We had an electric water heater installed after our gas water heater was put in. I am able to cut off the water to the electric as well as the output from it near where the electric ties in to the gas water heater outlet. Now, the electric is out of the loop and the gas heater is a solo unit. The problem is there is no water coming from the gas heater tank and there is water going into it. I think what ever they used to plug the output from the gas water heater while they soldered the tee in place has stopped up the output from the gas heater?? Any ideas??

Why two water heaters and why two types
If you installed a shut off on the hot water out let of any hearter it's not only illegal but dangerous. Did a licensed plumber hook it up that way? What's the nature of the "loop"? Series or parallel?
If the gas heater's fired up and gererating hot water and the outlet's plugged you have a second dangerous siutuation set up. My advice? Shut both heaters off and hire a licensed plumber to straighten this mess out. Regards, Tom

First I turn off the water to the electric. Then turn off the output from the electric.

I didn't install a shut-off valve on the electrics outlet. A licensed plumber did. At my request.

The outlet of the gas heater does not have a cutoff. It does have a cutoff on the input side for cold water to enter the tank. When the electric is in use no hot water can backflow into the gas heater because of the valve being closed for cold water input. When the gas is on and the electric is off and both valves for the electric are closed. The input valve for cold water is opened into the gas heater and the heater is fired up. This is where we run into trouble. Nothing comes out of the hot water side of the gas unit. I am aware of the possibility of trouble with the output of either heater closed or as in the case of the gas unit it's outlet being ?plugged? I don't know what has happened but I guess that the licensed plumber used something other than bread to plug the gas units output so he could tie in the electric with a tee. The tee is only about 8" to 10" from the top of the gas unit. I tried to make the water in the pipe boil with a torch hoping that would blow the plug or whatever is stopping the water from flowing. I chickened out and really didn't keep the torch on the pipe for very long. I wasn't too worried because pressure buildup could go back into the tank. When I was unable to get water flowing I turned the gass off and went back to the electric. Licensed plumber who installed the electric and plumbed the circuit will be here in the morning.