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Recirculating for Tankless Water Heater

We have a tank less water heater, it works well, saves gas, but there is a lot of water waste while we wait for hot water at the far end of the house. We are in California, have a major drought going in need to do something about the water going down the drain. When we had a regular 40 gallon water heater we had a recirculating pump and it worked fine. We were told that we couldn't use the pump on the tank less heater. Does anybody know of a device or method that can do the job for the tank less heater?

Re: Recirculating for Tankless Water Heater

There us a device you can install under each sink that will send the not -yet-hot water back to the HWH until the proper temperature is reached.

Not sure what they are called.

Re: Recirculating for Tankless Water Heater

Generally, you can not and do not want touse a recirculating system on a tankless heater. The reason being that it would require the tankless heater to run continuously defeating the savings on gas. Perhaps you should consider a point of use heater.


Re: Recirculating for Tankless Water Heater

Both good answers.

Re: Recirculating for Tankless Water Heater

It doesn't seem a problem what kind of DHW you have if you have a re-circulation pump attached that is triggered by a push button. I have one in the new and farthest bath. When I go to take a shower I push the button on the vanity and when it stops I have hot water at the sink. It only runs when I want it to, no waste water down the drain, less in the septic, less from the well. Lots of wins and only minor electric use while it runs.

Re: Recirculating for Tankless Water Heater

A recirculation pump does not work well with a tankless water heater. Since tankless heaters are demand-sensitive, they would fire whenever the pump is running.

There is a hybrid tank available that stores only a few gallons of heated water, but is still able to meet continuous demand for water. These do work with recirculating pumps. One was featured on Season 12, Episode 5 of Ask This Old House.

Link to video: http://www.thisoldhouse.com/toh/tv/ask-toh/video/0,,20750181,00.html

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