Thumper going empty

[Country boy]

I got a 15gal keg and use a 7.5 gal keg thumper. My question is when I make a run my thumper ends up empty. I’m I just not putting enough water in it? If so how much should I be putting in it? I was putting about a 1/4 of water in it. Or do I have something else going on I need to fix with the setup?

[jon1163]

What's in your Thumper and what are you putting in your boiler? How far are you running down your run in terms of ABV?

[fizzix]

You're probably getting suck back on cool down. Break a fitting loose when the run's finished to relieve the vacuum.

[jon1163]

You're probably getting suck back on cool down. Break a fitting loose when the run's finished to relieve the vacuum.

there's that too

[Wild Bill]

Almost no way possible for thumper to go dry during a run, in fact they will usually gain volume. I would say Fizzix nailed it with suck back after flame out/power down. Break a union loose or a triclamp at end of run to prevent. I have a little 5 psi relief valve threaded into a 2” tri clamp endcap on top of boiler tee that I pull open at end of run.

[Kareltje]

+ 1 on fizzix, jon1163 and Wild Bill.
Even if you start with an empty thumper, you can not end with an empty thumper. Due to losses the condensing vapour from the boiler will lose more heat (and thus volume) than it will cause renewed vaporization.
(Unless you have a fire under the thumper, of course!)

You should disconnect the tube from boiler to thumper right after finishing the run.

[Country boy]

What's in your Thumper and what are you putting in your boiler? How far are you running down your run in terms of ABV?

I was just putting water in it. I was running a corn and caramel malt mash in the big keg. When I used the thumper it goes for 130-140 proof till the thumper runs of of water some how it drops fast to 90 and keeps dropping

[Country boy]

Almost no way possible for thumper to go dry during a run, in fact they will usually gain volume. I would say Fizzix nailed it with suck back after flame out/power down. Break a union loose or a triclamp at end of run to prevent. I have a little 5 psi relief valve threaded into a 2” tri clamp endcap on top of boiler tee that I pull open at end of run.

I don’t know I thought the same thing but it’s happened on two different runs. So I’m going to try just breaking a union loose the next time I run

[goose eye]

Don't like it dropin like that then shoot it

So I'm tole

[hellbilly007]

Is there a chance your thump is plumbed backwards?

[bilgriss]

Outbound plumbing has to be above liquid level.
You can put a ball valve in-line to open when you cut heat, to prevent suck-back.
You aren't applying any heat to the thumper while it's running, are you?

[MoonBreath]

Inlet 1-2" off bottom, knotched or drilled.
Outlet 1" below Top of thumper.
1/2 full for starts..Add cork to 'shoot' and keep to a workable level per goose's advice.

[Country boy]

Inlet 1-2" off bottom, knotched or drilled.
Outlet 1" below Top of thumper.
1/2 full for starts..Add cork to 'shoot' and keep to a workable level per goose's advice.

Yeah that’s how I got it set-up I’ll try filling it up half way. I probably was not putting enough water in the thumper. Thanks for the advice guys.

[Country boy]

Outbound plumbing has to be above liquid level.
You can put a ball valve in-line to open when you cut heat, to prevent suck-back.
You aren't applying any heat to the thumper while it's running, are you?

No no heat being added to the thumper.

[Antler24]

Next time you run break the union when you finish. My bet that's where it's going. I did the same thing after my first run with the thumper. I run the same setup as you, and love it.

[Walshie]

Newbie here; When I gave my 8 gall distiller its first run on old cherry wine, I used the wine in the one gallon thumper as well and mine ran dry. I assumed it just evaporated in the heat of the moment as I'm sure I released the thumper before the keg. So if read correctly you can't get the temperature high enough to evap it?

[Yummyrum]

Always be careful breaking open a union after killing the fire. There’s a lot of painful steam comes out that joint for several minates .... I know

[Kareltje]

One can run the boiler dry or overflow the thumper. But running the thumper dry? That is not possible.
Sucking it dry can be done within a few minutes, if and when the inlet tube is open.

The thumper is heated by the condensation of the vapour coming from the boiler. When the boiler is dry, there is no condensation, but then the thumper is not heated anymore and stops distilling. The fluid in the thumper then stops boiling and remains there.