We just had two 50 gallon electric water heaters installed inline. Rheem professional classics. And a new check valve.
The check valve was for the circulating pump. They had to leave the old one on. They said it was stuck in an open position. There's little tank connected in case something goes wrong--the tank takes some of the overflow. It is connected to the water heater pipes.
When we take a shower the water fluctuates between mildly cool and a little warmer about every six to eight seconds. This is for the entire time we shower. It is not like when you flush a toliet. It did not do this before the new heaters were put in.
They did put a little tank on top to the side of the new heaters. We have had them out three times and they can not fix this. Do you know what is causing this? Help.