Just finished building my somewhat modest master bath addtion (I did all the plumbing myself). My experience deals with a stand up shower in this particular instance. After some resarch, I decided that I did not need to spend north of $2k on Kohler thermo valve, and I did not need 15+ GPM with 3/4" inlets. By the time I added the body sprays and a couple of shower heads i was in for over $3k which was way over budget. I ended up doing a Moen Vertical Spa. IIRC, I think it was about $1,300 with two shower heads, 4 body sprays, a handheld shower, 5 position diverter valve, and the thermo mixing valve. I just fired it up last week and am very happy with the whole set up. Moen does a nice job, they have some great info on their vertical spa and thermo valves on the moen.com website. It took me a full day to pipe, but I used long radius elbows and took my time to ensure good flow. Having both the pressure balanced and a thermo valve, I prefer the thermo valve and being able to adjust the flow volume. Plus I think it looks better. I ordered it online from faucet.com, no tax + free shipping....plus they price match. If you google the part number and you find a lower price and email it to the price match department and they re-quote the product. Customer service was superb and ended up ordering my sinks, faucets, med. cabinets, and towel/TP holders from them. Again, with no tax and free shipping the net result (to me) was a great deal. I go out of my way to keep from purchasing at the big box - but that might be my personal grudge, but they dont have anything "good" in shower valves in stock any ways, so why bother ordering it from them? Hope that helps.

I feel your frustration. Thomas Hardy said "try to learn something about everything and everything about something" but it's awful hard to do. I find it difficult to believe that a licensed landscaper would design and install an irrigation system without considering the service flow rate of the plumbing. In reality they are adding X many faucets around the lawn and that will have a profound effect on the appliances and fixtures in the home when they are on. Do we add 5 drip stations, 10, 100? How many will the plumbing system and flow rate support? You might call the landscaper and tell them you're having a problem. See what they say although after two years they may not care, but maybe they would and could offer their experience and advice. Perhaps the simple solution is to divide the irrigation system into smaller zones and decrease the demand into smaller demands over a lengthier time period. The resolution to your problem may be as simple as cleaning the screen in the PRV or more complicated. I don't think your plumber is trying to rip you off I believe he is operating at the level of his skill and knowledge. Your problem requires more than a faucet replacer. If I were in your situation, as frustrating as it will be, I'd search till I found a plumber who made you feel secure in his/her knowledge. A plumber who did pull out a gauge and check the pressure. He or she may be hard to find but the search will be worth the trouble. Perhaps call your local plumber's union and ask for a list of master plumbers. Don't forget to ask about a thermal expansion tank.

You won't be able to find parts for it because that is a safety device and the ASTM standards state that anyone who builds or rebuilds one of those valves must have the means to test and certify it before it can be put back into use. The tag that your dealer asked to see was the original test certification tag.

The ones with one knob, you are really adjusting for temperature only. The only way to get less water is to go cold. I have had a Delta Pressure-balance system with one knob for years. No volume control, really, unless you don't care about the temperature. The only other way to control the volume is to get a shower supply pipe with a T coming off of it for a handheld. I have a valve up there where I can choose the shower head or the handheld shower. If I choose the handheld, I have another valve on that head that allows me to turn the volume to whatever I want. None of that has anything to do with the Pressure-balance system, though. That is still set at the same setting through all of this. My new system will be a Temperature balance system with three volume controls. I will be able to turn the shower head on full, off or anything in between, ditto for the handheld, and ditto for the rain head. The water heater will not support all three at the same time, but we are a house of grown ups and if we try that kind of shenanigans, we will suffer the consequences of finishing with a cold shower! I usually turn it all off to soap up now. I imagine I still will do that, and the rinse will be faster with the rain head. I am hoping to use less water with the new system, with less time fussing with valves.