Whirlpool during boil is a struggle...

[Hwk-I-St8]

I'm relatively new to the whole pump/whirlpool scene (two batches that way now), but I've seen the same thing both times. A friend said I should run the pump for about 10-15 minutes at the end of the boil to sanitize the pump.

No big thing, right? Well, what I'm seeing is that I have hard time keeping the pump from running dry. I prime, intake hose is full and even through the pump and half of the outflow hose is full.

When I run the pump, I can see the wort level in the intake hose dropping closer and closer to the pump until it finally cavitates and I have to turn the pump off. If I throttle the outflow, I can keep from having to turn the pump off, but even at pretty low flow levels, I struggle to keep the intake side full of wort.

Then, after I turn off the burner and the boil subsides, I can pump with the outflow valve wide open and it works great.

I'm guessing this is an issue with the boil interfering with wort getting into the intake port, but I'm curious if others see this and if there's a way to resolve it.

For reference I'm using:

BrewBuilt 10 gal kettle with a Spikes 5/8" ID dip tube that draws from the bottom at the edge. I'm using a center inlet chugger pump. I pump to a 1/2" diameter whirlpool arm from stainless brewing (they call it a whirlpool racking cane and it goes over the top of the kettle, not through the side).
I have a ball valve on the pump outlet side. I'm using 1/2" silicone tubing and 1/2" ball lock quick connectors.

Thoughts?

 

[Ozarks Mountain Brewery]

cut the ball valve down to half, the boiling water creates bubbles inside the pump and its not a constant liquid flow, restricting the flow helps that, you can back it off then play with it to get the best results

 

[Hwk-I-St8]

cut the ball valve down to half, the boiling water creates bubbles inside the pump and its not a constant liquid flow, restricting the flow helps that, you can back it off then play with it to get the best results

That's what I've been doing. I was wondering if this is typical and/or if there are other solutions.

 

[Ozarks Mountain Brewery]

if you start the whirlpool before the boil or after but still above 200f it works just fine, its just the boiling action that throws the magnetic pump off

 

[BrewKaiser]

How is your pump head oriented: Horizontal or vertical?

You may get some benefit from having the inlet pointing down and outlet pointing straight up.

You may also want to install a bleeder valve on the output side to bleed the air.

As other's have said, some fiddling around with flows and orientation will result in you finding the right balance.

 

[Hwk-I-St8]

How is your pump head oriented: Horizontal or vertical?

You may get some benefit from having the inlet pointing down and outlet pointing straight up.

You may also want to install a bleeder valve on the output side to bleed the air.

As other's have said, some fiddling around with flows and orientation will result in you finding the right balance.

I had the outlet oriented up the first time I brewed, to the side this time. Because of the weight of the quick connect fitting and a 3/4" to 1/2" adapter, it wants to lean with the input down a bit. I tried it that way and tried propping it up a bit. Nothing worked well while it was boiling.

 

[woo_pig]

I pump the whole time. Its alot easier to work on 154 than 200

 

[beermanpete]

I have the same problem but during knock out. The heat seems to cause gas bubbles to form in the line feeding the pump causing cavitation in the pump. You might try placing the pump lower in relationship to the kettle. This will create a larger head pressure and reduce the tendency for cavitation.

 

[eric19312]

I have same issue. Frustrating at first but you will learn how to deal with it. You need to throttle the pump on the outlet not the inlet side. At a boil you will only be able to run at maybe 25% open. That's fine to sanitize the pump and recirc lines. Once you start chilling you will be able to increase flow.

 

[day_trippr]

That's what I've been doing. I was wondering if this is typical and/or if there are other solutions.

It's mostly physics in action. Your kettle is filled with boiling wort, and the harder the pump draws the lower it's trying to drop the pressure in the plumbing - which lowers the effective boiling point of the wort, which results in bubbles in the line that collect at the high point and work towards the pump.

At full boil I have my pump throttled way down - like 1/4 of the max flow.
As soon I start cooling to whirlpool temps within a few degrees drop from boiling the whole problem disappears like magic...

Cheers!

 

[Bobby_M]

It doesn't take 15 minutes to sanitize at boiling temps. Just run it for 2 minutes at flameout.