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Pressure Barrels - More than you wanted to know!

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PenhowBrewer

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Firstly, I think I’m going to cut and paste all of this “KK Maintenance manual” into a word document, print it out and stick it in my brewing folder)! it‘s such a useful reference.

Having read thru a couple of times, I cleaned out my KK top tap barrel yesterday, and dug out a couple of (clean) fine steel files and filed away and made sure I had a nice, burr-free, flat, smooth surface around the neck of my barrel. It took a while, and the noise didn’t please SWMBO very much (see had decided to do some ironing in the kitchen to keep me company).

I then checked all the seals etc around the pin valve assembly, as per this post, and re-checked my ‘bodged’ Schroeder valve and pressure gauge fittings. The only thing I haven’t done yet is the plastic zip-tie tip. I know I have some but couldn’t lay my hands on them yesterday.
I had also recently bought a square cross section ‘O’ ring from Ballioo, so replaced the round cross section one with this new one. It’s a nice, fat squidgy item if anyone has been thinking about getting one.

I fitted the cap, gave it a tighten, and with a bicycle pump, pumped it up to just over 3 psi. I smeared diluted washing up liquid around all the fittings and waited....

so this evening it’s STILL at just over 3psi 😀👍, that’s about 28 hrs. So I thought I would put a bit more pressure in tonight, and see how it goes. 🤞🏻
 

kelper

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a car tyre pump is easier. Fill the PB with water nearly to the brim so you won't need to add much air. Then check it dispenses only water, no air.
 

PenhowBrewer

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Great tip..I hadn’t thought of that.
having said that, it’s a great bit of cardiovascular exercise pumping the damn thing up🥵
took it to 5.5psi yesterday evening, and it’s still there now. So I’m pretty chuffed about that. I may just have a fully working KK 😀
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kelper

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You should pump it up to 12psi - the relief should open before then.
 

PenhowBrewer

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You should pump it up to 12psi - the relief should open before then.
So, I pumped it up to just under 12psi, and I could clearly hear the safety relief valve hissing, so that showed it was working.
trouble was the pressure kept on dropping over the next few days until it was just a bit higher than the 5.5 it had sat at in the previous post.

So I resat the various items of cap hardware and replaced a few washers etc, and pumped up to just over 9 psi and waited. The pressure started to drop a bit, so out with the washing up liquid, and it was the relief valve again! very slowly, but that’s where the air was coming back out, but very slowly.

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But then it stopped at just about 9psi.
That set me wondering how accurate these gauges are. I’ve got a bike tyre gauge somewhere, so I’ll have to dig that out and do a comparison. But if it hangs around this sort of pressure - given the good ‘whoosh’ of air coming out when I opened the tap - I think it should be fine.

i have also put a mark on one of the cap flanges (a dab of SWMBO’s nail varnish) and a mark on the barrel on a sticker, so I know how much I have tightened up the cap.

So, once my red wine kit is off the heating pad, I’ll get my weissbier kit under way and into the newly tweaked KK!👍
 
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kelper

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The rubber washer is not set to any pressure. 9 psi sounds fine to me. If it did not relieve by 12 psi I would wonder if the hole was blocked or if the thing was sticking due to dried sugar
 

Buffers brewery

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Not advocating this for everybody, but I gave up on rubber band safety valves months ago. I use a radiator bleed valve fitted to a tee piece that a pressure gauge is fitted to. The tee piece is plumbed into the cap. IMO you only need pressure relief during carbonation (if you use a S30 brewgas cylinder) and as the pressure increases any excess can be vented (daily) until carbonation is finished. No rubber bands. No leaks. Simples. But not for everybody.
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terrym

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Under the general heading of 'Safe Brewing' you should not pump up a PB with air alone to its maximum allowable pressure. It's much safer to fill it with water leaving a little headspace (ullage) and then slowly pressurise that if you need to test. If a PB splits under an air only pneumatic test (however small that risk might be) the consequences can be catastrophic due to expanding gas, whereas if a test is done with mostly water in the PB there is much less air that can expand should the PB fail. In an ideal world you should be testing PBs with water alone (hydraulic test), but for most homebrewers that is impractical.
 

