I have a customer who was purchasing a home and the previous owners removed the valve retaining ring and shower valve. The temperature balancing cartridge was left in place and now I am looking for a replacement. I first thought it was Delta because of the spring and rubber seat. but the valve retaining ring is smaller than a DELTA, one piece cartridge. I spoke to another plumber and he thought American Standard, but the replacement balancing cartridges I could find have a different inlet configuration (red seal).
Any thoughts would be greatly appreciated