delta single handle shower control

I had to repair a delta single handle shower control that was leaking. I replaced the o rings and the washers and springs and found that it did not stop the leaking, which was a steady trickle. When I checked the delta web site they listed the above as step one and if the leak continues then step two is to replace the whole unit. When I went to the plumbing shop to get the whole unit I found it was $70, the new unit worked fine. The guy at the plumbing shop said that on the delta one handles springs and washers rarely stop the leaking. Can anyone tell me why and what is the function of the twist apart piece that makes up this unit. Big difference in costs from new springs and washers to a whole unit. Comments appreciated. -Don

delta

You must have a Monitor series valve. You could have called Delta and they would have sent you a new control component, although sometimes they just send the "O" rings and washers, depending on which person you talk to. Replacing the entire unit on those valves is the best way to repair them. The older valves were repaired by replacing the springs, seats, and ball.

On the cartridge you have, the seats and springs perform the on/off function. The lower portion of the cartridge is the pressure balance spool, which performs the anti-scald function.

Thanks for the info. I am not sure I understand the funtion of the back part of the unit that twists into place. It seems the anti scald is simply an adjustable stop on the front behind the handle that limits the travel of the handle. The back part of the unit twist off and has the hot/cold inlets with orings and the out lets with the springs and washers. There is something inside the back part that rattle when I shake it. ??? Really didn't have the option to deal with Delta as the family I was working for needed the shower. This is a great site, lots of good info. Found it by a reference on the John Bridge forums, also a great site for tile and related work. - Don

A high temp limit adjustment and a pressure balance system are not the same thing at all. The first just limits how much hot water you can normally turn on. The second prevents it feeling much hotter if the cold water supply suddently looses pressue, like when someone flushes a toilet. If the cold water is restricted, it causes it to also restrict the hot water in the valve, thus trying to preserve the overall mix and the temperature; preventing you from being scalded by the loss of the cold water pressure. You'd notice a momentary pressure reduction in the shower, but not a spike in temperature.

Thanks, I understand now. I will probably take this old unit just to see for curiosity's sake. - Don