Help understanding a possible gas leak in DIY kegerator

[Chicoquente]

Hi everyone. I am new to the forums and discovered it while trying to figure out the issue with a DIY kegerator I built last month. I was totally new to this and it only came about because we ended up with a mini fridge we no longer needed and since my wife works at a brewery it seemed like a good use for it. I pieced together my own setup as I needed a low profile coupler and could not find a kit with one included. I'm going to provide as much detail as I can as I am inexperienced with this issue and figure the more I can provide the better.

The kegerator was first tapped around June 22 and everything was great for us. We use a slim quarter keg so 7.75gal/29L (we're Canadian!). We have a 5Lb CO2 tank. Right around the 4 week mark I went to pour a beer and on first sip thought it tasted off. It took me a bit to think about it and then I looked at the regulator and it showed my tank as empty. I thought that was odd as my early research combined with speaking to a coworker with a kegerator led me to believe I should get anywhere from 2-2.5 slim quarter kegs from a 5Lb tank., and yet we had not even finished our first slim quarter. From lifting the keg I would guess it's around 1/3 full at this point. At this point I uncoupled the the keg, disconnected the gas line from the coupler and remove the CO2 tank, hose and regulator.

I had the CO2 refilled and then sat down to find the leak. I left the CO2 tank sitting on my work bench a few days to see if anything changed. After a few days it still felt the same so I figured the tank itself was good. I then installed the regulator with no hose attached, shut off turned off and opened the tank valve. I set the pressure to around 4PSI and sprayed soapy water all over the tank handle, regulator nut and regulator. I could not locate any sign of bubbles forming. I cleaned up and reattached the gas line to the regulator using yellow Teflon on the threads. At the keg coupler I cut off the end of my gas line just in case the pipe clamp had damaged it the first time and reconnected the line. I coupled back to the keg and sprayed the soapy water all over the coupler and gas line connection and again I saw no signs of bubbles forming.

I assumed that perhaps I have fixed whatever caused the leak at this point and put everything back in to service. I enjoyed a pint and thought all was well. 2 days later before heading to the cottage for awhile I decided I would close off the CO2 tank just in case there was still a leak. To my disappointment I noticed the left gauge on my regulator showed somewhere between the red and green section. I was in a rush to get going so I didn't take notice of the exact measurement and just shut the tank, disconnected the regulator and left.

At this point I don't know how to proceed. The CO2 isn't cheap as it costs me around $25 to fill it here in Canada so I am not eager to just keep trying and then finding out I've drained an entire tank in no time. I'm already $50 of CO2 in to my first keg and at a total loss as to what to do. Last night I put the regulator back on the tank and opened the valve on tank (shut off still closed and no gas line connected) and the left valve has been sitting in the green around 64 (PSI?) so it seems like it says it is good. Is it normal that the number drops down significantly while it is connected to the system and climbs back up once it is closed off to the keg?

Am I correct in my assumption that my leak should be somewhere from CO2 tank to the coupler as I have no signs of leaked beer from keg to faucet? My assumption was that if I was losing gas between the coupler and faucet I would also have a mess of beer to clean up which is why I have not checked any of that part of the system.

What would be my next steps? I Should note I have never once heard the sound of a leak which is why I never noticed it before the first tank went empty. I keep my glasses in the fridge so it is open almost daily and I would probably notice the sound of a leak. I am really hoping to proceed with further troubleshooting that doesn't just result in me draining lots more $25 CO2 tanks. Is there anything else I can use or do to troubleshoot? Where else should I be checking? Should I try to spray test again but bump the output pressure higher than the 4PSI I used last time (based on some articles I read on troubleshooting). Would higher PSI make the bubbles more likely to be seen?

Any advice would be highly appreciated by this rookie. Sorry again if I have gone too far or too little on the information. I am very eager to get this resolved so any advice for you guys will be greatly appreciated!

My material list:
Taprite Sanke "D" Low Profile Coupler (FT44T)
Taprite Primary CO2 Regulator (T742HP-02)
Nukatap Stainless Steel FC Beer Faucet
Stainless Steel Beer Shank
Gas Tubing
Tubing Assembly
5Lb CO2 Tank

 

[Golddiggie]

If you're using worm clamps (the ones you can tighten and loosen, ditch them for oetiker clamps. Yes, you'll need to get a crimping tool and the clamps are one use items. BUT they seal 100% (full 360 degrees around the tubing/fitting) without any chance for leak (provided you use the correct size for the tubing OD).

Testing at 4psi for leaks isn't going to get them to show. Use at least 10psi for the testing pressure. 15-20psi would be better to get leaks to show up.

Since you're using a MFL fitting on the regulator (gas outlet) are you using the plastic flare fitting washers at each of those? Any time you have a metal to metal connection, you need one of those. The plastic ball lock QD's with the MFL fittings on them don't require the washers, since they have ones built in (basically, due to the plastic on the end of the MFL threads).

