Peppersass wrote:That rings a bell. I think I looked for one of those when I was contemplating installing a Slayer-like needle valve, which would have required custom tubing to mate with, among other things, the block where the HX connects. Never could locate that male nut, which made me think perhaps it's a custom part made to LM specs.

You might consider replacing the check valve that was installed in the mixing valve. It's brass, while the current part is nickel-plated. Looks like the other check valves are nickel-plated, too. That suggests the brass check could be original equipment, and hence pretty old. They're expensive to replace, but better safe than sorry.

I don't think LM has the market cornered on these fittings, as I have them on my Rancilio, as well. You could easily make one by drilling out a reducer bushing or plug to clear the pipe. It's just odd that they dont seem to be an item that consumers can purchase.

I gave the check valve a thorough inspection. It shuttles as it should and seals as it should. These simple devices either work or don't. I'm not even sure there's a soft sealing surface inside of it. Many check valves just use the service pressure of normal operation to self-seal, so I am confident it's still doing its job given its internal condition. Though I understand and appreciate the advice (and it is good advice), I think I'll roll the dice.

Chert wrote:How many fittings must one redo before being able to rebuild a machine and be certain that upon activating, everything will work without leaks?

The answer?

At least one more

Cheers!

- Jake

On an aside, I think the brass check valves were replaced by plated ones. But since then LM has (I think I read somewhere) switched to full stainless steel check valves.

LM are moving to no copper no brass at all.

Correct.
The B.2.008 is no longer available (or at least being phased out).
**Edit**
Interesting that LM has a mix of brass and plated check valves in their own update literature:

Image: GS/3 Updates #5 from here

If you zoom in on the original, you'll see that the boiler fill check valve is plated, but all others are brass... They also have the steam boiler OPV fitting installed backwards nevermind, it's good...
Cheers!

- Jake

Stainless steel is lower cost. This is always sufficient justification for the manufacturer to change the new production to SS. The market likes SS as it is assumed to be absolutely safe and environmentally friendly.

Peppersass wrote: You might consider replacing the check valve that was installed in the mixing valve.

Jake_G wrote:I'm not even sure there's a soft sealing surface inside of it...

...I think I'll roll the dice.

Lucky for me I know that I'm no good at dice games.

Image: Check Valve-Disassembled

Ok.

Note to self: when Dick suggests something, just go with it.


I hooked up the plumbing supply line and when water started pouring out of the check valve in the wrong direction, I figured I had very little to lose. Once the snap ring is out, you are forced to sacrifice the O-ring to get it apart:

Image: Torn O-ring and Plunger


Assembly requires putting it together sans O-ring and then compress the spring and slip the O-ring over the plunger from the outlet side of the valve. I'll grab a bag of O-rings tomorrow and see how the rebuild goes.

Cheers!

- Jake

So will you be doing this on all of the check valves? My guess is that they'll all be on their last leg...

One of the reasons the GS3 is so expensive are these check valves. The entire water mixing subsystems are there for throughout (hot water conservation) and the check valves are mainly needed for these mixers. Sometimes withstanding 9bars (as in the tea mixer line - hence the doubling of the check valve).

AssafL wrote: So will you be doing this on all of the check valves? My guess is that they'll all be on their last leg...

Hooking them up to the supply line and testing them?

Yes.

O-rings are cheap.

The tea water check valves are really the most critical and have the hardest life. They withstand a ~7 bar differential every time you pull a shot and they are the most likely to have crud pass through them when they flow forwards given their location at the bottom of the steam boiler. If I have another leaker, I'll see if I can fish the O-ring out with a pick instead of extruding it to get the stem out (you have to push the stem past the seat to disassemble the B.2.008 check valves).

Cheers!

- Jake

Try and figure out what material was used for those o-rings and the durometer. Good place to go shopping: https://www.mcmaster.com/o-rings That look like it might be a brown viton o-ring. You can filter by color on the McMaster o-ring page and they stock metric sizes.

Jake_G wrote:Hooking them up to the supply line and testing them?

Yes.

O-rings are cheap.

Why test when you can replace? .

While it is broken down keeping a "soon to be a C-ring" is rather false economy. Giving them a new and refreshingly elastic o shaped ring is a great way to keep the next "not quite a full restoration" 10 years out.

Some parts are expensive, like the solenoid plungers, so I'd wait for them to fail. Some should not be repaired (like the OPV) - and have to be replaced (regarding the OPV, I guess one needs a 2.8 bar source to repair it. Replace any seal, hook it up to 2.8 bar and tighten until it barely shuts; repeat 10 times).

Some fittings, like the steam valve and steam boiler emptying ball valve, and the group seals are all easily repaired when needed and don't need the machine to be broken down.

But the check valves and boiler Orings need massive disassembly. I'd replace them all

AssafL wrote:Why test when you can replace? .

While it is broken down keeping a "soon to be a C-ring" is rather false economy. Giving them a new and refreshingly elastic o shaped ring is a great way to keep the next "not quite a full restoration" 10 years out...

...But the check valves and boiler Orings need massive disassembly. I'd replace them all

I hate you right now.

Some fittings, like the steam valve and steam boiler emptying ball valve, and the group seals are all easily repaired when needed and don't need the machine to be broken down.

Indeed.

Speaking of ball valves, and how I should really be listening to you and Dick...

Image: Steam Boiler Drain Valve-Disassembled

The control shaft O-ring came off in 3 pieces... any general tips for a successful reassembly?

Cheers!

- Jake