it is a moen assembly sorry I don't know the actual valve models--no paperwork on that from the original owners and the plumber took the info I used to order the part--the part I ordered/replaced was 1423 Balancing spool Moentrol maybe something like this for the two-head control http://www.moen.com/products/T4111ORB ours is oil-rubbed bronze and it is installed with the lever at the top and the pull-out valve under it which looks the opposite of the Moen site photo the info on the Moen site says that it should turn from 'full cold to full hot' but there are stops the plumber came back out and said that when he put in the balancing spool he had opened the hot stop all the way and that if he closed the cool stop that it would not do any good because the balancing spool would basically just reduce the flow of water to make sure the balance of hot/cold stayed the same... he said that there is movement underway to basically take the choice out of amount of hot water coming through faucets and showers--that safety of not burning/scalding people is overriding someone's desire to have a 'HOT' shower... when I asked about replacing the valve/lever with one that would swing right/left to allow me to regulate the balance of hot/cold... he said it would be too expensive to actually change the control to that type of fixture because we would have to open up the shower wall--take out tile--replace it... so we are basically stuck with either setting the water heater to higher temp because that will bring hotter water to the mix and will be expensive choice or just learning to live with it like it is I plan to take a shower in the two upstairs showers and see if their water is hotter than the one downstairs--- he said that the master shower is probably farther from the water heaters--and it might be farther than the other downstairs shower by just a little...which would influence the water temp at the head... both water heaters are upstairs and closer to those showers... it is just very frustrating to find out that something we really did not consider all that much would become so frustrating... I don't take long showers--and I don't use the big tub at all--don't consider that I waste water compared to larger families or people who take a 15 min shower...so this irks me to no end-- our old house with its old shower had wonderful hot water and I am really going to miss it... Here is a link that might be useful: shower valve

Probably non-metallic piping which has been firmly clamped against a wooden framing member (big mistake). The piping changes dimensions with changes in temperature--expanding when heated -- no power on Earth can prevent it from doing so. It slips in the clamp and each such movement produces the chatter that you hear. It may gradually lessen over time with wear on the pipe and clamp. Or open the wall now and correct the problem. Classroom study of chemistry and physics is helpful in understanding materials and accommodating to the characteristics of those materials.

I doubt very seriously if the failure of the humidifier supply tube is a result of heat. First of all, let us consider the temperature of your incoming cold water supply. The mean average of the earths crust is 55degF (geothermal temperature of the crust). Soil is a rather poor insulator so the surface soil then cools proportional to the ambient air temperature. While the crust is 55degF the actual surface of the soil will freeze for a short depth which we define as the "frost depth". While the frost depth is the deepest point at which freezing commonly occurs it must be understood that from that depth the temperatures increase gradually from freezing temp(32degF) to the natural geothermal temp(55degF). Typically geothermal temp occurs at approximately twice the frost depth. In order to protect our water lines from freezing the codes require that we bury the line 6" below the frost line thus when the dirt is frozen to the frost depth the average temperate at the water line may be only slightly above freezing (34degF+). Fresh water reaches a maximum density of 231cu.in per gallon at 39degF. There is a very coplex formula to determine the rate of linear expansion but for the sake of illustration let us use the maximum here. When water is expanded from its maximum density of 39degF to the boiling point it expands by approximately 40:1 thus we could say the physical volume of a 40gal. water heater expands by one gallon. To put this in perspective consider that a 1/2" pipe has a volume of one gallon for each 98 linear feet. We must now keep in mind that water is not compressible therefore as the volume expands it must go somewhere. Normally the increase in volume is compensated by physically pushing some of the water back to the municipal main or to your well pump pressure tank however if we install a check valve in the line there is no place for the additional volume to go. In this case the excess volume would by necessity be relieved by discharging through the water heater Temperature & Pressure Relief Valve (T&P valve) BUT let us consider another potential problem here. Imagine for the moment that your T&P discharge line discharges out through the wall of your house. The discharge end of the line is then exposed to atmospheric temperature and in a worst case scenario the outside end of that line could freeze shut. At this point there would be no place for the additional volume to be released and it could result in blowing out fittings or valves or rupturing a pipe or the water heater vessel. Now keep in mind that the T&P valve is a spring loaded valve that is set to release when the pressure reaches 150psi and most likely the plastic line to your humidifier is failing slightly before the internal pressure is sufficient to release the T&P valve. On the other hand, if you did not have that plastic line there is a very strong likelyhood that the increased volume could be relieved by blowing out a compression fitting at a fixture angle stop, a pipe joint might fail or premature failure of Bibb Washers in your faucetts. The proper solution is to install an expansion tank on the water heater side of the check valve to absorb the increased volume. Installing an expansion tank is quite simple. You simply install a Tee on the cold water line with a male thread adapter on the Tee stub out, then screw the expansion tank onto the thread adapter.

Maybe there could be debris, and I could have the plumber come back next week if the pressure won’t go back up. However, I’d stil like to know if there is any method to vary the pressure on the hot water side so it isn’t just full pressure or nothing. I’d like to be able to adjust the water volume on the fly and maybe use more pressure when I turn on the hand held attachment to wash out the shower and spray away Bon Ami residue from the tile than I would use for actually showering. I neither want to shower under a power washer nor have such low water pressure that it can barely rinse the soap off.