Water Stinks with recirculation pump

carike

I had a hot water recirculation pump installed just over a year ago. Now, my water stinks when I turn on the hot water tap and I have luke warm water in my cold water line. I was told to drain off the water in my hot water tank, but this did not solve the stinky water problem. If I turn off the pump, the stinky water goes away. However, I then have to wait a long, long time to get hot water. I suspect that the hot water standing in the pipes helps bacteria to grow resulting in stinky water. Has anyone else had this problem? How do I solve the problem?

Alan

The thing with a recirc pump is..... well, the water isn't standing in the pipes.

I've actually heard before that the stink is from the anode rod going bad. Can you check the anode rod, or is your ceiling too low?

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Journeyman Plumber

Git

Not to change the subject - but we use a remote controlled switch on our recirculator to only turn it on when we want to use it. You can find something like this for less that $20. Also an X-10 module will work and I recently upgraded to some Z Wave devices that work great.

carike

Thanks for your response. I had the plumber change the anode rod. The water still stinks. Any other ideas?

I still think it is the recirc pump because my plumbing runs through the concrete floor and the plumber had to recirculate the hot water into my cold water line instead of the correct way of sending it back into the hot water tank using a line of its own. Now, I have luke warm in the hot water line and in the cold water line.

Frustrated in Ohio.

Alan

was the anode rod bad?

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Journeyman Plumber

TazinCR

Disconnect the pump for a month and see if it clears up.

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mstplumber

OK. I will keep this as short as possible but there are a couple of things to consider.

First, stinky water is usually caused by a reaction between anaerobic bacteria (present in some water supplies) and the magnesium and/or aluminum anode rods used to protect the water heaters. This reaction creates hydrogen sulfide gas, causing the classic "rotten egg" odor. If you have a water softener the problem is usually worse.

If you don't have a water softener, the best way to correct this is usually by replacing the anode rod with one made of zinc and aluminum. The zinc is critical to stopping the smell. If your heater has more than 1 anode make sure you remove the other old one or you will be canceling out the benefit of the new one. I know you have had the anode replaced already but if the new one doesn't have the zinc you need to do it again.

If you do have a water softener, a powered anode should correct your problem but will cost a lot more, $200 and up.

As for the pump, it sounds like you have a Grundfos or Lang type designed to move the cooled water from the hot pipe to the cold to keep from wasting water. These work very well but, as you mentioned, they have a tendency to make the cold water warm for a few seconds.

There is another system, the Metlund D'mand System, which is much more efficient and minimizes the issue of warm water in the cold pipes. It does this by moving the water much more quickly through the pipes. It also costs more so that is a factor to consider.

Hope this helps.

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