I added a full shutoff valve and a one way valve on the hot side which is similar to the kit shown only cheaper. It didn't fix the problem. The real issue is inside the Girard water heater. There are two safety devices, a flow sensor and a temperature sensor, that take time (and water) before the unit will re-ignite and heat the water after a shower turn off. My Atwood gas heater with 1400w electric rod "almost" acts like a tankless when both gas and electric rod are turned on.