Advice for check valve with beer engine

[hoppy hannis]

Hi everyone,

I've set up a hand pump with the RLBS demand valve. I have gas pressure set to 150mbar using a propane regulator so really low pressure. Problem is, I can't serve beer unless I prime the pump first with water. I have a drain valve so the at the end of a session I can leave the line clear, but once the line is clear I can't seem to pull beer through the demand valve without pouring water into the lines through the drain valve in order to prime the beer engine. Anyone got an idea what the solution might be?

 

[AnimatedGIF]

That sounds annoying. I wonder if that's the same reason I am getting foam in the line on mine.
Sounds like our setup is identical, except for the drain valve, which I didn't include.

 

[AnimatedGIF]

Thinking about it, I know it sounds obvious, but have you left the drain valve open by mistake? I imagine that would just draw air through.

 

[hoppy hannis]

I thought about that and checked. Drain valve definitely shut and all seals definitely sealed. Ive been over it a few times now, its driving me mad!

 

[AnimatedGIF]

its driving me mad!

I bet! Thi foam in the beer lines is driving me rather potty. Hoping somon co.es forwrd ith n ide for you.

 

[Dilettante Brewing]

I have the same set up but without the low pressure propane regulator and I have no issues. So assuming the demand valve is working correctly what happens if you take out the regulator? Eg if you just draw in line cleaner out of a jug or connect it to a BIAB so no pressure needed.

 

[peebee]

The hand-pump creates suction and will happily pull air past Corny keg seals or collapse plastic pressure barrels if sealed (and no gas regulator), so it is a bit of a mystery.

I was going to ask why you emptied the beer lines between sessions (it doesn't empty the pump's cylinder as that has a one-way "flapper" valve) and it occurred to me: You don't use silicone tubes to the pump do you? (They collapse and seal shut when empty and subject to a partial vacuum).

 

[peebee]

... Hoping somon co.es forwrd ith n ide for you.

Does the foam cause keyboard malfunction too?

But foam will occur if the beer (not just the space above the beer) hasn't vented properly. But that should rectify itself after a few days. The restrictions the beer has to pass getting out of the keg (e.g. like in disconnect posts) or through the demand valve will cause over carbonated beer to "degas" and create foam (the pump itself forces a lot of degassing due to turbulence, but you see the foam in the feed pipes). Finally; tiny "leaks" anywhere in the feed pipe (including any dip-tube inside the keg) may allow air (CO2 if inside the keg) to be drawn in when the pump is operated.

 

[AnimatedGIF]

Does the foam cause keyboard malfunction too?

But foam will occur if the beer (not just the space above the beer) hasn't vented properly. But that should rectify itself after a few days. The restrictions the beer has to pass getting out of the keg (e.g. like in disconnect posts) or through the demand valve will cause over carbonated beer to "degas" and create foam (the pump itself forces a lot of degassing due to turbulence, but you see the foam in the feed pipes). Finally; tiny "leaks" anywhere in the feed pipe (including any dip-tube inside the keg) may allow air (CO2 if inside the keg) to be drawn in when the pump is operated.

I think it was beer and tiredness that caused the keyboard malfunction
Thanks for that. I think it is more than likely the lack of venting, as I initially carbed up the beer before I had the engine set up, so qas more carbed than required.

 

[peebee]

... it doesn't empty the pump's cylinder as that has a one-way "flapper" valve ...

In one of those "coincident" moments: I'm immediately reminded how "flapper" valves work. I'm cleaning my "spare" hand pump (retained for ad-hoc "field" installations) and the blasted thing wont pump a drop of water! After much cursing I look at what I've arranged. The pump is clamped to a workmate. Silicone tubes (in & out) dip into a bucket of water. For reasons that don't come to mind, it's up-side-down. Ahh ...

"Flapper" valves are very simple affairs and rely on gravity to close them. My flappers were the wrong way up and therefore open. Tip pump upright and hey-presto, I can continue cleaning it.

 

[hoppy hannis]

I checked today and more of a mystery. I tried putting water in Infront of the demand valve (so bypassing it) and the pump won't suck it through. It's almost like I have to feed water to the pump to generate enough of a vacuum to pull any liquid through the lines at the demand valve

@peebee No silicone hose in my setup, and I have the drain set up so it does empty the beer engine, there's definitely nothing left in it after I open the drain tap

Edit: just tried taking the whole system apart and putting just one short line direct into the handpump, drawing a bucket of water. Won't pull any of it through, it just sucks a little bit up, then when the handle pushes back, bubbles come up in the bucket. As I say, if I prime the pump with water first, it pulls it through

 

[Dads_Ale]

I checked today and more of a mystery. I tried putting water in Infront of the demand valve (so bypassing it) and the pump won't suck it through. It's almost like I have to feed water to the pump to generate enough of a vacuum to pull any liquid through the lines at the demand valve

@peebee No silicone hose in my setup, and I have the drain set up so it does empty the beer engine, there's definitely nothing left in it after I open the drain tap

Edit: just tried taking the whole system apart and putting just one short line direct into the handpump, drawing a bucket of water. Won't pull any of it through, it just sucks a little bit up, then when the handle pushes back, bubbles come up in the bucket. As I say, if I prime the pump with water first, it pulls it through

I was wondering how you have connected up the drain tap if you are able to drain out the cylinder?

 

[hoppy hannis]

g

 

[hoppy hannis]

I was wondering how you have connected up the drain tap if you are able to drain out the cylinder?

