We have a fairly new (2 years) water heater. It has begun to vary widely in temperature. Sometimes (after a long period of no use) the water is fairly cool.
While taking a shower we have to use hot water only. Other times (also after a long period of no use) it seems to be the correct temperature which is about
120 F.
I don't think it did this when new. What could be causing this?
I don't think it did this when new. What could be causing this?

