Problems with gas manifold

[BlackRegent]

This one is for our resident hand pull experts or anyone who uses a gas manifold.

I have 4 hand pumps with 4 kegs on at the same time. I feed the CO2 into a low pressure gas regulator (the Clesse regulator recommended by @peebee) which then runs into a 4 way manifold. I had my dark mild connected to the last of the 4 outlets on the gas manifold. I thought it was getting increasingly flat and lifeless and was developing a bit of an off taste (which was a shame as it was bloody lovely to begin with). I then forgot about it for a bit. On going back to it today and doing some investigation, I realise that the manifold just wasn’t feeding gas to the keg, to the point that it has lost pressure completely and let air in. The keg is now largely ruined with a definite cidery taste. I did some investigation and discovered you had to significantly up the pressure (around 5-10 psi) before it let gas pass and even then it made a sort of rasping sound, like air being released from a balloon when you pinch the end.

I dont know what’s going on but it means I no longer trust the manifold and I’ve disconnected it completely and topped up the pressure on each keg.

Has anyone had a similar experience of using a manifold at low pressure or generally? Is there a solution? I may just resort to binning the manifold and using t pieces to split the line as I can’t take the chance of spoiling more kegs. I’m upset enough as it is that I seem to have lost most of a batch. I thought those days were behind me after moving to kegs!

 

[peebee]

It sounds like your manifold has non-return valves fitted to each outlet port, and it is one of these valves that is faulty. Such valves prevent all the kegs sharing the same gas space (and any bugs one might contain) which is what you will have if you replace the manifold with line splitters. The valves are often part of the gas tap for that line at the manifold.

So you might be able to isolate, check, replace (or repair) the faulty valve. Not replace the entire manifold.

Difficult to say for sure without actually seeing the manifold.

 

[BlackRegent]

As a follow up to this (and in case anybody else tries to research a similar problem in the future) through returning to the original AliExpress listing I discovered that these manifolds suffer a loss of pressure of 2psi between the inlet and outlet due to the check valve. The manufacturer recommends setting the regulator to 2psi higher than the desired keg pressure. That suggests an input of 2psi will struggle to pass through the check valve, or at the very least there will be little to no output. Since the max output of the Clesse LPG regulator is c 2psi, I have removed it from the system and set the primary regulator to c 5psi.

 

[BarnBrian]

I would have thought that your primary regulator needs to be set much higher, 20 psi or more, I'm sure peebee will have the answer.

 

[BlackRegent]

@BarnBrian

The gas line is going straight from the regulator to the manifold. If I set the regulator to 20psi I will have very fizzy cask ale!

 

[BarnBrian]

@BarnBrian

The gas line is going straight from the regulator to the manifold. If I set the regulator to 20psi I will have very fizzy cask ale!

I thought you had the secondary regulator set at less than 2psi or am I missing something.

 

[BlackRegent]

Originally, the primary went into a secondary (a Clesse LPG regulator) which then went into the manifold. Because the Clesse regulator has a low output (a max of c. 2psi) it seems that its output is too low to pass through the check valves on the manifold. I've therefore removed the secondary (i.e. the Clesse) so I just have a primary regulator, which I've set to c 5psi in the expectation it will be stepped down to c.3 psi by the check valves on the manifold outputs. Not an ideal solution as it lacks accuracy, but the best I can do without inserting secondary regulators on each output of the manifold.

 

[marshbrewer]

I was going to say - I would put a secondary reg on each manifold output; but then I use adjustable secondary regulators so I can have different pressures on each keg.

 

[BlackRegent]

@jjsh
What secondary regulators do you use? The Kegland Duotight ones seem to be out of stock everywhere (even on AliExpress)

 

[marshbrewer]

I use Shako NR200's.

