E61 drain valve not working...

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
daviddecristoforo

#1: Post by daviddecristoforo »

New member, first post. My machine is a 2000 vintage LaScalla Butterfly. It has been modified over the years with a rotary pump, shot timer, Quickmill "joystick" wands, etc. Recently it had a new "brain box" and pstat installed along with all new valves.

Over the weekend I rebuilt my E61group head. It was loaded with crud and scale and the seals were in very bad shape. After cleaning and descaling, all new valves, seals and gaskets were installed. Everything seems to be working properly except the bottom pressure relief/drain valve is not working. I also installed a Coffee Sensor flow control. I don't know if the stronger preinfusion spring would affect the relief valve or not. I thought everything was installed correctly but obviously something is causing the pressure relief valve to stay closed when the group lever is returned to the lower (off) position. If anyone has any ideas about this, please let me know.
Thanx...
DD

richiekess
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#2: Post by richiekess »

This is a good guide to follow for an E61 rebuild.

http://www.espressomyespresso.com/HowToE61overhaul.html

I had that happen to me on some rebuilds that I have done. The exhaust wouldn't work. I swore that I assembled the new parts correctly but inevitably I made a mistake with either a spring, valve, or the direction of the valve. Some of the small valves that do in the exhaust chamber look similar in size but are not in shape.

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daviddecristoforo (original poster)

#3: Post by daviddecristoforo (original poster) »

That's the exact tutorial I used as a guide! Maybe I'll just have to take it apart again (ugg!) One thing I found is that someone said that you should reassemble the cam section first but this tutorial has it last(!?)

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Randy G.

#4: Post by Randy G. »

When the cam is in the "neutral" position there should be a bit of freeplay in the lever and so even with the entire group assembled it should be easy to insert the cam assembly. If for some reason there is no freeplay in your group in that position, just loosen the bottom portion and that should create enough play. You just want to be sure that you hand tighten the cam housing to be sure that the cam is between the brew and infusion shafts in the chamber. If you look at my HOW-TO 18 - Simple Lubrication of the E-61 Group you will see that you can I "prove" that the cam assembly can be removed and replaced with the rest of the group intact. I suppose that in some designs there could be exceptions, but in the ten years those two "How To" pages have been online I have never had any other statement that it could not be done.
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daviddecristoforo (original poster)

#5: Post by daviddecristoforo (original poster) »

Well I proved it too because I followed your instructions to the letter. But my exhaust valve still doesn't work and I have to wait for the pressure to disperse through the puck before removing the portafilter. I will try what you suggest and post back.
PS Thanx for the tutorial!

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Randy G.

#6: Post by Randy G. »

I was speaking of the ability to remove and replace the lever/cam assembly

In terms of the 3-way not working, if the 3way was releasing pressure before the disassembly then it should be now. For more info on how the E-61 works, consult the Vibiemme Domobar Double owners manual, (PDF download) pages 5 through 8. (DISCLAIMER: I created the manual but the download is free, hosted on Stefano's website, Espressocare.com). The diagrams and explanation in the manual may assist in diagnosing the problem. I do not claim universal knowledge of the details of the inner workings of all the E-61 designs, but the basics of the manual group are all the same as far as I know. If the lever moves through its normal range, and when fully lowered in the "off" position, the 3-way should be opened.

If you received entirely new valve bodies for inside the group, then it could be that either or both of the lower valve assemblies is wrong for your machine. When the lever is lowered, the cam presses on the infusion valve, and that valve then pushes on the 'exhaust' or 3-way valve which can then release the pressure. If the infusion valve does not move a sufficient distance then it cannot open the exhaust valve. If the exhaust valve is, for example, too short for the infusion valve to push on it then that will also cause the valve to not open.

So, the tl (too late), but tldr is, if it worked with the old valves then it should work with the new ones, UNLESS they are the incorrect length, or were installed incorrectly, etc. If we assume you installed all the parts correctly then it is time to take out a dial caliper and measure the length of the old parts against the new ones.
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daviddecristoforo (original poster)

#7: Post by daviddecristoforo (original poster) »

This sounds logical. I'll check the valve lengths this evening when I get home. I could always put the new seals in the old valves if necessary...no?

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JRising

#8: Post by JRising »

daviddecristoforo wrote:That's the exact tutorial I used as a guide! Maybe I'll just have to take it apart again (ugg!) One thing I found is that someone said that you should reassemble the cam section first but this tutorial has it last(!?)
Cam section FIRST definitely.
Otherwise, one of the valves will be in the way and make it hard to put the cam in.

Test it without the drain valve in place. With just the preinfuse and its new spring in, the drain valve, its spring and the lowest section of the valve housing removed, does the preinfuse valve function as a drain valve? If so, hold the drain valve in place up against its seat at the bottom of the preinfuse valve and raise and lower the lever, can you feel the preinfuse valve opening and closing the drain valve?
If even the preinfuse valve isn't moving, did you get one too many teflon gaskets at the top and it's holding the entire valve housing too low?

This should help you figure out which valve isn't being opened.

daviddecristoforo (original poster)

#9: Post by daviddecristoforo (original poster) »

So I took it apart again and compared the old valves with the new and they appear to be identical. Right now the whole thing is wonky but it still doesn't depressurize properly. I'm going to wait until the weekend and then tear the whole thing down again and start over. One thing I'm realizing is that there are different versions of this group head. It's not like an E61 is an E61, period.

By way of additional information... now when I open the brew valve (lever in the up position, water starts flowing from the drain valve. This continues for several seconds after the lever is moved to the closed position (lever all the way down). It continues to flow throughout the whole shot time. I have a gauge on the group head that indicates 8 bars during brewing.

I'm baffled!

daviddecristoforo (original poster)

#10: Post by daviddecristoforo (original poster) »

So I finally got this working but I'm still a bit puzzled. When I first took it apart there was a rubber washer, similar to the ones on the cam shaft, at the bottom of the preinfusion chamber. I thought it odd at the time because the rebuild kit only had two, not three. The washer seemed to be in ok shape so I just turned it over and put it back in.

But today, after spending hours taking the thing apart and putting it back together again and swapping parts in and out, I realized that not one of the diagrams or photos or tutorials I have seen show or mention that rubber washer. The light went on as I realized that it didn't belong there. I dismantled the lower chamber again, removed the washer and put it back together. Ran the pump against a back flush basket, then moved the lever to the "off" position and there was that satisfying "pffff" sound if the pressure being released.

So now that it's working properly, I'm wondering why that washer was in there in the first place and why it ever worked at all with it in there?!?! The group head has never been taken apart up till now. I bought the machine new and only took this rebuild on because the drain valve would not stop dripping.

Anyone have any idea about this? I'm glad I got it working again but I'm still puzzled...