So I finally noticed that the water wasn’t nearly as soft as it used to be, which usually means I forgot to dump a bag of salt in the tank. This time, the water was halfway up the tank, which usually means something’s broken.
The usual cause: crud clogging the filter screen upstream of the venturi that sucks brine out of the tank. The usual fix: rinse the screen.
This time, however, the screen was clean. Pulling the gasket off the nozzle assembly revealed a collection of particles and chunks inside the fluidic channels; this is what the gasket looked like after I sorted everything out.
The gasket has at least three layers: a stiff red backing, a compliant green middle layer, and a white surface layer with molded channels matching the red nozzle. The two black cylinders are metering plugs with precisely shaped orifices that control the 0.1 and 0.3 gallon/minute brine and rinse flows.
The green and white layers evidently disintegrated into chunks that blocked the nozzle. With no flow through the venturi, the tank could fill until the float valve limited the flow, but the brining step had a very, very low flow and the resin bed eventually ran out of capacity.
I ordered a replacement nozzle and gasket assembly, figuring that Sears (actually, its OEM supplier) might have changed things in a non-compatible way. The old part numbers, which will get you the new equivalents:
- Gasket: 7163663
- Nozzle + gasket: 7187772
The new parts looked like this:
Surprise! The fancy molded gasket is no more; the replacement is a flat rubber sheet with the appropriate alignment notches and holes. The nozzle assembly might have come out of the same molding machine on the same shift.
I reassembled all the fiddly parts, manually set the softener to its Brine stage, let it suck a few inches of salt water out of the tank, and then returned it to automatic operation. At this point, the water heater is full of hard water and it’ll take a few repetitions of that cycle to get back to normal.
Given the limits of the gasket’s resolution, I’m sure the Batman icon is completely coincidental and sincerely regretted…