I have a Grundfos hot water circulator. After turning off the main to the house and the hot water circulator the other day to change out a valve for our dishwasher, the hot water circulator hasn't been working properly (making horrible noises, not sending out water properly).
From what I've read it seems that the hot water circulator has seized. We've unplugged and replugged, and tried to turn the bolt on it, but it won't move. Again, from what I've read, this indicates we probably need to replace with a new unit.
My belief was that we would still have hot water (as we would if we didn't have a circulator), however we are not getting sustained hot water in our showers both upstairs and downstairs (after about 5 minutes the water is warm, but then turns cold). What would cause that? I am hoping to figure out how to have hot water access until we can get the unit replaced.
Best Answer
Pressure from the cold side is higher than from the hot side, so cold water is backfeeding through the circulator and on to the hot side to the faucets in use. Close the shutoffs you have for the circulator and the problem should go away.