Running little brown pump dry

[squirt in the turns]

Does it hurt them? I don't make a habit of doing this, but when it has happened, the LBP hasn't screeched like a dry March pump.

I want to install float switches in my MT and kettle so that I can fly sparge without having to watch the rig constantly. The switch in the MT will turn on an LBP to move water from the HLT to the MT as required to keep the liquid level just above the grain. The one in the kettle simply turns off the March pump (which moves wort from the MT to the kettle) when pre-boil volume is reached, which stops the match pump running dry (if my volume calculations are correct this coincides with the MT just about being fully drained).

The situation this leads to is that after the HLT empties and the liquid level in the MT drops, the LBP will run dry until I come along and turn it off. I realise that I could just wire the MT switch in series with one in the HLT, BUT THERE ARE TOO MANY WIRES ALREADY! :blink:

 

[Yob]

Does it hurt them?

Yes.. not a great thing for them

 

[squirt in the turns]

Thanks Yob, I guess I'll have to include a switch to shut off the LBP when the HLT is nearly empty.

 

[TheWiggman]

These LBPs have a small black seal in them which rubs on the drive shaft. With no liquid it's not cooled, and will likely melt if run dry for a little while. Short (<2 secs) bursts are fine.
They're also only a 12V item and don't draw much power. I intend one day to put one on my HLT and bought a stainless float switch off eBay. Run the float switch in series with your power source and straight away you've got simple run dry protection with essentially no extra wires.
Float cost me $16 by memory.