So, it figures, after the Noreaster and our power finally came back on there was some dirt in the water lines (somebody emptied the toilets so the pressure went away…) and it went straight for the pressure-balancing control on the shower where the kids needed a bath. All hot water (from a ‘Moentrol’ unit).

I disassembled the trim and handle, checked the spindle (fine), checked the shutoffs (water there!) and then took out the balancing spool (this requires the biggest screwdriver you can get from Sears, leaning on the screwdriver, and a good grunt and twist – what a bad design) which was absolutely seized up, blocking the cold water input.

Being after the stores had closed and not being in the mood to spend $70 on a new one, I figured I’d try everything, and worst case, I could buy a new one the next day after a long drive to a Moen parts dealer (our local one doesn’t stock Moen). So I tried tapping it, soaking it in vinegar, no dice. Next I tried blasting it out with as much water pressure as I had, then with 90PSI from the air compressor – again, no dice. Then I tried boiling the vinegar, which actually got it pretty shiny and would allow the stop to move if I smacked it real hard with the handle of the aforementioned gigantic screwdriver), but really hard and not reliably. So, then I thought that being metal-in-metal, perhaps some expansion would work, so I put it on the gas range on high for 10 minutes (turning once during cooking), and, sure enough, there were a couple of pops and snaps while it cooked. Note: remove the O-rings first. Once it cooled down for 20 minutes I could get the stop to move pretty well with a good rap from the screwdriver handle, so I brushed some silicone grease inside and outside the unit, re-installed the spool, tried it, remembered to turn the water back on, tried it again, and voila, clean kids.

So, I’m not actually sure if the heat caused it to expand and contract, re-seating something, or if those snaps, crackles, and pops were the sound of some big, stuck dirt particles exploding, but either way, I didn’t have to buy a new one and it got the kids to bed clean.

I’m writing this for the archives – hopefully it will save somebody some time and $70 in the future. And next time I’ll empty the lines in the basement utility sink which has no sensitive components of any sort in it.