thanks much for this information. yes, we do need to get a bigger tank for the well.... however, this problem has been solved with a pressure valve near the tank. wish i could tell you more specifics...but i can tell you that the installer tried putting in a valve (he heard that this would cure the problem) and it didn't help at all. when he returned after a few weeks, he decided to call rinnai again, and he talked to the right person. he needed a bigger valve of some sort.... installed it... and it fixed the problem! i'm so happy about this.... and we will work on getting the well in check as soon as po$$ible!

You now have two new thermostats and two new heating elements in a pressure vessel that does not leak. In essence you already have a new water heater. What you do not have is a plumber that understands electricity. What you now have is one of three problems: 1. The Thermostats are held in place by spring clamps. Sometimes while removing the old thermostat the springs are stretched too far forward and once the new thermostat is installed it is not held tight enough against the tank wall. That will result in a slight air gap between the sensing element on the T/stat and the tank wall which causes the t/stat to get a false reading. The t/stat is not triggering correctly and the lower heating element is not being turned on. Generally when that occurs the water heater will produce super hot water that will run out almost immediately when the hot water is turned on or the reset button will pop out frequently. The solution is to turn the power off, remove the upper t/stat and slightly bend the springs so they will give more force in holding the t/stat against the tank wall. Also, while you have the T/stat off, use a piece of emery paper to clean any rust or corrosion on the tank wall behind the t/stat mount location. The second, and surely the most common problem is in the wiring on the upper t/stat. Although the upper t/stats all look physically the same, there are two different wiring configurations used on the upper t/stats. You MUST check the wiring diagram printed on the new t/stat package and make sure the lower t/stat and element are connected to the upper t/stat correctly. The third problem is generally only seen on installation of a new water heater, but if they had reason to disconnect the power cable from the internal wiring on top of the water heater, make sure the connections were re-connected using the proper size wire nut and make sure it is a tight connection. A loodr or improper connection will result in a voltage drop, which in turn increases the amperage draw and trips out the reset button. Under no circumstances would I suggest a new water heater. What you need is either a new plumber that understands water heater wiring or an electrician to undo the mistakes.

skyclad- Let me again point out that a Pressure Reduction Valve (PRV) should not be buried and the city telling you that lines would have to be dug up sounds entirely bogus. PRV's do not last forever because they have an internal diaphragm that needs to be refurbished periodically (typically every 10 years or so). There is also an adjustment screw that you have to set to get the correct pressure, and sometimes you need to reset it if the supply pressure changes significantly. I'm not saying it's impossible that someone buried it -- in the concrete or behind some sheetrock -- but only an imbecile would do so. You may have a PRV somewhere and just be unaware of it. Or there might not be one, and you will need to have one installed. Finally, when the employee told you 130 PSI was "normal," all that means is that could be the normal supply pressure, not that it would be ok to have that pressure inside the house. Regardless of whether it's 150, or 130 or even 100 psi, as Jake said, you've got to get it adjusted down to no more than 80 psi.

@Karen Williams This is the control panel on my tankless water heater. Water Set Point ... the output temperature the unit feeds into the hot faucets ... can be set in 1°F increments between 50°F and 140°F. Temp Up and Temp Down buttons adjust the Water Set Point temperature. Then press Temp Set to make it the normal at-all-times temperature if desired ... otherwise the adjustment is temporary and will revert back after a number of minutes. I have 103°F as the "normal" temperature and raise it when needed for washing dishes or clothes, without pressing Temp Set, and it reverts back to 103°F after 30 minutes so I don't have to remember to do that. That's just how my unit works, they're not all the same. Setting the temperature "at the faucet" means I set the water heater to the temperature of heated water I want/need "at the faucet" ... such as 103°F for a shower, instead of 120°F or 135°F which is much hotter than needed for a shower ... and I turn on only the hot faucet (or set a single-lever faucet to full-hot with no cold mixed-in). Thus, the tankless unit has a high-enough flow rate passing through it for the duration of the shower to insure it doesn't shut off due to too-low flow. 120°F, 135°F, 140°F output temperature requires mixing in cold water and turning down the hot flow at the faucet to get a comfortable shower, which reduces the flow through tankless possibly below the required rate which can cause it to shut off completely and the shower goes cold. Remote control panel means exactly that ... some tankless water heaters can have an optional extra temperature control panel installed at a convenient location such as bathroom or kitchen so the homeowner doesn't have to go down to a basement or out to a garage or wherever the heater is located to adjust the temperature. My heater doesn't have a remote control but it's located in a broom closet in my laundry room behind the kitchen near the center of the house so is easy to access any time I want to change the setting.