My husband and I both now think this problem in shower is really a valve/cartridge problem... the plumber is not coming out until Monday -- the company said that they were not required to come out sooner because 1--the weather is still under 32 and apparently this plumbing co will not check frozen pipes when it is still freezing (unlike some others -- I know that is a jacked-up attitude) and 2-- we don't really HAVE an emergency since we have another shower to use and there is no evidence of secondary damage occurring-- frankly I think that is because we are using our home warrenty contract to cover this call and they know they can't jack up our rates -- We have no basement--house is in DFW TX area--homes here (unless they are built on sloping lot with serious elevation change)almost never have basements... We still have no prblem w/water flow in any bathroom except for this shower-- but we are letting it drip again tonight--and a sink faucet on an exterior wall...(just to humor me more than anything) Do either of you know if having a re-circulating HW system so that you get "instant" hot water when you turn on that tap makes a difference when you are trying to prevent freezing pipes-- I don't know how these plumbing lines are run for that system--and I have read there are couple of ways to design/install one...

Thanks! The problem leak is from the spout while the water is off, which we initially thought was valve-related, but doesn't seem to be now that the new valve is in and it hasn't stopped. It's a slow but steady drip. We do also have problems with a steady but small stream of water from the spout while the shower is running (and with a small stream of water from the shower while it's not supposed to be running) but those stop when the water is off, so I'm less concerned about them.

I had exactly your concern -- reaching in to turn on the water in our 3'x5' shower and getting my arm (or pajama sleeve) doused in cold water. We didn't have the problem with our old sliding shower doors, because the shower head end was accessible, but in our new frameless shower there will be a fixed glass panel on the left (the shower head is on the left hand side wall of the shower stall) and a glass door on the right. (We couldn't reverse the access, because there will now be a sink close to that left hand panel, leaving no room for a door.) We decided to move just the controls to the middle of the back wall of the shower, where it is much more reachable for someone standing outside the shower. We chose the simple Hansgrohe 04231 controller, so it should look fine by itself on the back wall.

I had another go at getting that chrome cover off. It was silicone'd in place :) Looks like my mixing valve is connected with PEX for the Hot, Cold and up to the shower head. The connection down to the tub spout is soldered copper. The other side of the wall is in a laundry room and the wall area is clear. I did find a video that showed the procedure for cutting the wall and replacing the mixing valve. I am not sure I want to tackle replacing the valve at this time. That's a good project for when I have a whole day available. I would have to borrow a PEX tool. I wonder if the threaded on connectors could be spun without cutting the PEX? Would that destroy the PEX seal? I have all the pipe soldering tools and copper pipe fittings. Here's a couple pics of the round brass valve/mixer and the valve itself. You can see the PEX connections left, right and up