Here are images of our weird installation. This is in the maximum "hot" position (as far as the lever will go). And this is an image with the handle in the maximum "cold" position. Here is a picture of the two white rings ... we think the narrower one is supposed to be installed in the wall, on the other side of the trim plate. Is this correct? As it is now, we can get very hot or warm water, no cold. The lever can be moved about a quarter way around altogether (the first two images illustrate the maximum movement of the lever). He measured the water temperature when he "fixed" the stainless sleeve (the notch was originally on the bottom instead of the top and we KNEW that was wrong); he adjusted the green nut so the water was 100 degrees when the ring was on the numbers "100" ... but I assume the position of the lever itself matters as well (and must have to be adjusted relative to the numbers on the white band since why else are they there?), since as it is, you can't even MOVE the lever to the lower numbers. HELP!!!! Am I not understanding something here? I have to be able to explain in REALLY simple words to this guy what this should look like and how it should function. He thinks it's just fine and clearly didn't really understand why the notch (by which you determine where you align the temperature number) had to be on top -- where it could be seen. I had the sense he felt he was humoring me by moving it :)

This has discussion has a lot of great information. I'm not sure if everyone's questions have been answered but we have a very in depth article on our site regarding the difference between the Delta 17 and 17T series trim kits. It gets pretty heavy into the details. Others above have given a pretty good explanations in this discussion but I think some aspects may still be a little unclear. Here's a summary of the differences detailed in our article. 1) Water pressure: 17 Series cartridges operate using pressure balancing techniques as opposed to actually sensing temperature. This means that water pressure from a 17 Series trim will be less than a 17T Series. 2) Temperature limit stop: If you live in an area where seasonal temperature differences are greater, you may have to adjust the temperature limit stop in your 17 series shower periodically. You will never need to do this with a 17T series. 3) Accuracy: 17T keeps the temperature in a tighter range. If you adjust the temperature handle more often the 17T will give you more predictable results with less fiddling around required to get exactly the temperature you want. 4) Shower systems with multiple spray outlets: In the case of a shower system you will require more water pressure and a 17T will be better. You will also get better pressure from a standard showerhead with a 17T. These are some of the reasons the price is higher. For more info check out our article: https://faucetlist.com/blogs/buying-guides/delta-thermostatic-shower-faucet-trim-kit-cartridges-monitor-17-series-vs-17t-series-tempassure read the guide

Am I missing something? I just read/skimmed through the instruction booklet linked above (pressure balanced valve, not thermostatic) and I couldn't find anything about connecting the valve to the framing other than "step 1 - connect valve to framing". My valves don't have any holes where I can put a screw through or anything like that. I'm confused..... Here is a link that might be useful: Kohler thermostatic valve instruction book

Thermostatic is the way to go. The pressure drop on a tankless system, which is caused by both the added restriction of the heat exchanger(s) besides the throttling of the water at the outlet control valve, cause the havoc with pressure balanced valves. Pressure balanced valves were initially designed for flushing toilets as one need to help eliminate scalding when the cold pressure drops. Well with a tankless it is just the opposite, and the valve restricts the cold, compensating for the hot, always searching for the best position and restricting flow some or all at times in the shower.