Furnace Zone Shutoff Valve

The upstairs baseboard heating loop collected enough air to frustrate the circulator pump, so I had to close the zone shutoff valve and open the drain valve to flush enough water through the plumbing to get the bubbles out:

Except: turning that little slotted stem required more torque than I was willing to apply. It may have last been turned a decade ago, during the final furnace servicing on record, but we’ll never know its story.

Three days of dripping Kroil penetrating oil onto the shutoff valve stems and, just in case, their pipe threads, along with applying the maximum torque I was willing to apply, did the trick, albeit with a distressing amount of squeaking.

A hose from the drain valve to the sump pump pit took care of the outgoing water, flushing proceeded uneventfully, a test firing put hot water into the baseboard, and I could declare victory for the oncoming heating season.

For the record, this was an occasion justifying use of a slotted bit from my Brownell’s Magna-Tip Super Set:

It’s not a perfect fit, but much less sloppy than any other screwdriver in the shop: this is one valve I do not want to abuse.