Hey Folks -- long time reader, first time (apparently) poster. Looking back at my email I can see that I "registered" this username in 2018, 2019, 2021, but apparently I never "confirmed" my email address any of those times. Sheesh, what a loser. Anyway, on to the question...

I've got a circa '95 Unic Diva (single group, 115v) that has been in the family since around 2001 or so. It's a workhorse and we use it every day. In the spring of 2020, the group head started leaking. I determined the problem was a weak (flanged) 3-way group head solenoid valve. I had trouble getting a response from vendors about a replacement part early in the pandemic, so after trying to dissemble/clean, I swapped in the (ruby) nucleus from my spare machine (pro tip: vintage machines benefit from a spare "parts" machine). That resolved my issue and kept us caffeinated and sane during Covid. I made a mental note to procure another when the supply chains were better. Three years later, it's dripping again and whoops, it turns out a) I never got that part, and b) the "exact" version is less available than it was three years ago.

I again disassembled/cleaned the valve body to see if that would fix things. It looked good. No scale, no grit -- our water here is super soft -- so I stretched the spring a tad and reassembled. It worked for a couple shots, then started dripping again, which tells me the nucleus in this one is bad (again).

All that is a pretty long-winded way of asking if anyone has insight on the parts interchange possibilities for a 115v, flanged, 3-way solenoid valve. The current solenoid is an ODE with a ruby nucleus. Coil is marked:
31A1A5R11-V.

Other markings are 19 Bar AC, DN 1,1mm (orifice size, I think), W 8,0 (8 watt?) ED 100 % (I have no idea what this is). I believe the drain port is 1/8th bsp (I measure it at 9.4mm) with my crappy calipers), and the flange base is 32.4mm dia. I can find a few ODE solenoids online, but they all seem to be 230V.

additional angles.


I found an ODE replacement nucleus, but it's has viton vs ruby seals. I feel like read somewhere that the viton is not the right choice here, but I can't find that reference. Plus, I'm feeling replacing the entire unit might be a better move at this point. So....

Am I stuck finding an 110/115V ODE or will any 110/115v, 3-way, (at least 8 watt with correct discharge threading and flange diameter) work? And if so, is there anything wrong with going with the ubiquitous Parker ZB09 3-way? It seems the most available, and often available for around $50 if I'm willing to wait a bit. But that said, other brands such as Sirai, Asco, Lucifer, and so on also seem to make a 3-way that meets the specs. I'm happy to pay a little more for higher quality to keep this machine trucking along another 20 years.

Thanks everyone!

JRising wrote:I prefer the ruby over viton on brew valves because they inherently keep themselves cleaner. But your opinion is up to you.
I don't know anything about Unic Diva, but I'll assume that the valve in question is being used as a brew valve or it wouldn't need to be a quality valve, so "yes" if its an identical valve as far as orifice and voltage, then the Parker one from EspressoParts that you linked to seems like a good choice.

Thanks much. Yes, brew valve. I called it the "group head valve", but I guess that's the wrong term. And thanks for the thoughts on Viton vs. Ruby. It seemed like sticking with ruby was good ideal so thanks for the points about it being easier to keep clean. That Parker valve is ruby so that's another point it its favor.

JRising wrote:They, right there on the page with the valve encourage:
If you have any questions or need assistance we have an awesome customer support team that would love to help you! Please call us! 1-800-459-5594 or email info@espressoparts.com

If you're planning on giving them your money, and you think that they might know the answer, you could ask them instead of reposting here. If they become responsible for the valve in your machine, then they'll want to make sure you get an appropriate one.

That's a good point. However I've also found having a funky French espresso machine means a lot of vendors won't help because it's not on their "list" or in in their experience wheelhouse. I contacted Espresso Parts years ago about an expansion valve and water supply lines/fittings and they basically shrugged. So that's why I thought I'd reach out here, hoping someone had generic experience with whether the valves are interchangeable so I'd at least have some idea if I was looking in the right direction before I jumped in with a vendor.

Maybe the lesson I need to learn here is that I don't always need to mention the Unic-ness and can just ask a generic question like: "how interchangeable are brew-head 3-way solenoids."

Thanks again!

Another choice you might have is whether the solenoid base is brass or stainless steel. Some manufacturers are moving completely away from any brass content in their machines.

That's a good point. This machine is pretty much all brass and copper, all the way down to the giant 6.3L boiler so I may as well stick with it. The flange for the existing valve is brass, which matches the Parker one linked above.

Thanks!

Viton are suggested for cold water (entry valves)
rubin for 3 way (or brewing valves)

Aha, so that's the difference. Thank you!

AFAIK KvdW is still using Viton in their 3-way brew valves.

Just an update. I ordered a Lucifer (well, Parker since they've apparently bought everything) brew valve from Stefano/Espresso Care and got it installed; machine is back up and running! I thought I'd mention a couple issues I had that may help future newbies (or old newbies like me when I have to replace this again in 2033.

1) If you haven't worked on your vintage machine for a few years, don't trust your memory.
2) ODE (the Unic oem) solenoids are weird and have their ground terminals on the "bottom" (closest to flange) vs everyone else who seems to put them on the "top" (near the outlet). This kind of freaked me out because I thought I'd have cut/splice wires to make the harness plug fit the new solenoid and I didn't want to cut into a 30-year old harness.
3) It turns out that "weirdness" is no biggie. On most machines, the terminal plug "case" can usually be taken apart and contacts twisted 180 degrees to orient the plug in the correct direction. No cutting/splicing/soldering/crimping required. I should have know this (without the mini freakout... sorry Stefano), since I've actually taken apart/replaced these plugs before. I even sharpied on the inside of the plug where the various wires went. But I forgot all of that as the years have passed (see point 1, above).
4) When modifying the plug, remember the ground position matters (must connect to ground, duh) but the other two wires can connect to either side of the solenoid terminals.
5) Right after I got everything back together I wished I had replaced the plug (I had a new one on hand and the case was a little cracked) and the group gasket. I should have planned some maintenance while it was down. Next time, I guess.

Thanks everyone for the help!