Pressure transfer mystery!

[Seghes]

I am attempting to do a pressure transfer from Fermzilla FV to corny keg and have hit a problem I cannot fathom - I cannot achieve flow
- FV is set at 5psi, keg at zero psi with psv left open (I also tried a 10-2 psi ratio (FV-keg - heaven knows why)
- Dip tube is attached to float and filter, ensuring the filter and tube are below the surface, ie. no air/co2 being sucked in. I’ve taken it all apart to ensure no blockage (yes my oxygen free set up temporarily abandoned)
- I have double checked the whole assembly including swapping over liquid disconnects, in case one was blocked (surely they’re not both faulty)
- I’ve tried a party beer tap attached to FV - that didn’t work either
Something is going wrong from the submerged dip tube to the liquid disconnect on the FV. Is there a law of physics at play here that I don’t know about….?

 

[xozzx]

Try blasting a small amount of CO2 down the liquid disconnect of the FV, this will remove any blockage.

Obviously the pressure of the CO2 you add will need to be higher than the pressure the FV is set to so that CO2 can flow down.

 

[Seghes]

Try blasting a small amount of CO2 down the liquid disconnect of the FV, this will remove any blockage.

Obviously the pressure of the CO2 you add will need to be higher than the pressure the FV is set to so that CO2 can flow down.

Thanks tried that - didn’t work

 

[xozzx]

Thanks tried that - didn’t work

Didnt work as in no CO2 went into the FV or that it didnt solve the issue? If no CO2 going in then it is definitely a blockage.

Is the fermzilla definitely pressurised? If you squeeze it is it solid?

 

[Seghes]

CO2 blasted in to FV no problem. FV is definitely pressurised as I can test with quick release of its psv

 

[xozzx]

ok, strange as this would suggest no blockage in the FV dip tube. Try connecting liquid disconnect to the liquid out with just some open ended pipe into a jar. Be ready to disconnect it quickly if beer starts spraying out. If you dont get anything then try pushing the ball lock in with a small screwdriver etc and see if beer sprays out.

Is your disconnect a standard one - no fancy check valve or anything like that?

Could you post some pics of the setup?

 

[Seghes]

Try connecting liquid disconnect to the liquid out with just some open ended pipe into a jar.

No, nothing

try pushing the ball lock in with a small screwdriver etc and see if beer sprays out

Nothing, the tube from FV liquid post is empty

Is your disconnect a standard one - no fancy check valve or anything like that?

standard one.


The more I look at this, the more I see the problem is that no beer is entering the dip tube from the the FV to the underside of the FV liquid post. The tube looks like it has no liquid in so it’s not getting up to the liquid disconnect. Just to confuse things, after about a 3rd gas blow down the FV liquid post it worked for a couple of litres then filled with co2 and stopped. More blows down the liquid post didn’t start it again.
See photo for detail of the set up

 

[RichardM]

If the fermenter is pressurised, the dip tube is below the level of the beer, the liquid out post is ok and the line from the liquid out post is ok then the dip tube, or filter on the end of it must be blocked.

 

[tondy79]

Are you getting co2 released from the liquid post, or nothing at all?

 

[Buffers brewery]

You might have an airlock (gas lock) in the tube, i.e. a bit of liquid then gas then liquid. If you can pump some fresh cold water through your beer line into the fv to bleed it of any gas.

 

[Seghes]

If the fermenter is pressurised, the dip tube is below the level of the beer, the liquid out post is ok and the line from the liquid out post is ok then the dip tube, or filter on the end of it must be blocked.

I absolutely agree - but I’ve had the dip tube out several times and cleaned, checked, cursed it and reassembled.

 

[Seghes]

Are you getting co2 released from the liquid post, or nothing at all?

Nothing

 

[Seghes]

You might have an airlock (gas lock) in the tube, i.e. a bit of liquid then gas then liquid. If you can pump some fresh cold water through your beer line into the fv to bleed it of any gas.

Def worth a try, but sadly didn’t work

 

[Buffers brewery]

Have you tried removing the quick connect from the keg end of the beer line and running beer into a jug?

 

[Seghes]

Have you tried removing the quick connect from the keg end of the beer line and running beer into a jug?

Yes, the problem seems to be with the dip tube. It’s just not running up the tube from the float/filter end. An airlock or something would make sense, but I’m damned if I can solve it.

 

[Buffers brewery]

Take the filter off?

 

[xozzx]

Sounds like the dip tube may be getting a kink and blocking flow. Do you have any spare? Could you cut it shorter?

 

[The-Engineer-That-Brews]

At least the vessel is transparent so you have at least some chance to see what might be going on.
I see that (if I understand correctly) you were at least initially able to blast some CO2 in to the FV through the beer-out post; and that you have verified the FV is pressurised by pulling the PRV.

That’s very odd! I think if I were in your shoes my next move would be to suck on the beer line (being ready to pull the disconnect off sharpish if it suddenly starts flowing!). If it’s a kinked pipe or similar then I should think you’d get a teeny bit of flow, but if you’re getting nowt at all then I’d start to suspect the disconnect.

Just a thought, can you check the disconnect on a pressurised keg with some water in it or something, just to check it works?

 

[RichardM]

At least the vessel is transparent so you have at least some chance to see what might be going on.
I see that (if I understand correctly) you were at least initially able to blast some CO2 in to the FV through the beer-out post; and that you have verified the FV is pressurised by pulling the PRV.

That’s very odd! I think if I were in your shoes my next move would be to suck on the beer line (being ready to pull the disconnect off sharpish if it suddenly starts flowing!). If it’s a kinked pipe or similar then I should think you’d get a teeny bit of flow, but if you’re getting nowt at all then I’d start to suspect the disconnect.

Just a thought, can you check the disconnect on a pressurised keg with some water in it or something, just to check it works?

The OP has swapped the disconnect for a second one, so unless he has two faulty disconnects it's not that.

 

[Mash Monster]

I’ve just had a similar experience with a keg in my kegerator. First off the beer line to the tap came off the shank disconnect and I lost several litres. Then connected back up nothing would come out of the tap.Did all the things suggested above ie. Changing disconnects and blowing CO2 through the pipe still nothing eventually I sucked on the pipe and a minute amount of hop debris came out and it ran clear and all appears OK.
It sounds to me like the OP may have debris in the filter /dip tube that is being partially blown out by the burst of CO2 but being sucked back up causing the blockage when trying to perform the transfer.