March pump cavitation issue when boiling

[MikeMMM]

I’ve used my March pump for probably 80 batches now. Circulate the last 15 minutes of boil then go to chill while continuing the circulation. Never a problem. Then maybe 10 batches ago I’d get cavitation from the boil maybe once During the 15 minute boil, bleed and Then all good. But over time it has gotten worse and now I can’t use the pump at all during the boil. Works fine at just under boil but as soon as there’s any simmer/boil it cavitates and I need to kill it. Nothing has changed in my brew setup. I’ve changed my QDs just in case, taken the head apart but it’s clean. Motor runs fine, quiet. Just the loud noise it makes at cavitation then I quickly shut it down. Any ideas?

 

[day_trippr]

I'm surprised your Chugger didn't always complain loudly running it wide open during a full boil.
How long of a hose do you have between your kettle and the pump input?

Anyway, when you opened the pump head did you notice if the Teflon thrust washer was still there and in reasonable thickness?

Cheers!

 

[MikeMMM]

I'm surprised your Chugger didn't always complain loudly running it wide open during a full boil.
How long of a hose do you have between your kettle and the pump input?

Anyway, when you opened the pump head did you notice if the Teflon thrust washer was still there and in reasonable thickness?

Cheers!

Updated the post. It’s a March pump. But anyway the thrush washer is paper thin. I’m not sure if it comes that way or if it wore down. I was just thinking of getting a new one. I’m giessing it has to be something like that. I have two different hoses I use for the inlet side. One is maybe 3 ft the other is 5.

 

[brewkinger]

But anyway the thrush washer is paper thin. I’m not sure if it comes that way or if it wore down. I was just thinking of getting a new one. I’m giessing it has to be something like that..

That would be exactly where I would start as well after cleaning the pump. Pick up a couple of spares while you are at it.

 

[day_trippr]

Yeah, I run a pair of venerable 815pl pumps and you need something more than "I can see through it!" thickness on the thrust washer
Otherwise eventually the impeller will rattle and screech your brains into mush (bt/dt, bought two dozen washers).

Still, I do not try to recirculate flat out during a full boil because there's not much point to it - the wort is moving about nicely all on its own - and my pumps don't like it. Once the post-boil wort temperature has dropped a mere 2-3 degrees I can run the pump for post-boil hop whirlpooling without it bitching at me

Cheers!

 

[MikeMMM]

Yeah, I run a pair of venerable 815pl pumps and you need something more than "I can see through it!" thickness on the thrust washer
Otherwise eventually the impeller will rattle and screech your brains into mush (bt/dt, bought two dozen washers).

Still, I do not try to recirculate flat out during a full boil because there's not much point to it - the wort is moving about nicely all on its own - and my pumps don't like it. Once the post-boil wort temperature has dropped a mere 2-3 degrees I can run the pump for post-boil hop whirlpooling without it bitching at me

Cheers!

Thx for the replies. I’m running it last 15 min of boil to sterilize it for the whirlpool/chill. If I had this problem all along I would say it’s just the limitation of the pump. But the fact that I’ve done maybe 70-80 brews with it running it the same way with no issues makes me believe it’s that thrush washer. You guys know where I can get those? Not finding them anywhere online.

 

[RPh_Guy]

You can cut that time down to 2 minutes or less, and you don't need to run it at full speed.

Boiling hot wort will sanitize it pretty much instantly. (And mash temp already sanitized it, by the way, if you recirculate the mash).. And whirlpooling isn't really helping you at that point in the process.

Food for thought (after you replace the gasket).

 

[day_trippr]

I'm pretty sure I got my thrust washers from AIH.
https://www.homebrewing.org/Thrust-Washer-Front-teflon-March-Pump-_p_2498.html

Cheers!