 

[peebee]

As a follow up to this (and in case anybody else tries to research a similar problem in the future) through returning to the original AliExpress listing I discovered that these manifolds suffer a loss of pressure of 2psi between the inlet and outlet due to the check valve. The manufacturer recommends setting the regulator to 2psi higher than the desired keg pressure. That suggests an input of 2psi will struggle to pass through the check valve, or at the very least there will be little to no output. Since the max output of the Clesse LPG regulator is c 2psi, I have removed it from the system and set the primary regulator to c 5psi.

What seems to be described is a check valve with a 2PSI "cracking pressure". That's quite high! The "cracking pressure" is the pressure needed for the valve to open so if you had a Clesse 75-150mbar LPG regulator upstream it would have to be used on full (150mbar = 2.15PSI) to have any chance of working, and as you have found "cracking pressures" are not usually very precise and you may be looking at something between 1.5 and 2.5PSI and subject to plenty of variability.

Solution1: Replace the manifold with one that has finer check-valves.

Solution2: Preferred but you won't like it! Set the primary to full output (often 4BAR or 60PSI), actually you can get way with less, say 2BAR. The Clesse LPG regulators can handle an input of 16 BAR, some secondary regulators should be subject to no more than 10BAR. And then the bit you won't like ... fit each output from the manifold with its own LPG regulator.

 

[Davegase]

@jjsh
What secondary regulators do you use? The Kegland Duotight ones seem to be out of stock everywhere (even on AliExpress)

I've just looked at AliExpress and scene in the kegland duo types with integrated gauge for £12.04 plus 25 pence shipping to United Kingdom, and it says 998 available.

 

[peebee]

I've just looked at AliExpress and scene in the kegland duo types with integrated gauge for £12.04 plus 25 pence shipping to United Kingdom, and it says 998 available.

The Shako's that @jjsh posted are miles better, and perhaps cheaper (the gauge is an addon but filthy cheap)*. But these styles of regulator are not suitable for holding pressures of 1-2PSI: You must go for the LPG regulators to do that (extra large diaphragms to make them sensitive enough), and the Clesse ones are the best I've come across.

*EDIT: The "L2" variant is best as it operates in the lower pressures (<30PSI). They also vent quite precisely: I use them as "spunding" valves too!

 

[TomB88]

Can one not remove the check valve/s from the manifold? I am waiting for my manifold to arrive so can't see how they are put together, but would assume it is a similar setup to the poppet on a keg...

Might be worth checking.

 

[peebee]

Can one not remove the check valve/s from the manifold? I am waiting for my manifold to arrive so can't see how they are put together, but would assume it is a similar setup to the poppet on a keg...

Might be worth checking.

... Such valves prevent all the kegs sharing the same gas space (and any bugs one might contain) ...

 

[BlackRegent]

Can one not remove the check valve/s from the manifold? I am waiting for my manifold to arrive so can't see how they are put together, but would assume it is a similar setup to the poppet on a keg...

Might be worth checking.

I unscrewed the output valve from the manifold (which takes some doing as they're tight) and they appear to be sealed units to my untrained eye.

There is also the shared headspace problem that peebee identified.

I've ordered some more of the Clesse regulators and I'm going to put together a proper gas board with regulators on each output and put a spare Kegland regulator I have on the fifth output for the rare occasion I will need higher pressure.

 

[TomB88]

Peebee, noted. Easily solved by the addition of JG or similar check valves on each line - unless I'm missing something?

Sounds like BlackRegent has it sorted now so all good.

ATB,

Tom

 

[peebee]

Peebee, noted. Easily solved by the addition of JG or similar check valves on each line - unless I'm missing something?

Sounds like BlackRegent has it sorted now so all good.

ATB,

Tom

Yeap, @BlackRegent is sorted. I'll just point out those JG check-valves are a hell of a price, but as this is gas and not liquid something cheaper should be available. Then faced with disabling the manifold's check-valves which the earlier post suggest isn't easy/possible.

That's the trouble with trying to seek out the cheapest solution, you end up with loads of "cheap" stuff that you didn't need. I've got loads!