Odd situation happening. New 20 gal low boy. Side outlet and inlets. The cold water is at the side bottom, of course. This is for a small one story office on a slab(rented). Lots of old faucets and other old water using fixtures that become points of concern (bldg is over 40 yrs old), so there is a master cut off in the mechanical room. The water supply is cut off every night. The old water heater was a top inlet/outlet and this didn't cause a problem. For various reasons, a new smaller WH with side inlets was installed. (the old WH couldn't be removed due to the fact that the previous owner built cabinets around and above it. go figure.)
So what happens is, when the master water valve is cut off, it appears that the full tank of water pushes the water in the tank back through the cold inlet pipes, when a faucet is turned on. You can feel the CW pipes get warm as the tank water flows back through the inlet piping. To me this shouldn't be possible. Like a hole in the bottom of a sealed water jug. You need the an opening at the top for the water to really flow. Is this remotely possible?
Now, If you take the new WH out of the loop by closing the CW inlet valve , and turning off the bldg. master valve, there is no flow at any faucet. Just like before.
So what happens is, when the master water valve is cut off, it appears that the full tank of water pushes the water in the tank back through the cold inlet pipes, when a faucet is turned on. You can feel the CW pipes get warm as the tank water flows back through the inlet piping. To me this shouldn't be possible. Like a hole in the bottom of a sealed water jug. You need the an opening at the top for the water to really flow. Is this remotely possible?
Now, If you take the new WH out of the loop by closing the CW inlet valve , and turning off the bldg. master valve, there is no flow at any faucet. Just like before.