Water Recirculation Line and Recirculation Pump
Recerculation line or recirculation pump are both to create a method for few purposes. First to save energy and bring up the efficiency of the house, in fact save money. Second for convenience and having hot water right away when you open the tab. Third not wasting the water to the drain in fact pollute the environment.
Recirculation (recerc) line
By the city by law code if the hot water line is longer than 30 meter, it is mandatory to have recirc line at the house. The type of the tank is also important how to do the recirc line. Most of the indirect tank has the spot for to connect the recirc line. Not all the tankless have the option of the recirc line, but some tankless like Navien some of the unit has the facility for it. In this case, one line from the recirc line of the water unit goes to the closest possible to the tab and have it connect to the hot line. The line continue to the all the tabs where has the hot line. For that, always the hot water is available to the tab.
The normal hot water tank will get the recirc line from the hot water tank drain. A T will be installed on the hot water tank drain, so still the tank will be useable for the drain while it will be used for recirculation line.
The recirculation pump is the most practical solution. In the case of finish houses almost not possible to run the recirculation line. A special pump with a kit of check valve will be sold at the plumbing store. The pump will be installed on the hot lie of the water heater and the check valve will be installed at the furthest tab between the hot line and the cold line. In case of the running the pump without using the hot water, the hot water goes through the cold line and back to the hot water tank.
All the recirc pumps have a sort of controller, when turn ON or OFF. Either a timer that it will be set to the time of the suing the pump. For example the pump can start form 7 am for 1 hour then off and get on 4 pm ON till 8 pm or any time that can work for the family. Some of the pump are smart, first works 24 hours then it find a time not used at all then turn off automatically. Some of the pump has motion sensors. The sensors will be installed at the tabs area. And after 30 min the pump get off.