I didn't see if you have the CO2 tank (and such) inside the fridge or outside of it. I always put my CO2/beer gas tanks outside where the kegs are (either fridge or keezer). It means you can more readily check the pressure levels as well as adjust them as needed.

 

[day_trippr]

fwiw, the cylinder coupler stem on that Taprite regulator uses a "quad seal" O-ring that can be easily damaged and be the source of significant leakage.
I didn't trust mine on its own so I've always included a standard fiber washer...

Cheers!

 

[Chicoquente]

@Golddiggie - Thanks. Tonight I will hopefully get a chance to reassemble and test at a higher PSI. Is my previous assumption correct that because there is no indication of liquid leakage anywhere that my issue is between the CO2 Tank and the Sanke coupler?

For now I will have no choice but to continue using the worm clamp however I will definitely look in to the oetiker clamps, with any luck I can find someone in my neighbourhood to borrow a crimper from.

I believe I have the plastic flare fitting washers install but just to be sure I am including some photos of my gas connections to verify.

@day_trippr Thanks for the tip. Are you talking about something like this?


What is this label telling me? Is this saying I can't add a washer as per @day_trippr 's advice?


There is no washer/o-ring/etc inside the nut itself. Should there be ?

I could have sworn this connection had a little white fitting inside that could pop out but this time it is not. Maybe I am mixing it up, OR in my hasty rush I dropped it on my quick disconnect before leaving the for the cottage and need to locate it. There is a plastic at the bottom of the connector though but seems to remain in place. Would this be the only seal that should be here or did I lose something? Additionally are these nylon ones good or is there a better seal to use?

 

[Golddiggie]

Before you do anything more to test your setup, get these: Flare Fitting - Washer | MoreBeer
You should be able to get them from your local HBS, since they're a very common item. Metal on metal WILL leak.

For the regulator to keg coupling, get at least one of the fiber washers already mentioned: Regulator Gasket | MoreBeer
I use the plastic version of that on my regulator to tank connections. With how mashed up the o-ring looks on your regulator, I'd either replace it and/or get one of the washers to go between as well. That could be another leak source.

 

[day_trippr]

^Agreed^ The cylinder fiber or plastic washer is what I was referring to and I highly recommend because the captive quad-seal ring has been the cause of lost gas for lots of folks as related on the HBT forums.

And, yes, you definitely are missing a "fish eye" flare washer between that gas line and your regulator shutoff valve. They look like this - and do tend to fall out and get lost.

Attend to those two obvious issues and I bet you'll hold onto your CO2 a lot longer

Cheers!

 

[Chicoquente]

Thanks guys. I'll make a point of getting those items. Quick question about sizing. From the link to the gas line I purchased it says it uses a 5/16" swivel nut. Am I correct in assuming I require a 5/16" fish eye flare washer? I only ask because I am having a hard time locating one so far near me and the vast majority of listings are 1/4" which I assume would be incorrect to use?

I am also having a hard time determining the proper size of the fiber washer as I can't seem to find the size specs on that. However I have found 2 options listed for Taprite CO2 regulator which I am guessing would be the correct ones? The first is Taprite Fiber Washer and the second is Taprite Delrin Washer. Any advantage to either? Which would you recommend?

EDIT: @Golddiggie As for the Oetiker clamp. How does one properly size that? The hose I have is 5/16" which is 14.2875mm. I see listings for 14.0mm and 14.5mm. Is this a round up or round down kind of situation?

 

[Golddiggie]

Size the Oetiker clamps that have the OD of your tubing in their range. They are listed by the largest size they open to (stamped on them). I use the 15.7 (stamped) on my 5/16" ID, 9/16" OD gas lines. The 13.3 are on my 3/16" ID beer lines.
Amazon link for the clamps: Amazon.com
The crimp tool I use most often is a ratcheting model that can crimp from two different positions (side or end of tool). I have a couple of regular crimping tools where one of those has that feature as well. The others are just end crimping.
I also use good diagonal cutters (heavy duty) to remove the clamps. These work really well. Amazon.com

I use these washers at the regulator/CO2 tank connection: Regulator Washer

 

[day_trippr]

fwiw, I've used both the plastic and the fiber style regulator washers with no issues.
Many gas suppliers will stock items like that - no need to pay Taprite money...

Cheers!

 

[Chicoquente]

Thank you to both of you. I hope to get my supplies in the next week days and ideally do all my fixes this weekend and see where we are at. I appreciate all of your advice.

 

[Quentin Nelson]

Hi Chico, Your lost-CO2 problem is very common & all the suggestions above are good. Could also be at gas-in fitting on your version of an American Cornelius keg. Oetiker clamps are cool & I have them, but usually just use high quality automotive screw clamps, no problems. I like thick-wall 3/16" ID see-thru beer line for CO2 use also. It's a bugger to get on to 1/4" metal fittings (hot water) but never leaks.

