pliers. If pointing down, they can be rotated toward the front with a squeeze/twist movement, replete with flared nostrils, contorted posture and one foot in the air. IIRC it is easier to rotate it in the direction of the loop side of the prongs, with pressure on the two wire tips that come together to form the other prong.

Like the washer allowing a range of adjusment.

The sudden lunge of the wrench is pretty wild, yes? Haven't heard of any reports of the OPV breaking, but after the initial loosening there is that moment when you check - did I bust it..?
tom:)