Not the best picture, but you can see the drain valve underneath. The demand valve is inside the keezer and the lines run through the collar. When I open that drain valve, all the beer comes out and there's definitely nothing left in the pump

 

[Dads_Ale]

Not the best picture, but you can see the drain valve underneath. The demand valve is inside the keezer and the lines run through the collar. When I open that drain valve, all the beer comes out and there's definitely nothing left in the pump

Can't quite see but is the drain coming off the beer in line? If it is I wouldn't expect it to empty the cylinder as there should be (if my memory serves me correctly from when I refurbished my Angram unit several years ago, although it looks like it was a different model) a non- return valve at the base of the cylinder to stop beer draining back into the cask. If your beer engine has one (or meant to have one) and its not working properly then this might explain the bubbles when you push the handle back up.

 

[hoppy hannis]

Can't quite see but is the drain coming off the beer in line? If it is I wouldn't expect it to empty the cylinder as there should be (if my memory serves me correctly from when I refurbished my Angram unit several years ago, although it looks like it was a different model) a non- return valve at the base of the cylinder to stop beer draining back into the cask. If your beer engine has one (or meant to have one) and its not working properly then this might explain the bubbles when you push the handle back up.

Yeah it is.It doesn't have a non return valve but I don't think it's meant to. That's why I have the demand valve inside the keezer as that's effectively my non return valve. I'm not 100% on the model as I got it second hand but I think it's an EWL Worthside and they don't have them. When I open that tap it definitely all drains out as you can hear the air being pushed out of the swan neck when it's empty and you pull the handle

 

[peebee]

Here's what @Dads_Ale was describing. It's a diagram sequence of a hand-pump's cylinder (same as an old fashioned hand pump for getting water out of wells:

The pump is usually left in position "D": Not one, but two non-return valves keeping the beer in the cylinder. Those valves do wear and can begin to fail. One indicator of a failed valve is beer or air will be sucked back up the spout (swan-neck).

There was someone a while ago describing a problematic pump that blew bubbles. Wonder if its relevant, wonder if it can be found ...

 

[hoppy hannis]

Here's what @Dads_Ale was describing. It's a diagram sequence of a hand-pump's cylinder (same as an old fashioned hand pump for getting water out of wells:

View attachment 60998

The pump is usually left in position "D": Not one, but two non-return valves keeping the beer in the cylinder. Those valves do wear and can begin to fail. One indicator of a failed valve is beer or air will be sucked back up the spout (swan-neck).

There was someone a while ago describing a problematic pump that blew bubbles. Wonder if its relevant, wonder if it can be found ...

Ok that makes sense, thank you! I've taken it apart to have a look at the mechanism, and there's a cooling jacket around the cylinder so I can't work out how to get it open to have a look at the piston and see if anything is broken. I wonder if I could put a non return valve on the barb hose fitting and if that would fix it...

 

[peebee]

Hmm ... can certainly so no harm trying. But the demand valve should be performing that function anyway. That lower valve probably does leak to allow the cylinder to empty when drain valve is opened ...

This is all speculation! Trying to distance fault-find is a bit tricky.

If the piston (upper) valve has also (partially?) failed it will not pump dry (i.e. pump air) so the demand valve stays shut as no negative pressure created to open it. That would explain why no beer can be drawn through initially. Once the cylinder is primed, the weight of liquid on the defective flapper valve will shut it properly and operating the pump increases pressure on the valve to keep it shut. So the pump pumps!

That fits! But you can't fix the piston flapper valve it seems? But if you had one of these demand valves (the RLBS ones I use):

RLBS Check Valve with Cleaning Lever

You can bypass the valve (switch to "Clean") and the light pressure (150mb) should push the beer past the demand valve into the cylinder and prime it (shift the demand valve to "Serve" before it starts emptying beer into the drip-tray!).

Hmm ... as I said, all speculation. And all from a very intelligent (err ... significantly brain damaged) individual. (That last declaration is a "you can follow my instructions but don't blame me if its wrong" ... okay?).


[EDIT: Thinking about it ... fixing a hand-pump like this makes it more suitable for home use! So no need to despair that your pump might be defective.]

 

[hoppy hannis]

Hmm ... can certainly so no harm trying. But the demand valve should be performing that function anyway. That lower valve probably does leak to allow the cylinder to empty when drain valve is opened ...

This is all speculation! Trying to distance fault-find is a bit tricky.

If the piston (upper) valve has also (partially?) failed it will not pump dry (i.e. pump air) so the demand valve stays shut as no negative pressure created to open it. That would explain why no beer can be drawn through initially. Once the cylinder is primed, the weight of liquid on the defective flapper valve will shut it properly and operating the pump increases pressure on the valve to keep it shut. So the pump pumps!

That fits! But you can't fix the piston flapper valve it seems? But if you had one of these demand valves (the RLBS ones I use):

RLBS Check Valve with Cleaning Lever

You can bypass the valve (switch to "Clean") and the light pressure (150mb) should push the beer past the demand valve into the cylinder and prime it (shift the demand valve to "Serve" before it starts emptying beer into the drip-tray!).

Hmm ... as I said, all speculation. And all from a very intelligent (err ... significantly brain damaged) individual. (That last declaration is a "you can follow my instructions but don't blame me if its wrong" ... okay?).


[EDIT: Thinking about it ... fixing a hand-pump like this makes it more suitable for home use! So no need to despair that your pump might be defective.]

My main issue is that I installed a drain tap in order to not have to clear the lines of old beer at the start of a new session, thus I waste less beer. At this point, I end up wasting just as much pulling through the water and beer mix until all the water is out