Thank you for you question. Because Watts is such an old company they essentially use two distinct numbering systems. The problem is that some literature uses the old, some use the new and some uses both. Every Watts product/SKU now carries a unique and distinct number. Watts refers to that as there EDP code. Every variant created by options or size would have a different EDP code. In this case that number is 0100156, Then you have the traditional numbering system which in this case would be LFTWH-FT-HCN-RV. This number number can be decoded to let you establish basics about the product but it is not uniquely discrete. Meaning for example that same traditional number could be available in a number of different sizes. As to the other part of you question this tankless valve kit comes with a relief valve manufactured by Watts. The EDP code on that valve is 0556050. The traditional nomenclature is 3/4" LF4L-150. The "LF" indicates lead free brass and the 150 indicates the pressure rating at which it will blow off. 150 PSI is essentially standard for residential potable water heaters. It does not have a temperature probe similar to the ones found on tank type hot water heaters such as the Watts 100XL. That is because tankless water heaters have little to no stored water so they use a different style of relief. Again thank you for your thoughtful question . We will ad the specification sheet for the relief valve for the benefit of others moving forward.
To begin, a system where water is heated for potable applications is not closed. It is open. When you turn on a faucet you are opening the system. Further potable water, aka drinking water, contains oxygen. Again this indicates that the system is open. Closed loop systems stay closed and use oxygen depleted water over and over again. the most common would be a hydronic heating system where you have a boiler that heats the same water over and over again and uses that water as a heat transfer liquid to heat the structure. Second thermal expansion tanks that are on water heaters and hyrdonic expansion tanks that are on boilers, are not hammer arresters. Granted in some applications they may ironically mitigate hammer but that is not there intended purpose. Water hammer is absorbed by a hammer arrestor place hear the source of the hammer. The source of the hammer is typically a quick closing valve, such as the solenoid valve used in a washing machine. The source is typically not a water heater. Although some newer style heaters do have quick closing valves so I do discount the possibility. Hammer arrestors can mitigate the system but the best solution is to fix the problem, either by reducing the pressure, properly securing the pipes or both. So if thermal and hydronic expansion tanks are not hammer arrestors, What are they? . When water is heated it expands. That is a law of physics. Boilers typically operate at 15 PSI. At 30 PSI the pressure relief will blow off. In order to prevent the pressure from rising the system needs the ability to get bigger and smaller depending on the temperature of the water This way the system pressure will remain constant. In the old days they would use something similar to the overflow in an automobile radiator. Expanded water would leave the system and then get sucked back in was it cooled. However this essentially makes the system open and can allow air in. As air will corrode the ferrous metals boiler engineers invented the expansion tank. A tank with a diaphragm across the center. On one side is the system water and on the other and inert gas. As the boiler is heated the expanded water pushes against the diaphragm making the system larger, When it cools the gas on the other side of the diaphragm pushes it back into the system. The internal system pressure remains constant and the system remains closed. Thermal expansion tanks are different from boiler expansion tanks in two major ways. First any ferrous metals used are coated so that the oxygen in the system does not cause them to rust. Second pressure on the gas side of the diaphragm is much higher because domestic water supplies are are much higher. Thermal expansion tanks essentially did not exist until the 1990's Why? because they were not needed. When water inside the heater was heated it would simply expand backwards into the street and forwards into the house. However two changes took place. Due to legionnaires disease pretty much every water meter in this country was changed. Check valves were added so that water could not move backwards once moved by the meter. Second faucet technology was up ended by the emergence of the ceramic valve cartridge and the rubber washer went the way of the dinosaur. These valves have no give . The result, the expansion of the heated water could not be absorbed by moving forward or back. Thus pressure builds. If your base line cold water pressure was abnormally high, such as mine at 105 PSI, once heated it could reach 150 PSI. When this happens the pressure relief will burp. The pressure is relieved by the removal of hot water which is instantaneously replaced by cold water. Then that is heated and it burps again. The solution was the thermal expansion tank. The air pressure on the gas side of the diaphram is matched to the cold water supply pressure; this positions the diaphragm appropriately for that home. Now when the heated cold water expands the system has a space available to accomidate it. The result? pressure remains constant. The sad part is that in most applications the gas side of the tank is never matched to the cold water supply pressure so the vast majority of thermal tanks out there are doing nothing at all; except satisfying the inspector that wants to see one in every installation because that is what the code book says. As to installing one on an instantaneous heater. As there is no stored water and the water that is heated is so minute in quantity I cannot see the logic. However I am sure there are inspectors that will insist on them. The irrational requirements and interpretations of code made by some inspectors have never ceased to amaze me. Lastly you mention a pressure regulating valve. These comes in many varieties. I assume you mean a pressure reducing valve. If so you should be able to set the out put pressure to something nominal and consistent. Then based on the BTU's of the heater and the quantity of heated hot water storage, size the thermal tank appropriately. However keep in mind. pressure reducing valves work well and for a long period of time when water is running through them and they are in operation. However it is not uncommon to have water leak through them when the faucets are closed, after about a year. Thus if the system has a gauge you will see the system pressure rise when the system is off. Then as soon as you open a faucet it drops to the set point. The you shut the water off and it slowly starts to rise. Best of luck. Chris 9786513301
You will need to buy a 1/2 inch to 3/4 inch bushing to do that.
Use copper pipe. Mike
I WOULD GUESS YES, THEY ARE USED SO YOU CAN FLUSH,CLEAN OUT WATER HEATER, SO I WOULD WANT THEM WITH A NEW WATER HEATER.
Too much tape and maybe you should have used a GOOD pipe dope on the fittings instead ? just a thought but I think 5 wraps with T Tape is too much
Well Orville the reason for the water flow valve is it has a water port you can run a cleaner of sort to clean out your tankless water heater once a year, if you have hard water or more. I don't know if this was the answer you were looking for.
Well Dr standard pipe fittings nipples, elbows and what every it takes to make it work for you. I might suggest using Pex plastic pipe(comes in three colors) and Sharkbite fittings for your hook up . The pipe is stiff but will bend some what and easy to work with, it can be cut with a tubing cutter or a hack saw The plus side the fitting can be taken off the pipe with a special tool if you have to redo the fittings hook up, to long or to short, your Home Depot pluming guy can set you right up, don't forget pipe dope or fitting tape. Make sure you add a in line filter to your hook up if you thank you need it. good luck 86
Looking into Pex plastic pipe and Sharkbite fitting sold at Home Depot lot easier then metal pipe!