The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • Water Heater Anode Rod Replacement

    The Bradford White AeroTherm heat pump water heater that Came With The House™ has been running for three years. Based on previous experience with the same City of Poughkeepsie water, it was time for a look at the anode rod.

    Which, as always, required the Greatest Ratchet with a foot of extensions getting the 1-1/16 inch socket down to the rod:

    Water Heater Powered Anode - socket wrench
    Water Heater Powered Anode – socket wrench

    Remember to:

    • Turn off the water heater power
    • Shut off the inlet and outlet valves
    • Open the drain valve to relieve the tank pressure
    • Only then loosen the anode rod

    Seeing the first few inches justified extracting the rod:

    Water Heater Powered Anode - old rod top
    Water Heater Powered Anode – old rod top

    Due to low overhead clearance and inauspicious pipe locations, I had to hacksaw the bottom third off to extract the rod:

    Water Heater Powered Anode - old rod overview
    Water Heater Powered Anode – old rod overview

    Water Heater Powered Anode - old rod bottom
    Water Heater Powered Anode – old rod bottom

    With the rod out, draining a few gallons of water into a pan didn’t produce any notable gravel, so I didn’t do a complete flush. Much to my delight, the drain has a ball valve!

    Given that this is a fancy water heater and I no longer regard anode rod maintenance as a fun-filled activity, I installed a Corro-Protec powered anode rod for cathodic protection without all the crud:

    Water Heater Powered Anode - Corro-Protec parts
    Water Heater Powered Anode – Corro-Protec parts

    The wall wart proclaims 15 mA with a green LED indicating it’s hard at work:

    Water Heater Powered Anode - Corro-Protec wall wart
    Water Heater Powered Anode – Corro-Protec wall wart

    The data plate on the back reports 24VDC 15mA, but, being me, I poked at it with a handful of resistors:

    Corro-Protec power supply measurements
    Corro-Protec power supply measurements

    The electronics could be as simple as a 24 VDC wall wart feeding a 425 Ω series resistor and a transistor switch lighting the LED for currents a little over 6 mA.

    A quick ohmmeter check shows the powered rod electrode is open-circuit with respect to the tank, as it should be without much applied voltage. Applying +24 VDC from the wall wart drives 15 mA into the water: the rod is hard at work.

    I’ll take a look at it in a year or so just to see what’s going on in there …