ahains Senior Member Joined: 5 Feb 2004 Posts: 174 Location: Renton, WA Expertise: I love coffee
Espresso: FrancisFrancis X5 Grinder: Innova Conical Burr Drip: Gevalia (was free) Roaster: Hot air popper
Posted Wed Oct 6, 2004, 3:02pm Subject: Anyone ever retrofitted their espresso machine with a 3 way valve?
My FF! X5 does not have one, so it is annoying to get the coffee grounds out of the basket after I pull a shot. I also have to watch out for the espresso sneeze.
I think it may be somewhat costly to actually find a good 3 way valve I could pop in there, but I was considering simply adding an additional 2 way valve. This would tee into the line that goes to the group head, and would be operated seperately. So I would pull a shot like normal, then turn off the pump like normal, and then hit my additional button to release pressure in the line & group head to a line that routes back to a waste container. Sounds simple enough.. Most of the inexpensive 2 way solenoid valves ($20-$30) can only open with like 100psi pressure differential, but I think it would be less than this almost immediately, since grounds are letting pressure out continually.
Thoughts? Thanks, Adrian
"What's the matter with this thing? What's all that churning and bubbling? You call that a radar screen?" "No, sir. We call it, "Mr. Coffee." Care for some?" "Yes! I always have coffee when I watch radar. You know that."
ahains Senior Member Joined: 5 Feb 2004 Posts: 174 Location: Renton, WA Expertise: I love coffee
Espresso: FrancisFrancis X5 Grinder: Innova Conical Burr Drip: Gevalia (was free) Roaster: Hot air popper
Posted Thu Oct 7, 2004, 6:16am Subject: Re: Anyone ever retrofitted their espresso machine with a 3 way valve?
Thinking of the current behavior of my espresso machine, it must actually not have any solenoid valve at all. After you pull a shot, it still drips water for quite awhile..
It can handle 200*F, 250psi, runs on normal AC voltage, and costs $35. It is normally closed, which is good. I just want to be able to give it a second or two of voltage to have it dump pressure. I could also plumb in a 38105K34 pressure gauge (~$8) to verify I'm under or around 150psi when I want to hit the solenoid valve.
I would prefer to use 7877K53, since it is only $18, but I think the 120*F limit may prove to be an issue. Tough to say since it would only be letting out brief bursts of high temp water/steam.
I may add this to the list of things I'll probably never get around to trying. I'll post back if I ever do try it :) -Adrian
"What's the matter with this thing? What's all that churning and bubbling? You call that a radar screen?" "No, sir. We call it, "Mr. Coffee." Care for some?" "Yes! I always have coffee when I watch radar. You know that."
Posted Thu Oct 7, 2004, 12:45pm Subject: Re: Anyone ever retrofitted their espresso machine with a 3 way valve?
More power to you ...I had been contemplating doing this to my previous machine before I sold it but it had other problems and was not worth the trouble.
ahains Said:
It looks to me that this might be the best solution: http://www.mcmaster.com/asp/enter.asp?pagenum=395 See part number 7876K11. It can handle 200*F, 250psi, runs on normal AC voltage, and costs $35.
Yes I agree that this looks like it would fit the spec.
ahains Said:
I would prefer to use 7877K53, since it is only $18, but I think the 120*F limit may prove to be an issue. Tough to say since it would only be letting out brief bursts of high temp water/steam.
Yes this sounds like it would work also. If it's rated for 120degrees this would undoubtedly mean continuous 120degrees so I would expect it to be able to be able to handle brief bursts of 195degree water followed by the typical rest which would have to be at least about a minute even for a fast barista. Some other issues you may encounter:
Drilling the hole in the grouphead and tapping it for the fitting. It would probably be difficult to get it to come out at the right location.
Deciding on the diameter of the tubing from the grouphead to the valve. It seems that it shouldn't be too large because it would unduly increase the size of the pressure chamber; nor too small as it could become clogged with coffee grains.
Coffee grounds in the valve passageways might be more of an issue on some valves than on others simply because of variations in valve seat construction from one valve to the other.
Posted Thu Oct 7, 2004, 12:47pm Subject: Re: Anyone ever retrofitted their espresso machine with a 3 way valve?
More power to you ...I had been contemplating doing this to my previous machine before I sold it but it had other problems and was not worth the trouble.
ahains Said:
It looks to me that this might be the best solution: http://www.mcmaster.com/asp/enter.asp?pagenum=395 See part number 7876K11. It can handle 200*F, 250psi, runs on normal AC voltage, and costs $35.
Yes I agree that this looks like it would fit the spec.
ahains Said:
I would prefer to use 7877K53, since it is only $18, but I think the 120*F limit may prove to be an issue. Tough to say since it would only be letting out brief bursts of high temp water/steam.
Yes this sounds like it would work also. If it's rated for 120degrees this would undoubtedly mean continuous 120degrees so I would expect it to be able to be able to handle brief bursts of 195degree water followed by at least a minute of rest. Some other issues you may encounter:
Drilling the hole in the grouphead and tapping it for the fitting.
Deciding on the diameter of the tubing from the grouphead to the valve. It seems that it shouldn't be too large because it would unduly increase the size of the pressure chamber; nor too small as it could become clogged with coffee grains.
Coffee grounds in the valve passageways might be more of an issue on some valves than on others simply because of variations in valve seat construction from one valve to the other.
ahains Senior Member Joined: 5 Feb 2004 Posts: 174 Location: Renton, WA Expertise: I love coffee
Espresso: FrancisFrancis X5 Grinder: Innova Conical Burr Drip: Gevalia (was free) Roaster: Hot air popper
Posted Fri Oct 8, 2004, 7:24am Subject: Re: Anyone ever retrofitted their espresso machine with a 3 way valve?
Ah, I hadn't considered that coffee grounds may come out this direction. Very good point. My most recent thinking was that I could just T into the existing line, but I see now this may not work. Depends on the diameter of the tubing that is in there currently, which if I remember correctly, was fairly thin. I guess I'll just have to open her up again and take a look. It would be nice if I could T in, because I really don't want to drill into my grouphead if I can avoid it. That might be a deal breaker :) I would like to be able to return the machine to stock if need be.. FrancisFrancis! might look at me funny if I send the machine in for some warranty repair and they find a 3-way valve in there ;)
Thanks! Adrian
"What's the matter with this thing? What's all that churning and bubbling? You call that a radar screen?" "No, sir. We call it, "Mr. Coffee." Care for some?" "Yes! I always have coffee when I watch radar. You know that."
Posted Fri Oct 8, 2004, 1:31pm Subject: Re: Anyone ever retrofitted their espresso machine with a 3 way valve?
ahains Said:
My most recent thinking was that I could just T into the existing line, but I see now this may not work. Depends on the diameter of the tubing that is in there currently, which if I remember correctly, was fairly thin. I guess I'll just have to open her up again and take a look.
I'd doubt that the existing connection from the boiler to the grouphead is via a "line" or pipe. You may be confusing the hoses. All espresso machines have a need to get not just water from boiler to grouphead but heat also -lits of it and quickly. Otherwise they'd need a separate heater for the grouphead. On Gaggia, the Bottom of the boiler is an integral part with the grouphead itself - a very efficient way to transfer heat. On Silvia, the grouphead is slightly offset from the bottom of the boiler but it's big stocky metal throughout; not just a pipe, and again close to the boiler. I don't know what they do on FF's but it's probably something similar and you'd probably have to be drilling into stocky metal (brass or aluminum usually). You'd probably have to forget about your warranty.
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