Moen TS3411BN ExactTemp Single Handle Thermostatic Valve Trim in Brushed Nickel

Remodeled the shower using the Moen Spa (TS270) system in 2012. The thermostatic temperature control is problematic. I've replaced the most of the parts and it no longer works as it did when first installed. Temperature over-ride limiter does not reset or operate as advertised.

The product numbers are TS3411BN & TS3600BN. We built a new home and chose this product because of good experience with past Moen products. The red button on the ExactTemp valve was not popping out with any consistency. The original installer left NO instructions on how the valve should work, so I contacted Moen Customer service who promptly sent me instructions. At least we knew HOW it should work.. The 1st repair plumber told us the temp valve was installed backwards, so he "fixed it". After he left we could only get warm water, no matter if the red button was in or out. The 2nd plumber came out and said the 1st repair plumber installed the valve backwards. So, he messed around with it and now the handle turns hard and the red button is not popping out at all. We at least get warmer water now but for the extra $$ we paid for this shower valve, it is not worth it.. How can installation be so complicated? I went on the Moen website and printed the installation instructions. I am now going to call the repair place for the 3rd time and find out if anyone in the shop knows how to install the ExactTemp valve. I am no plumber, but it looks like the valve has to be turned to various clock positions based on the temperature setting of my water heater! I am tempted to do it myself but I don't want to have a flood in our house. Does Moen ever send or check whether plumbers know how to install these temp valves??