Faema Urania single group, v.1 Project - Page 15

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
ira
Team HB
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#141: Post by ira »

I'm not a lever guru, but I own one. I would guess the top seal is to keep water from escaping while the piston is down and the bottom seal is to create the pressure to brew. Water between the two seals is just a by-product of the design, unless water circulates between the 3 holes and warms the piston when the lever is up.

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cuppajoe (original poster)
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#142: Post by cuppajoe (original poster) replying to ira »

First off, the replacement seals are not as original. The top seal is a U-cup, as original, but the new lower seal is a 'W' configuration. Not sure if this matters or not.

When the piston is down, both seals are below the injector ports. The top seal faces down, so blocks water from going up. The W seal on the bottom acts like a seal during extraction, keeping the the water column pressing through the shower. It also acts like a seal going up. Forcing the water backwards through the injector ports on it's way up. This would not be the case with a U-cup in the bottom slot.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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Paul_Pratt
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#143: Post by Paul_Pratt »

There are a few ways to set those seals up on the Marte group since the seals are indeed below the inlet as it is a saturated group. You can use 2 V rings or 1 V and 1 X (W) seal. I've always used a V and an X.
  • If using 2 V rings you would have the top one as a V and the lower one as an upside down V

    If using the 1 V and 1 W you would have the top one as a V and the X on the lower one

All other Faema groups have the water inlet holes inetween the 2 seals so you would use the V and X configuration but the V seal on the top is upside down.

I may have confused you by email, it is confusing.

The other point to note is that there are 2 sleeve sizes on the Marte. The regular seals which you have are hit and miss on the larger bore sleeves, which is why you will often find seals on top of pistons that have been padded out with teflon tape, to make the seals seal better.

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zeb
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#144: Post by zeb »

First time you must open the top cap behind the unit to purge the air and raise the water. Did you do it David?

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cuppajoe (original poster)
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#145: Post by cuppajoe (original poster) »

Thanks for chiming in Paul -

I think the top seal is upside down to how it should be, will pull it to confirm. If I get your drift, the top seal should be with the sealing lip up(V). By "seals below the inlet" are you referring to the piston in the raised position, or down?

When I reconfigure the top seal I'll go back to the original O-ring at the top.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

Marcelnl
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#146: Post by Marcelnl »

great to have such expertise in this forum! Does anyone know of a finding place for things like explosion diagrams for the various versions of the Urania? At some point I'll have to replace a seal I figure, and currently I wonder if the upper lever rest should have a bumper like the lower position...not that I worry but the upper side has a hollow part that puzzled me when I first noticed it.
LMWDP #483

kitt
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#147: Post by kitt »

Yes, there should be a rubber bumper in the back-rest, found here in the exploded view and the second item in the parts list;

https://www.tse.at/au/shop/index/cat/c2 ... 1b84e6d69e

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cuppajoe (original poster)
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#148: Post by cuppajoe (original poster) »

Yes, both bumpers are important to prevent metal to metal contact at both ends of lever travel, especially when/if the lever gets away from you. Keep in mind that the parts illustration and numbers are for the latest group version, often referred to as the Zodiac group. The earlier Velox variant is different, tho shares some parts like seals. The Earliest Marte group is a totally different animal. I have found very little reference material.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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zeb
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#149: Post by zeb »

2012 I had post this picture on a forum about the seals of the Marte group piston. Quick Ms Paint drawing but everything has been measured with precision before.



If it can help ;)

ps: Repos = Idle, Pré-infusion = pre brew and extraction = brew

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cuppajoe (original poster)
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#150: Post by cuppajoe (original poster) »

Thanks Pascal -
You posted that just as I was. Your illustration shows pretty much what I thought should be going on. Will add more on the other thread.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits