Weird problem with shower

[Rich Hardenstein]

I have an unknown manufacturer "single control" shower. When the handle is at 6 o'clock, it is off. Between 6 and 3, turning CCW, the flow of the cold water increases to a maximum flow at 3 o'clock. Between 3 and 12, again CCW, hot water starts getting blended in but around 2 o'clock the flow abruptly decreases to about 10-20% of the flow volume at 3 o'clock. Between 2 and 12, the flow decreases even more, so at 12 o'clock, the flow is barely on, maybe 10% of the maximum flow volume.

Primarily I need to know how to disassemble the unit and fix the flow issue. I'm hoping just replacing the 'stem' will fix my problem. I'd kinda like to know who made the unit. It was probably installed between 1997 and 2009.

There are no markings on the unit that I can see and I've looked closely.

Here are three photos I took to help identify it...







Thanks in advance!

 

[JohnfrWhipple]

Looks like your hot water shutoff is in the off position...

You could have more little gear clogs showing behind the handle as well.

Best to wait for Jim - he will goggle something for you.....