Conti Prestina Espresso Machine Restoration 101 (Completed and Indexed) - Page 43

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

#421: Post by drgary »

Pipe Fitting

Today I had a chance to do some pipe fitting. It wasn't easy but wasn't too hard a challenge either. The Teflon tube I had didn't look like it had enough length to put the PSTAT where I wanted it -- with the adjustment screw facing forward. I had cut off one end of the Teflon tube to free the fittings and re-use them with copper pipe. That position was not to be, however. The only place this large PSTAT fits is as you'll see below, with the adjustment screw facing down through the bottom of the frame. By now I was committed to copper pipe, but the 1/4 inch pipe I had didn't fit through the opening on the 1/8 inch pipe fitting. I eyeballed the sizes of the compression sleeve and pipe and realized the threads of these nuts would still be intact, so to fit the pipe through there I would need to drill out the hole in the top, which I did.

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Next I had to cut and bend pipe. I did the cutting with a rotary tool cut-off wheel and filed the end to square and debur it. Where the tip of the pipe was slightly distorted I reshaped it to round using needle-nosed pliers. I think this compression fitting will work. The sleeve is smaller diameter than the flat surface where it mates and the threads in the nut weren't damaged during drilling. There is another kind of compression end that fits inside the pipe and is flat. Usually that mates with a gasket, which I can make if needed from Teflon or Viton. For any of you experienced hands, does it look like the sleeve that's in place will work? When I tighten it down it stays put.

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Bending of the pipe was an art project, being careful to not kink it. I bent this pipe by hand, which took a combination of moderate hand strength and restraint to gently create many small bends in the directions wanted. Although there was a slight kink where the pipe was still open, I put the pipe in a vise and gently tightened it down to open that bend a little.

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Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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orphanespresso

#422: Post by orphanespresso »

Holy Cow, you sure went about cutting that tube the hard way!

Do you have a plan for adjusting the inverted pstat? Will water accumulation in the pstat be a problem?

Are you sure the vac valve will work horizontally? What happened to the nifty drainey tray?

Questions questions..

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drgary
Team HB

#423: Post by drgary »

Doug:

I thought I just had to fit the pieces together and they would work. You mean they need to face right side up??? It's a challenge to fit that big PSTAT in there! :lol:

Okay, the drainy thing is off to the left.

So now, which way must things be facing? I've got more pipe I can bend and have had some practice. By the way how do the terminations look for that pipe?

Also the PSTAT is sitting there without the housing that will attach it to the frame. I positioned it there for fitting. I want to have the adjustment screw facing forward or down or I'll have to take off the panels every time I want to adjust the thing.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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orphanespresso

#424: Post by orphanespresso »

Fittings will be fine if they hold.

I think you might contemplate what is called a more "sanitary" plumbing job, as you have way too many fittings to worry over here...

I would suggest a 'T' fitting on top where the pressure valve is, put the vac on the top of the T and the pressure safety out the side then run a copper line under the boiler and install your pstat on the other side where you have no other tubes in the way. Install the pstat right side up so it does not get waterlogged and adjust it from above if needed. You will likely not be changing the setting very often once you get it all set up with the case off so instant access will not be needed. Unless of course you have invested in a mechanics creeper to get underneath the machine for pstat tweaking through the hole in your granite countertop :wink: .

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drgary
Team HB

#425: Post by drgary »

Thanks, Doug. That seems like a good plan with one exception. The boiler is offset to the right so there's more room inside the case on the left. Thus pipes may need to cross over each other. Now the difficulty again is getting the T fitting and properly hooking up the pressure ones. I'll go home and measure what's there and post it in case you have the T and anything else needed. An alternative is to work with what I've got but turn the PSTAT upright. This might give me what I need to finally test this machine before doing a plumbing clean-up later.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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orphanespresso

#426: Post by orphanespresso »

I'll have a look at a Prestina and see how I would do it...but that would of course ruin your fun.

By the way, a small tubing cutter costs like a buck ninety eight and is a very handy and useful tool as well, particularly for cutting tubing. :D

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drgary
Team HB

#427: Post by drgary »

Doug:

Please ruin my fun. Any help so I can get this baby up and running will be so appreciated. :roll:

The pipe cutter's a good idea, and to this newbie restorer it never came to mind. The cutting wheel and filing was quick and easy, though.

Some of the fittings that were sent as part of that Teflon tube assembly are held together with Loctite. How do I get them apart, or is it better to source another pressure release valve?
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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orphanespresso

#428: Post by orphanespresso »

This setup is what I had in mind
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The 3/8 T can be gotten in any combination of male and female on which part of the T. This one is the only combo I have so I had to use a second fitting (brass color)to go from 3/8 to 1/4 so the vac valve will plumb in using a 1/4 female female. If a person had every possible fitting it could be done with a 3/8 T, a 3/8 to 1/4 female female adaptor nipple and then the vac valve to save one fitting. All of the fittings are assembled with teflon paste on the bench and then installed since there is not enough room in there to thread them together and tighten in place. But this takes the vac off the pstat line.

Now, you can go directly to the pstat using the original line with compression fittings that you have and make a simple L shaped tube (the shorter the better) which will be easier to both bend and install than the over under around and through system you are working on. Seems that one can install the pstat like this.
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Try heat gun or propane on the Loctite and give your old pressure safety a good look as it does have a replaceable seat inside there and a spring...but you likely know this. For true safety you might want to consider a homologue as they call them....tested and certified, usually 1.8 bar rather than the set and forget and regret valve currently on the machine.

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drgary
Team HB

#429: Post by drgary »

Thank you, Doug. I see you have a Prestina. I can fix that up in a jiff. It only took me almost two years to get to this point on mine! :shock:

Do you have a homologue you can sell me and a T fitting and if needed an adaptor? Also Teflon paste? Or will PTFE plumber's tape do as well? I've got 1/4 inch copper tube, compression nuts and caps and of course the PSTAT with a metal housing. Also do you have a strain relief for the power cord that will match a black frame?

The assembly you have there, modified to include the vacuum breaker, does not now attach to the bracket that formerly braced the back of the manometer. I suppose I can work that out as I would need to do with mounting the PSTAT. Your Prestina looks identical to mine, at least in its junkyard phase. Is it also a "La Cara"?
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

User avatar
orphanespresso

#430: Post by orphanespresso »

Oh yeah, the bracket....seems a bit more tinkertoying needs to be done to send what would be best called a manifold out the side and away from the bracket instead of directly back and directly up...hmm. It seems that you are all set up to work out the pstat with your compression fittings etc so while you continue to tackle that one I'll fiddle with this dual vac valve safety valve area and see what I can come up with.

Teflon tape yes.

La Cara badging yes.