John Guest PTC - is there a MTBF I don't know about?

[balrog]

Mean time between failure
Duty cycle

How many times can I push to connect, remove to clean, change tube, change my mind, alter tube length, etc?

I ask because i've now had two John Guest fittings break - a quarter of the collar, springy, clampy inner flangeity thingy go breaky break.

Perhaps they are made to install in a @day_trippr keezer of all keezers, dunk leak test, and stay installed for all of time?
(Side question: why no pictures of dunk testing a 21.7 cu ft chest freezer?)

 

[day_trippr]

I don't think I've seen that failure mode posted before on hbt, and certainly haven't experienced it.
Are you using any chemicals on those fittings for cleaning or sanitation?

Cheers!

 

[T Murph]

@balro I have no experience with John Guest PTC so I have no advise regarding that product. However I do have experience with Shark Bite fittings. I use them both in my brewery set up and in multiple home water lines both personal and as professional. So far, knock on wood, I never had one fail. I us them on my imersion wort chiller and Spike conical coil cooler. Those are the ones that get connected and disconnected most often.
They work out well for me. It may be something worth checking out for you.

 

[Deadalus]

I had one out of four break exactly like that. It was however a Duotight. It was on a relatively new installation, I had run at most two kegs through it and doubt I did anything to it but push the tubing in the first time and that was it. I had not cleaned it at all. And damnit I ordered John Guest replacements because I wasn't impressed! (I did order three pieces though just in case.)

 

[Deadalus]

There's a ring of square teeth on the inside of the main fitting body but on the one that broke on mine, 3 out of 12 teeth are rounded and not full length. I would say "worn down" but I suspect that however these are made, those teeth weren't fully formed to begin with. The collet spins so I can't say with any certainty that the rounded teeth caused the failure.

 

[Deadalus]

In this post on another thread, Duotight says the teeth on the collet are stainless steel. I bought my fittings from Morebeer on 12/20/2020. Maybe Duotight changed the materials knowing that's a failure point.

Nevermind, the "teeth" they are referring to are embedded perpendicular to the end tab (head) of the collet. They are hard to see but visible in the first picture I posted. Mine didn't break at the stainless steel. They broke a little bit lower, it doesn't appear that the boundary between the stainless and plastic caused the failure.

 

[McMullan]

Looks like chemical fracturing to me. Too long in sanitiser? That can make the fitting, especially collet teeth, brittle then fail. I've had this happen once or twice.

 

[balrog]

StarSan rinsing all the time. Use a fitting to xfr beer, rinse by running water then starsan through it, disassemble, shake out excess, toss on the drying rack/bin/towel/container. Point being, it doesn't sit immersed for days or weeks on end.

Will keep eye and closely inspect the rest of the 10 that came in the bag, and my kanban spidey sense says I should order another. Or the sharkbite. Or Duotight. Makes me wonder about the 4 Kegland quick disconnects with built in PTC I just got to try out...

 

[T Murph]

I reviewed some older post yesterday after reading these post. While I've had good luck with Sharkbites, I'm gonna start buying Duotights moving forward. Duotight employs two O rings that help ensure a good seal. And after looking at them from Morebeer and Kegland, they are about half the cost of sharkbites.

 

[McMullan]

To be honest, duotight fittings aren't as good quality as JG fittings. I go with duotight when they offer something I can"t get anywhere else. Here's a duotight fitting over exposed to starsan solution:

 

[T Murph]

Dammit man. Right when I thought about changing. Guess I'll stick with sharkbites.

 

[McMullan]

Dammit man. Right when I thought about changing. Guess I'll stick with sharkbites.

Don't let me put you off duotight fittings, I have quite a few now and none have failed in use, to be fair. They just seem to be lesser quality when compared directly with something like JG.

 

[Control Freak]

I'm not sure that Guest fittings are designed for repeated release but these fittings are. I worked with them for years without a failure in an industrial setting.
https://pmcstone.com/airfittings/10mm/