Leaking FV

[TheAmishBrewer]

I am in possession of a 2014 FV produced by a respected North American brewery equipment manufacturer, who I shall not name. This is not a Chinese junk tank.

I am apparently leaking through the thermowell to the outside of the tank. Hold on let me explain, my temp probe is not wet. But beer is coming from behind the the exterior union that holds the temp probe in position... Did I explain that well enough??? Shoulda had a picture huh? The leak seems to come and go.

Here is the point to my post.

Manufacturer wants us to higher a local guy (on their dime) to do the repair, and pull a section off to see if there is leakage into the insulation. Which all makes sense to me.

Anyone out there deal with this before? Any thing I should look out for? Be aware of? Do I need to do a whole new pass wash, or can I just get in and scrub it with some bar keeper?

In another life I made my living as a welder, but I don't feel comfortable doing this myself.

Thanks in advance.

[wailingguitar]

I had a similar issue, also with a North American tank, except leak was coming out from around the Perlick. Just because it is leaking FROM the area where the probe is, doesn't mean that is actually where the leak itself is. I assume we are talking about a double walled tank, the leak could be anywhere above the beer line, traveling down, filling the jacket and finding a spot to exit. Not to be the bearer of bad news, but in a case like this it can be a real needle in a haystack finding the actual leak source.

Once the work is done, I would do a new passivation. You may only have a small area of new welds/polishing, but the little bit of effort could save you some headaches down the road.

[mmussen]

I would definitely go with a full passivisation cycle after the work is done. I've delt with something like that, but it was in a single walled tank and the leak was easy to find. I've heard horror stories about chasing down leaks in an double walled tank. I wish you luck.

[TGTimm]

Once the vessel is empty, pressurize it with air or gas to about 5 psi. Using a stethoscope or something improvised, you may be able to trace the sound of the leak to at least a smaller area. Of course, it's entirely possible that the leak is actually where you think it is, this just seems too easy.

Hire a very good sanitary welder. Someone who fabs dairy, beverage, etc. equipment. It really is worth the the money. We "economized" by hiring a local, highly experienced, certified, and trained welder who was not specifically a sanitary welder. We paid the price, and he felt abused.

Remember your obligation to be sure a contractor is aware of the confined space hazards of working inside of a fermenter. This is a legal obligation.

Like others above have said, you're saving nothing by "spot passivating". Use your CIP system and the amount of chems used won't break the bank (besides, the manufacturer is footing the bill, right?). I'd passivate a vessel if someone spent any amount of time walking/crawling around with gritty boots/shoes. Cheap insurance.

[dick murton]

I have been b.....cked up hill and down dale for pressurising a leaking tank with gas. NEVER pressurise a leaking tank with gas, even at low pressures like this as if the tank were to split (and I accept this is probably not going to happen, but a hairline crack may rapidly spread from a pinhole leak) it would be fairly explosive. If you fill with water and pressurise with water, for some reason it is not as bad. And this is the judgement of the guys who make and others who insure tanks.

So pressurise by all means, but do it with water - coloured with something to make it easier to spot. Far less dangerous.

[TiminOz]

Are you leaking beer or glycol? If it is glycol you should be losing a small amount from the weep hole at the bottom of the cone. If your leaking beer you have an even bigger problem and if beer is getting into the insulation it too should eventually leak out the weep hole.

[wailingguitar]

I have been b.....cked up hill and down dale for pressurising a leaking tank with gas. NEVER pressurise a leaking tank with gas, even at low pressures like this as if the tank were to split (and I accept this is probably not going to happen, but a hairline crack may rapidly spread from a pinhole leak) it would be fairly explosive. If you fill with water and pressurise with water, for some reason it is not as bad. And this is the judgement of the guys who make and others who insure tanks.

So pressurise by all means, but do it with water - coloured with something to make it easier to spot. Far less dangerous.

Ditto this! Tank pressurized with gas = deadly in the wrong circumstances

[TheAmishBrewer]

Thanks guys

Thanks for all the help so far. I knew I would get some ideas I hadn't thought of here.

I Just filled this tank again today, I am in start up phase.
I hope after today I can take this tank off line for a day or two investigate further. I am told by the owners that a welder is still a few weeks out.

This is mostly a bump post to get some more ideas. I will keep this thread updated. Hopefully it helps some one else later.

[TL Services]

In your original post, you mentioned that the leak seems to come and go - this may not be the easiest 'hindsight' question, but is there any connection between leaking and fill level at the time?

If so, that might give you a steer on where the leak might be...if the info's not available, follow dick murton's advice of filling with coloured water, but do it in stages.

At least that way you can narrow down the approximate band where the fault lies, then drain down and use your own experience as a welder to take a look.

[Matt Dog]

It does make some sense that the leak is right at the probe, if it was at any point that is jacketed the beer would leak into the glycol jacket or more likely glycol would leak into the tank. Since the probe is manufactured to pass all the way through the jacket and into the tank you could have a hairline crack that comes and goes because under different pressure or temp it widens just enough to allow beer to pass through. If beer were leaking from inside the tank into the insulation it should eventually come out the weephole at the bottom of the tank. I had a welder come in once who sprayed some type of leak detect on the tank and also used some small electrical device that appeared to shoot a current at the hairline cracks and open them just enough to be seen. That was years ago but he did find my problem on my kettle and fix it.