I taught an Advanced Home Brewing Class pre-COVID & got the "lost my expensive CO2 overnight" question many times. That's ONE reason I personally like refilling small PAINTBALL TANKS, even as small as 9-12 oz. One 9oz will just about dispense a 5 gallon corny. Takes a bit more to carbonate 5 gal. BUT YOU WILL NEVER LOSE MORE THAN THAT MUCH CO2 while you are finding your leak. You shouldn't need any teflon tape on any reg or corny fittings except on NPT tapered threads (like T's & adaptors). A paintball tank ADAPTOR with regular CGA 320 male threads screws right into your CO2 reg. Fits in the fridge easily, hangs on a corny to go to a party without weighing 25-40lb. Not too expensive to buy or build a "refill station". Put the little PB tank in the freezer for an hour before filling from upside-down CO2 tank (or one with a syphon tube that goes to liquid gas on the bottom). Lots of youtube videos & the Homebrew stores or Amazon sell all the stuff reasonable.

 

[JAReeves]

fwiw, the cylinder coupler stem on that Taprite regulator uses a "quad seal" O-ring that can be easily damaged and be the source of significant leakage.
I didn't trust mine on its own so I've always included a standard fiber washer...

Cheers!

FWIW I had a leak at the tank-regulator connection and I keg-lubed a leftover Ball-Lock O-Ring into place as an extra seal. Been good for over a year, but I do check for leaks every time I switch tanks. I also got a bum-seal on a propane tank at The Big Orange Home Improvement Store, used the same method and it worked great. Of course, CO2 doesn't go boom if there's a leak....

 

[Golddiggie]

Using paintball takes gets expensive FAST! The places that fill them in my area do NOT swap them out, simply fill them as you wait. So, every 5 years you end up needing to buy new ones. I use these ONLY to dispense from a keg when remote. I also use the smaller regulators on them since I don't want to have a regulator that weighs MORE than the CO2 bottle tip over and do something bad (like breaking). One of the two regulators (for CO2) I have has the bracket to hook onto the keg handle. The other (for nitrogen) doesn't... Yet at least. I actually need to get the paintball CO2 bottle that I have refilled for when I take my smaller keg to gatherings. I might pick up a larger one (have a 20oz size now) since they don't last nearly as long as you want them to. I use them a lot for sealing kegs after I've cleaned and sanitized them. It's easier to have that setup in the kitchen area than need to bring one of my other CO2 tanks up from the basement (where I ferment and transfer into kegs/can).

Maybe if you only have one keg to deal with, carbonating/serving with these would be "OK". But, even then, I think it's a stretch. Make your system solid and you will have zero issues. Put the washers between the swivel nuts and MFL fittings and that's another leak source eliminated. Change those EVERY TIME you remove the swivel nut from whatever it's connecting to. These are sacrificial items and will not properly seal if you try to use them a second time.

As for the automotive worm clamps... I avoid ALL worm clamps like the plague. Sure, you MIGHT get one to seal right, but the amount of frustration I've had EVERY time I've tried to use one makes me avoid them at all costs. Never had a single oetiker clamp NOT seal fully on me. IMO/IME, well worth getting the crimping tool and a supply of the clamps. McMaster sells them in 25 count bags. Amazon has them in 100 count bag. These are also stainless steel (avoid any that are NOT stainless steel).

BTW, I usually buy the washers for swivel nuts in larger amounts when I'm ordering them. I think I have at least 20-30 on hand right now. Just means anytime I want to change over any of my beer, or gas, lines I don't need to worry about not having them. When I start getting low, I simply add them to the cart of whatever vendor I'm ordering from (with free shipping) so that it's no issue.

 

[Chicoquente]

I replaced every seal/oring and used keg lube on the o-rings. As well I replaced the worm clamp with an oetiker clamp. I did in fact buy extras on everything to have on hand. I completely agree these are better to have on hand since they are cheap as opposed to needing them and not having.

After all of that I reconnected the system and sprayed soapy water everywhere. I have not found any sign of bubbles at all at 10psi. The high pressure gauge was reading between 1100-1200psi when I connected to the regulator and opened the shut offs last night. I had a beer and all seemed well. This morning I went for a quick look at that same gauge which is now around 600psi. Is this normal? Or does that indicate I have in fact lost half a tank of gas already? If it matters the slim quarter keg is approximately 1/3 full, maybe a little less. Should I be concerned or is that gauge just not something to rely on?

I should note that I didn’t determine the initial leak (when I started this thread) based on just that gauge, I went for a beer and it clearly had no CO2.

 

[Tallgrass]

Tank pressure is temperature dependent until you get really low. What you're describing could be possible if you the 1100 psi was when the tank was hot and 600 psi at room temp. My half full tank is about 700 psi at 72f. The only way to really know is to weigh the tank. The tare weight of the tank is stamped somewhere around the neck.

The rubber Taprite seal has always been a problem for me. I removed it and replaced with a new fiber washer and Teflon tape on tank threads every change. Maybe not ideal but I get bubbles with the leak detection if I do it any other way.

 

[Golddiggie]

Did you remove the gas line from your keg(s) after closing the tank?? If you're pressure testing the system, you need to remove the kegs from it to make sure that's not why the pressure dropped.