It probably runs near a heat vent and the water warms up when it's just sitting in the pipe. It will probably cool after you let it run for a while and start bringing in the water that was outside, underground. Depending on your area, underground water seeks ground temperature and that's what you should be getting after you let the water run for a little.
Yes, it can also cross through a two handled faucet. Both the hot and cold sides of the faucet must be on and the flow of water must be stopped or greatly reduced on the outlet side of the faucet. This can occur when a hose with a spray nozzle is attached to a laundry tub faucet with the faucet on and the spray nozzle off, or when a shower faucet is on but the shower spray head is off. When another cold water outlet in the system is turned on then the pressure on the cold side of the laundry tub or shower faucet in question could be lowered below the pressure on the hot side and hot water can flow into the cold water side. There are faucets which have integral check valves which prevent this from occurring. WWW.WOODBRIDGEPLUMBING.COM
Yes
cold water tub facuet is corroded bye hard water builtup and needs to be replaced. Hot water is okay. Its the right one with the cold water coming out
If water is only drawn from the cold faucet, then no, the water heater is not involved. However, if water is drawn from the hot faucet- even for a few seconds- hot water IS withdrawn from the heater, and fresh cold water drawn in to be heated- even if the hot water did not make it all the way through the pipe to the faucet- and the water heater will work to heat that fresh cold water.
If you have nothing coming out the faucet, your lines are probably frozen somewhere. The lines could develop leaks, so be watchful when they thaw.
true, the water is going to get hot either if you use cold or hot water You did not answer my question of if it was "true" or a "myth" that the water had to be from the cold water faucet. From what you did respond to it sounds as if the question I generated means it is a myth that the water "has" to be from the cold water facuet.
its not the co.pper line its the faucet stem or angle stop
The part the water pours out of, usually activated by a lever in houses (perhaps one for cold water, one for warm water) and sometimes in public bathrooms. However, it is common for restaurants to have automatic hand sensors that generate the faucet. Otherwise, you could look "faucet" up in a dictionary.
Kitchen faucet? If so, the sprayer attaches to the underside of the faucet in the middle.
Possibly a pressure reducing valve installed after piping for first faucet, which would cause situation describing.
because there no backflow perventer on laves and toilets
Possibly a cross connection