Battling some GS3 nuts

#1: Post by **OkcEspresso** » August 12th, 2020, 10:11 am

In a semi-catastrophic failure, the gasket on the heating element side of the steam boiler gave out. Lots of steam, water and cleanup and and even bigger job to replace it. You have to remove and loosen a ton of pipes and nuts to get it out. This happened in January of this year but due to Covid, a couple of the parts did not arrive until this week. I am now trying to reassemble everything but the two nuts in the center of this photo appear to require a shape-shifting tool that wont be invented for another 400 years.

Does anyone have a technique or yoga chant that might assist with getting these two tight enough? The chore is compounded by the fact that the silver box thingie wants to move around while you tighten everything.

August 12th, 2020, 12:17 pm

Why not just ask LM what they use if you think its so unique?

August 12th, 2020, 12:26 pm

Espresso technician here...

Those nuts are tricky. A lot of times you've got to remove other parts and components to access the ones you're trying to get to. It's definitely a pain.

I'd recommend a pair of channel locks to stabilize the silver square component, and get a wrench that fits those bolts exactly (looks like a 14mm maybe?). The key is to stabilize the components you're tightening, otherwise those copper tubes can bend and break. You could also try a very little amount of thread tape, and don't worry too much about over tightening.

Let us know how it goes.

#4: Post by **Jeff** » August 12th, 2020, 12:39 pm

I found that a set of good-quality flare wrenches make working on these fittings a lot easier.

August 12th, 2020, 1:15 pm

I think you are right. Flex head flare wrenches are probably the ticket. Going to pick up a set today.

https://www.amazon.com/Piece-Flex-Head- ... 07876M87B/

Thanks!

Chris

#6: Post by **trumz** » August 12th, 2020, 4:04 pm

I was in a similar situation with a GB5. Since I had everything dismantled and out of the machine, I put the whole thing in a vice and tightened the nuts then reasembled.
If you're really having a hard time getting those tight, remove the assembly and tighten while held in a vice. Although those fancy wrenches linked above should do the trick. I need to get myself a set!

#7: Post by **Peppersass** » August 12th, 2020, 4:41 pm

Flare wrenches will work.

Caution: Immobilize the mixing block while you unscrew the nuts. I use a screwdriver inserted into the hole in the upper right to do that. Also, carefully loosen the nuts at both ends to relieve tension on the pipes (i.e., don't unscrew one end with the other fully torqued.) If the block moves with the pipes under tension there's a chance that the pipes may split near the nipple that's inserted in the mixing block and will have to be replaced.

The risk is that the pipes may be weakened behind the nipple due to threads for the 1.5mm gicleur (flow restrictor) being tapped too deep -- past the nipple and into the softer copper tube. That creates a weak spot that can split under lateral pressure.

I found this out recently when I installed a "Jake Valve" for flow control. Unscrewing the nut of the top pipe moved the mixing block, causing a leak from the lower HX tube inside the mixing block. When I removed the tube I found that the nut showed signs of a prior leak -- some green scale had seeped into the threads:

I suspect that a very tiny split developed in the tube when I replaced the seals on my steam boiler about nine years ago (mine was a slow leak rather than an explosive event, but the leak killed the logic board.) My machine is a "fire sale" GS/3 from the vintage 2008-2009 serial number range 500-700, some of which had issues with the steam boiler seals -- among other problems.

Anyway, I think the leak had been there a long time, but was so tiny that the water evaporated off the threads before doing any damage. Movement of the mixing block to install the Jake Valve caused the split to widen and a much larger -- and visible -- leak resulted. It turns out the gicleur threads were almost 1/2" deep, extending well past the nipple. You can actually see the thread marks on the outside of the tube (the split is just under the solder):

Luckily, I ordered two replacement pipes because when I removed the other one I found it had a split, too:

(And, surprise surprise, the upper pipe had a 1.5mm gicleur, too, which I don't believe is supposed to be there (it's not in the parts diagram.)

The split in this tube might have developed as I removed the tube to replace it, or the tube could have been weakened back when I replaced the boiler seals but not enough to split. The gicleur threads weren't tapped anywhere near as deep, but they did extend past the nipple.

There are no thread marks on the outside of the replacement tubes and the threads appear to stop before the end of the nipple (hard to tell for sure):

Needless to say, I was very careful when replacing the tubes, being sure to keep the mixing block from moving and alternately and gradually tightening the nuts at both ends.

Hope this helps.

#8: Post by **stefano65** » August 12th, 2020, 5:47 pm

The linked ones above looks nice but you can go cheaper with curved ones like so as well

NEVER MIND the pipes are connected with no entry
they will work only if you cut a slot like this one then

#9: Post by **chrisvarghese** » August 13th, 2020, 5:51 pm

When I replaced the seals on my gs3's heating elements, I was given the advise to make up the connections for the thermo mixing valve before placing it back in. Not sure where I got this advise from, pretty sure it was from this forum.

So, essentially, you'd make up the connections for the 3 tubes into the thermo block and then place it in the machine and just make up the other ends which go into the boiler etc.

Hope I'm making sense

#10: Post by **ira** » August 14th, 2020, 1:45 pm

Peppersass wrote: The split in this tube might have developed as I removed the tube to replace it, or the tube could have been weakened back when I replaced the boiler seals but not enough to split. The gicleur threads weren't tapped anywhere near as deep, but they did extend past the nipple.

If I was guessing, I'd say those splits were caused by vibration of the parts over time causing the metal to harden and then crack. Probably helped along by the difficulty of installing that with none of the pipes under stress. Seems like if it ever happens again and there's room, you might consider loops in a couple of the pipes to relieve the potential for stress. That's a lot of short pipes connecting three different things together in something with a lot of movement, thermal or physical.

Ira