Extra steam in Silvia's boiler after pressure mod...

[richardtempura]

Hi guys,

I recently adjusted the OPV on my Silvia, the extra copper washer thing.

I'm really happy with the results!

But one thing's bothering me: I always have extra steam in the boiler.

Before I adjusted the OPV, if I flushed out the extra steam via the steam wand or group flush and only did espressos, no steam would build up in the boiler. It would fill up and everything was ok.

Now, I have to flush after every shot. Mmmmhh.....


So my question is: what's going on?

Is the OPV acting up someway that I didn't anticipate (or simply didn't read the fine print?)

or

I accidently touched something inside the machine (TC, thermostat)


Thanx in advance!

Martin

[HB]

Interesting, I noticed the same thing during the Bench's Rancilio Silvia Flash Review (Reloaded):

Maybe it's peculiar to Mike's machine, but Silvia seems to develop a 'steam pocket' in the boiler that must be purged after it's been idle, otherwise the group initially sputters water and flashes steam. Once this formality was out of the way and the PID recovered a couple minutes later, she was ready to go.

I don't remember if my old Silvia also did it. I was accustom to temperature surfing, so I probably wouldn't give much thought to an extra few bubbles when initial drawing water through the group. In any case, I don't think it's related to the pressure modification since its only effect should be limited to regulating maximum pump pressure (ergo "over-pressure valve / OPV") and allowing water to expand (ergo "expansion valve").

[barry]

In any case, I don't think it's related to the pressure modification since its only effect should be limited to regulating maximum pump pressure (ergo "over-pressure valve / OPV") and allowing water to expand (ergo "expansion valve").

it reduces the overall idle pressure of the boiler, and since boiling point is related to pressure, it reduces the boiling point of the water in the boiler as well.

[AndyS]

I recently adjusted the OPV on my Silvia, the extra copper washer thing.

I'm really happy with the results!

But one thing's bothering me: I always have extra steam in the boiler.

Before I adjusted the OPV, if I flushed out the extra steam via the steam wand or group flush and only did espressos, no steam would build up in the boiler. It would fill up and everything was ok.

Now, I have to flush after every shot. Mmmmhh.....


So my question is: what's going on?

Is the OPV acting up someway that I didn't anticipate (or simply didn't read the fine print?)

or

I accidently touched something inside the machine (TC, thermostat)?

An ideal OPV would stay tightly closed until it reached its exact set point, when it would open completely. As soon as the system pressure came down to just below set point again, the valve would shut completely.

Real world OPVs don't act this way, however. They crack open and begin dribbling well below set point. I suspect that the fiddling you've done with your OPV has increased its tendency to dribble. This means that the boiler may frequently be oozing a bit, and you have to refill it much more often than usual.

If you run the hose coming from the OPV into a cup, you can see if this is the case.

Otherwise, when you went into the machine and twisted things here and there, you may have created a small leak someplace else.

[richardtempura]

Thanx guys.

I always flush anyways so that's not a hassle.

Still, it seemed odd compared to the orginal OPV setting.

Is there any OPV's that are "tight"? Adjustable?

Or maybe I'll wait for upgrade fever to hit hard......

[AndyS]

Is there any OPV's that are "tight"? Adjustable?

Or maybe I'll wait for upgrade fever to hit hard......

There are lots of easily adjustable OPVs, but retrofitting one of them to Silvia might not be so easy.

When you go to a rotary pump, you can leave the OPV set real high where it won't leak. The rotary's bypass valve takes care of extraction pressure regulation.

[erics]

I purchased a fluid-o-tech OPV from WLL which is a standard part on the Brewtus and probably other Expobar machines and others. It is an easily adjustable OPV. I also purchased a 1/4 BSPP to 1/8 BSPP male adaptor and seal rings from this company - http://www.hoseandfittings.com

Other adaptor sources would be Swagelok and Parker.

The 6mm x 4mm x 21.5 cm teflon tubing which connects the pump elbow outlet to the OVP inlet will PROBABLY be about an inch or so short after applying the Brewtus OPV. Trying to find lengths of metric teflon tubing is, well, difficult unless you're willing to purchase 25 feet or so - which I was not. So I decided to convert Silvia using stainless braided 1/4" teflon hose and BSPP to 37 degree male fittings. The teflon tubing on Silvia is easy to remove at the pump end but the OPV end has seen quite a bit of heat and can be troublesome.

I probably should have left well enough alone but I was anxious to play around with an OPV that was easily adjustable "on the fly." As AndyS said - "retrofitting one of them to Silvia might not be so easy" and he is correct.

Eric S.