I am planning to improve my bathroom by installing a bidet. I do not like the idea of cold water and I am planning to add a mixer to constantly get lukewarm water.
Proposed plumbing scheme:
- Insert a three-way elbow pipe (with valve for emergencies) to cold water pipe, and second one to hot water pipe.
- Connect a water mixer (either with or without a thermostat) to hot and cold water.
- Connect a bidet hose with a button on the end to start the flow.
My plan is to hide the water mixer in a wall behind inconvenient mini-door and keep it in opened position with 20%/80% hot/cold ratio (lukewarm) and control the bidet only using the button on the hose. This means mixer is being constantly open and I am afraid that when bidet end valve is closed and mixer is still on, hot and cold water might start to mix in the main pipes. Is this true?
Also, a follow up question, is the mixer even necessary in this situation? Couldn't I control the flow and the temperature by opening the hot water valve in three way pipe by 20% and cold water in the three way pipe by 60%, join those pipes and connect to the bidet hose without any mixer? The hose is 100cm long, so water should mix properly, I am just wondering is there some additional mechanism in the mixer to prevent water going opposite direction when opened, but output closed?