Tempering valve

[tuffun]

Just got a new tempering valve for the house. Planning to move the water heater to a new loc. in the basement as it is and with the 3 kids burning
up the water fast, it makes since to put it in now.

Lazy - would it be possible to give me a quick diagram of how to put it in?
It's a Watts 70A - 3/4in. (whether this matter in the schem.)

The diagram they sent shows 2 other valves added to the system (vacuum relief valve on the inlet cold water -- T&P relief valve on top of the tank.) Along with 1 hot water to appliances and 1 tempered water lins added.

Is all this neccessary? I was possibly wrongly under the impression from the info I'd read that it was 3 connections without the additional valves and line diversions. Thanks for the help.

http://home.wi.rr.com/smhome/Desktop-1.jpg

[LazyPup]

Tempering Valves are not commonly used in residential applications therefore the illustration in the post is depicting the use of a tempering valve in a commercial application.

The principal difference is a result of health code regulations and the differences between residential and light commercial undercounter dishwashers such as might be found in your local neighborhood coffee shop.

Residential dishwashers have a heating element for the dry cycle which can also be used to heat the final rinse water to the prescribed 180degF sanitizing temperature. In residential application it is also common to use a chemical sanitizing agent thus negating the need of the 180degF water thus most residential dishwashers have an "Energy Saver" function that turns the heat off during the final rinse and sanitizing function.

Most light commercial dishwashers do not have the built in heating element but rather they rely upon a 180degF water source which explains the "Appliance Line" in the illustration.

(You local health inspector has a small tube of paste that looks like tooth paste that is a temperature sensing agent. When testing a commercial dishwasher they apply a small amount of the paste to a cup or plate and run it through the dishwashing cycle. If the rinse water is 180degF or greater the paste will change colors giving a visible confirmation that the unit has the proper sanitizing temperature.)

The Residential Plumbing Code limits the maximum permissible temperature on the domestic potable hot water system to not more than 140degF and tubs or showers are limited to not more than 125DegF. Generally in order to meet code compliance we simply set the water heater to 125DegF.

The Residential Plumbing Codes make allowance for the water heater to be operated at a higher temperature such as when a water heater is used for both domestic hot water and hydronic space heating, providing the output to the potable water system is regulated to the above mentioned temperature limits.

The layout shown in the illustration in the first post is the method for installing a tempering valve when you require both the 180degF water for space heating or a commercial dishwasher. When it is desired to operate the water heater at a higher temperature solefy for the production of residential potable hot water the Hot water outlet from the water heater is connected to the hot water input side of the tempering valve. The incoming cold water line is then Tee'd with one line providing the supply water to the water heater while the second line is connected to the Cold Water input side of the Tempering Valve. The main line to the House Potable Hot Water system is then connected to the output port of the Tempering Valve. I have prepared & attached an illustration on how to install the tempering valve for a residential application.

While it is not commonly done there are some local codes that require the installation of a vacuum Relief Valve such as the Watts N-56 valve shown in your installation. (check local code requirements).

The Plumbing Codes require that a Temperature & Pressure Relief Valve (T&P Valve) must be installed in the upper 6" of the water heater vessel. Typically they are installed on the top of an electric water heater but due to the space requirement for the flue they are generally installed on the side of a gas fired water heater. Here again, some local codes require that all T&P valves must be installed on the top of the tank. In that case it is common practice to install a Tee on the output port with the hot water line on the side outlet of the Tee and the T&P valve on the top of the TEE. The problem with this configuration is that it raises the T&P valve up which places the sensing elemet above the normal water level of the tank in the TEE. In this case it is necessary to use the WATTS 100XL type T&P valve. (The XL indicates an "extra long" sensing element.