CO2 pipe diameter

[Sprocker]

Hi all,
I'm looking to build a gas distribution board to give me more scope. The board will be external to my kegerator feeding two kegs, and will also feed a fermzilla in my fermenting fridge
This will mean a 4 way manifold and some secondary regs.
Currently I have 5/16" pipe which is fairly rigid.
Is it OK to reduce down to 3/16" pipe, and if so when is it best to make the reduction?

 

[crowcrow]

Yes, they are gas safe and you can use this sort of thing to reduce the size of the tubing John Guest 5/16" - 3/16" Reducing Straight Connector PI201006S 665626053061 | eBay

 

[RoomWithABrew]

Worth using Eva barrier tube to limit oxygen ingress, lumen diameter not that critical for gas but much more important for liquid ie beer line. Flow is proportional to the 4th power of the radius so double the radius and flow increases 16 times, hence 1/4 inch beer line is very long in comparison to 4mm internal for a kegerator or the 2.5 mm for my party mini keg.

 

[Sprocker]

Yes, they are gas safe and you can use this sort of thing to reduce the size of the tubing John Guest 5/16" - 3/16" Reducing Straight Connector PI201006S 665626053061 | eBay

Do you know if its best to use a reducer, or could I reduce directly on the secondary regulator ? So 3/8 into reg 3/16 out of reg?

 

[crowcrow]

I don't see why that would be an issue, but hopefully someone more knowledgeable than me can pitch in. I've found John guest fittings to be very good under pressure.

 

[peebee]

John Guest fittings are okay I suppose. Readily available and everyone here seems to love them. Bit dodgy (leak) if too much bending on the pipes but that's really because of the super stiff polythene (MDPE) pipes; you are probably okay with the 3/16" stuff, but I've seen one report of it bursting in a homebrew situation well under specified pressure (QC issue?).

Me? I'd prefer not to soil my hands touching JG fittings! Expensive, break if you drop 'em (or marginally over-tighten any with threads - the "Acetal" ones that is), unreliable, bulky ... naff, naff, naff. Just remember there are better systems available especially for gas ... and cheaper. (Try pneumatic tools and parts suppliers).

(What I use are undergoing a bit of a supply issue at the moment, so I make no recommendation).

 

[LeeH]

As above, you can purchase nickel plated brass and stainless fittings but they are metric sizes.

I would t use the nickel plated on the wet side personally.

I personally don’t have issue with the plastic, they are also used in industry. Only incorrect use will cause problems.

I use 3/16 using reducers with no issues.

 

[The-Engineer-That-Brews]

Yes, 3/16" is absolutely fine for CO2. I use 1/4" for all my gas lines.
Pipe size is not an issue because gas flows about a million times easier than beer.
Oxygen ingress is a non-issue for the gas line.
John Guest fittings are fine for me: I've never had one leak and I've dropped them lots without any damage

It really, really doesn't matter whether you come straight out of the regulator at 3/16", or come out at 3/8" and then reduce later on. There's really nothing to choose.

Here's a pic of my regulator setup:

 

[peebee]

... John Guest fittings are fine for me: I've never had one leak and I've dropped them lots without any damage ...

Cheeky so-so.

Showing a picture full of connectors and how many are the fragile JG acetal ones? Let me start counting ... Err? Actually, how many of these are JG?

Even the disconnect in the piccie has had the fragile JG connector replaced with something not JG - why? Possibly 'cos you dropped the disconnect and the JG bit broke off?

Grr.

 

[The-Engineer-That-Brews]

Cheeky so-so.

Showing a picture full of connectors and how many are the fragile JG acetal ones? Let me start counting ... Err? Actually, how many of these are JG?

Even the disconnect in the piccie has had the fragile JG connector replaced with something not JG - why? Possibly 'cos you dropped the disconnect and the JG bit broke off?

Grr.

Ummm that’s a fair comment… The stem adaptor is original JG LoL. You’ll have to believe I use stacks of the beige ones for other stuff. Here are a few of them:

Never had a problem with them, never had one break. Are these the type you’re talking about?

 

[LeeH]

I think his point was that plastic filings fine for most people.