Stupid question

[birzzz]

In one of the article of BYO this month, it says "slightly open the PRV" on the SS Brewtech unitank. How do you "slighty" open up the PRV exactly?

The article:

https://byo.com/article/the-hop-dropper/
Thanks and sorry if it seems dumb.

 

[VikeMan]

In one of the article of BYO this month, it says "slightly open the PRV" on the SS Brewtech unitank. How do you "slighty" open up the PRV exactly?

Can't see the article and I don't own an SS Brewtech unitank. But I assume they mean... open it enough to relieve pressure, but not fully open, i.e. keep the size of the opening to a non-zero minimum.

Have you ever just barely pulled the PRV on a corny keg, so that gas sort of "spits" out rather than a full "whoosh?" Like that.

 

[rsquared]

The SS Brewtech Unitank uses an adjustable PRV (aka Spunding valve).

 

[birzzz]

The SS Brewtech Unitank uses an adjustable PRV (aka Spunding valve).

Actually this is the PRV included with the 7 gallons Unitank, the 3' TC one: Pressure Relief Valve | Replacement PRV

I was wondering if by adjusting he meant using a tool that goes into the square hole on top of the valve or loosening up the tri clamp... I have emailed BYO to have more details. As of now I don't have any tool that fits the hole, so I cannot test that out.

 

[Vale71]

The PRV is non-adjustable, like a true PRV should be. If you unscrew the top portion all you'll be able to do is remove the spring and plunger for cleaning purposes. Doing that when there is pressure in the vessel could result in serious bodily harm, so don't!

I too don't have access to the article and I suspect the author might have been talking about a vessel that he hasn't actually had a chance to use in practice. The only way to safely release pressure on an SSB Unitank without purchasing extra accessories like an adjustable spunding valve is to crack open the valve at the end of the blow-off. This is however rather crude and if the tank has more than 0.2-0.3 bar of pressure your ears will resent your doing that. Ask me how I know...

 

[Vale71]

The SS Brewtech Unitank uses an adjustable PRV (aka Spunding valve).

Only if you purchase it as extra.

 

[duncan.brown]

Take a look at this video, which might help:



I do what this guy does, which is to use 3” triclamp plate from my Chronical with a gas connector installed instead of the blowoff hose barb. The lower pressure PRV on the Chronical is easier to manipulate by hand than the one that comes with the unitank.

If you don’t also own a Chronical, here’s the part:

https://www.ssbrewtech.com/collecti...17-mm-blow-off-hole-and-pressure-relief-valve
The hole is (annoyingly) slightly larger than a 1/4” NPT thread. You need a several o-rings to get a good seal. You could also ask @Jaybird as NorCal has a bunch of parts that would do the trick. I use their yeast brink as the hop dump.

 

[birzzz]

Take a look at this video, which might help:



I do what this guy does, which is to use 3” triclamp plate from my Chronical with a gas connector installed instead of the blowoff hose barb. The lower pressure PRV on the Chronical is easier to manipulate by hand than the one that comes with the unitank.

If you don’t also own a Chronical, here’s the part:

https://www.ssbrewtech.com/collecti...17-mm-blow-off-hole-and-pressure-relief-valve
The hole is (annoyingly) slightly larger than a 1/4” NPT thread. You need a several o-rings to get a good seal. You could also ask @Jaybird as NorCal has a bunch of parts that would do the trick. I use their yeast brink as the hop dump.

Thanks for the answers, I had already saw this video and this one is pretty straight forward when it comes to releasing the pressure. If I ever go that route, I will do something similar, I don't think with the PRV that comes with the unitank you can easily crack it open the way it is said in the article.

Cheers guys!

 

[NeoBrew]

You might be able to loosen the tri-clamp without taking it off and let pressure out, but it is a risky proposition. I have the 7 gallon unitank and do pressure transfers to the keg. I once forgot to depressurize the unitank afterward and undid the PRV to start cleaning. It scared the crap out of me when it popped open and the PRV bounced up a couple inches. Fortunately there was not enough pressure to really hurt anyone!

I don't think this would be a reliable way of venting unless you start with zero pressure in the vessel and then either purge with CO2 or make sure you do it before fermentation is done. If you let it pressurize and then popped the top off I would fear killing the yeas with the sudden pressure drop.