I'm not happy at how intollerant they are to any amount of air. I teed my sight glass off the output of my BK and it allowed it to suck air in for a very brief amount of time, less than 5 seconds. These things howl the second any air gets in them.
The chugger does seem more persnickety than the March when it comes to grabbing air. And it does make the dying cat noise when doing so, unlike the March. My March is a plastic head and the Chugger is stainless--I wonder if the head material has something to do with the noise?
I run the pump with the outlet facing straight up--which I think makes the most sense for removing air as quickly as possible (air travels up). If not running that way--maybe try that.
The Chugger also has more suction than than the March--cover your finger on the inlet and you can feel the difference-- so maybe that has something to do with it too. The inlet on the head of the Chugger is larger for sure than the March.
All and all--I have to try to make the Chugger fail--in order to get it to fail. (Fail--> just means loud noise causing me to turn the pump off and than having to turn back on to restart. )
When brewing the way I normally do--> I have zero problems--> i.e. moving sparge water (160-190F typically--I don't get too exacting on sparge temperature), moving wort from mash to kettle (160-170F), and whirlpooling immediately after flameout (212/211F all the way down to ferment temp).
I have to run the Chugger at a rolling boil of wort, or introducing air to the inlet (yes even briefly = failure) to get failure.
Also, the Chugger seems to like more viscous fluid (i.e. wort). With the tests I ran, (15 gallons of) water causes failure at a lower temperature. I got partial failure at (brief noise that stopped on it own quickly) 202F with water. However, with wort--> I can run the pump up until rolling boil with no problems.
Changing the inlet from my double elbow (more restricted flow) to a (much less restricted flow) straight inlet--> made no difference in the tests I ran.
I'll be interested in seeing the issues resolved because I think people with plate chillers and the like, as stated by others, have a need for pump to move water at at or near boiling temperature.
That said, again, for me, the present issues are kind of a moot point because the pump does not fail at all when I brew the way I normally (and always have) brewed.