How to adjust steam pressure of Zacconi Riviera

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timmangan
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#1: Post by timmangan »

I have a Zacconi Riviera and I want to adjust the pressurestat, reduce pressure.

Does anyone know how to do this?

I have pics of the pressurestat attached, any help would be greatly appreciated.

Thanks guys.




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cuppajoe
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#2: Post by cuppajoe »

I have the same one in a Riviera I have been overhauling. It looks like the adjustment is the chrome knurled screw that impacts the pin on the microswitch. Mine has what looks like a set screw, so loosen that before attempting to adjust. My guess is that screwing it outwards will set it to a lower pressure, but not sure. First experience with this variant and haven't actually used it yet.
David - LMWDP 448

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

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RioCruz
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#3: Post by RioCruz »

Yes, the knurled nut adjusts the pressure. It has holes drilled into it that makes adjusting it easier by sticking a small rod (nail, etc.) of some sort into the holes to help turn the nut.

I THINK turning it counterclockwise lessens the pressure, clockwise increases the pressure...but I can't remember for sure. Mine doesn't have a set screw.

I have mine set at about .8 bar. Seems to be about right for me.
"Nobody loves your coffee more than you do."
~James Freeman, Blue Bottle

timmangan (original poster)
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#4: Post by timmangan (original poster) »

Riocruise: thanks for the reply, what do you mean by the knurled nut?

Cuppajoe: Im sorry man, but i didnt follow your reply. Can you make it a bit simpler for me? I am an Aussie after all... :)

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RioCruz
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#5: Post by RioCruz »

timmangan wrote:Riocruise: thanks for the reply, what do you mean by the knurled nut?
Oh...sorry 'bout that. It's actually a big knurled screw. The first photo you posted shows it well. It even shows one of the holes I mentioned:
"Nobody loves your coffee more than you do."
~James Freeman, Blue Bottle

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cuppajoe
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#6: Post by cuppajoe »

timmangan wrote:Riocruise: thanks for the reply, what do you mean by the knurled nut?

Cuppajoe: Im sorry man, but i didnt follow your reply. Can you make it a bit simpler for me? I am an Aussie after all... :)
Basically the same info as Rio, but the one I have looks like it has a set screw on the body to lock the adjuster once set. My machine is in pieces and in storage, so no way to confirm operation at this time.

Or just start whacking it with that big knife all you folks carry...
David - LMWDP 448

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

timmangan (original poster)
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#7: Post by timmangan (original poster) »

Well, i got the machine apart yesterday and had a go with the info I had, and it seems like... the info was good :)

I have attached a couple of pics to help someone else who might want this info later.

The copper nut has a little hex screw that keeps it in place, so first i had to undo that, and then i rotated the nut half a turn counter clockwise.

This made an incredibly small difference in pressure, noticeable, but nowhere near as much as i thought half a turn was.

The only problem is though, that even that half a turn made it really hard to fit back into place. As the copper screw rises as it is loosened, it pushed up on the pressurestat, i don't think there is actually anymore room to undo it before it wont fit back in at all. Another half a turn would be nice, but just doesn't seem like it will be possible.

But, it did work, not as much as i hoped, but its better than nothing. If anyone has any tips on how to further reduce pressure, please let me know.

Thanks for all the help guys, hope this helps someone else as well.

Cheers

timmangan (original poster)
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Joined: 8 years ago

#8: Post by timmangan (original poster) »


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cuppajoe
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#9: Post by cuppajoe »

I dug mine out and pulled it apart to see how it was engineered.

It was pretty badly scaled, so not sure what is inside the main body to actuate the rod, could be a piston or a diaphragm. In any case, steam pressure pushes on the first disc, which compresses the spring, which is adjusted by the large 'screw'(chromed in this case). The rod is pushed by the first disc and impacts the pin on the microswitch, opening the contacts and cutting power to the element.

Near as I can tell, the adjustment screw increases or decreases the spring pressure, which adjusts the point at which the rod impacts the switch. Looking at it, it seems a rather gross adjustment, so may take quite a bit of travel to make much difference. If unable to bring it into spec, my first move would be to descale and clean.

What was interesting is the switch is made in the US, and possibly the whole pressurestat. Seems Universal Control may be no longer in business.
David - LMWDP 448

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

timmangan (original poster)
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#10: Post by timmangan (original poster) »

So after a week or so of use after I adjusted it, the ticker turns on lower, but still turns off way up in the red.

I did lower the on, but just not the off, i guess.

Any ideas of how to adjust the top end, not only the low?

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