I have a kitchen faucet that allows water to back flow through the pipes. The way that works is that you turn on the main faucet handle to warm water, then turn off the water at the at the faucet and don't use the sprayer. The faucet in question is this one.
When the main faucet handle is on warm, but the faucet is off, it allows the hot and the cold water to mix. I notice this for example when a hose is turned on outside. I hear water flowing through the kitchen faucet. I think that means that the hot water is getting to the hose through the kitchen faucet.
I can prevent it by turning off the main kitchen faucet. I can also prevent it by having the water temperature set to full hot or full cold at the kitchen faucet, even with it turned on. We'd like to be able to leave the water turned on warm at this faucet so that the sprayer is available easily.
I was thinking that the solution could be check valves. Are there check valves I could install myself, like ones that screw onto the supply lines?
How do I solve the hot and cold water mixing problem at this faucet?