Buffers brewery

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Stating the obvious but don't use CO2 to pressurise the partially water filled PB and leak test by monitoring pressure alone as the pressure WILL drop as CO2 dissolves into the water irrespective of leaks.
 

Hagrid

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Does anyone know what size hole in the cap is needed for an S30 valve? I’ve dug out a pressure barrel and the (none S30) valve is corroded so I’m going to replace it. I’m hoping it’s either the same or bigger than I’ve already got...!

I’ve already got a blow off in the cap but I don’t suppose it’ll hurt to have an S30 with another will it?

Obviously I’ll be changing the rubber O rings too. Just need to measure them.

Thanks again everyone!
 

kelper

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Does anyone know what size hole in the cap is needed for an S30 valve?
The OD of the S30 valve is 17.5mm but it has two flats at 14.8mm. The hole also has two flats to stop the valve turning. The hole 'diameter' is 18mm and I'm sure a round hole would be fine.

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Hagrid

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Thanks Kelper. The flat sides are just to hold the valve as you tighten it, so I should be fine. The hole in mine is 16mm, so I can drill it out a touch. :)
 

kelper

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Warm the plastic first, to make it less brittle. It's easy to crack. A sink of hot water would do the trick.
 

Buffers brewery

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A word of caution. I fitted an S30 valve to the lid of my FV and, although I tried to replicate the 2 flats, my hole came out a bit big so the valve could rotate. When I used it, undoing the cylinder from the valve was a bit scary as the valve rotated with the cylinder and didn’t turn off immediately. Make sure you have a 15mm spanner handy.
 

Hagrid

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Or just buy a new lid pre-punched. £3
I did consider that. The PB I’ve got is an old boots one. I wanted to try it out before splashing out on a KK.

My concern was if the threads matched?

I never make it simple....
 

Coffin Dodger

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I thought I knew every dirty trick that cheap and cheerful pressure barrels could play, but this is a new one. Alerted to a problem by a trickle of beer coming out of the drain on my ancient chest freezer beer store, I tracked it down to a hairline crack on the centreline at the bottom of the circle. Seepage stopped when I dropped the internal pressure from 5 psi to zero, and as this particular cask was due to be used next, stuck a bit of ubiquitous Gaffer tape over the crack and connected up my mini hand pump and Noddy foil balloon air excluder. (See my thread ‘Draught beer’ if that is gibberish to you.)

Yet another scrapped PB, but not a financial disaster as it was one of a pair my assistant brewer produced from somewhere for free. There is a saying I learnt from my Dad which goes: “In this world there is always a man prepared to make things a little cheaper and a little worse, and those who buy on price alone are that man’s lawful prey”. I suppose I should have standardised on King Kegs, but five of them won’t fit in my beer store.
 

kelper

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Maybe the cold made it a bit brittle, was it touching part of the fridge that gets very cold? I guess the tap keeps it away but was it close?
 

terrym

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View attachment 33512

I thought I knew every dirty trick that cheap and cheerful pressure barrels could play, but this is a new one. Alerted to a problem by a trickle of beer coming out of the drain on my ancient chest freezer beer store, I tracked it down to a hairline crack on the centreline at the bottom of the circle. Seepage stopped when I dropped the internal pressure from 5 psi to zero, and as this particular cask was due to be used next, stuck a bit of ubiquitous Gaffer tape over the crack and connected up my mini hand pump and Noddy foil balloon air excluder. (See my thread ‘Draught beer’ if that is gibberish to you.)

Yet another scrapped PB, but not a financial disaster as it was one of a pair my assistant brewer produced from somewhere for free. There is a saying I learnt from my Dad which goes: “In this world there is always a man prepared to make things a little cheaper and a little worse, and those who buy on price alone are that man’s lawful prey”. I suppose I should have standardised on King Kegs, but five of them won’t fit in my beer store.
Add pinhole leaks in the body that squirted a tiny jet of beer, cracks along the seams in different places, cracks at the bottom away from the seam, cracks in the cap, caps that don't pull down on the gasket properly because the thread is too coarse (Hamilton Bard), let alone leaks from the any of the gaskets.
In short not fit for purpose, but they have really been that way since the 1980s when the first ones came on the scene, since the design is the same, and I found that out the hard way like others.
 
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