Not quite true.. we have hot water....it just won't leave the tank.
Turned on the HW bypass....cold water flowed just fine... so it had to be the tank.
Tried to remove the bypass check valve... rusted solid....
So, I looked again and began to remove the parts in place. Turn off the water outside. Open a tap and relieve all pressure...close the tap again so the lines don't siphon back to you.
Now, pull that white plastic seal out very gently. It's needed to re assemble. Use the internal pump to give a little shot of pressure... the guts of the valve should pop out.
Close inspection show that the poppet part of the valve is breaking down. I tried to clean and re assemble but it stuck again. It's now in my "parts bin" (where I keep the bits I had to remove but may need later).
So, the water is back but the water heater bypass won't work until I replace the poppet. Not a big deal to do, I just have to remember that if I go to winterize.
By the way, when you go to re assemble, the white rubber seal slips onto the flare it fitting and then is inserted into the valve...don't slip it into the valve and try to connect the flare it.....it will fold up on you.