Dedicated hot water recirculating heater

[jasonbyer]

I have a new construction home and put in a dedicated hot water return line. It starts at the hot water heater goes around the house and back to the hot water heater.

The hot water source is an electric on-demand heater. Gas is not an option. I am on a well with a constant pressure pump set at 60psi.

I installed a recirculating pump to keep the water in the pex lines warm. https://www.supplyhouse.com/Grundfo...-115V-Pump-w-Auto-Adapt-Line-Cord-1-1-4-Union

However, the pump was coming on every 60 seconds which was causing a big spike in energy usage.

I want to get feedback on having a dedicated hot water tank that keeps the line warm so that the on-demand heaters are not running constantly.

I have about 4 gallons of water in the 3/4" hot water line running around the house. The water loses 9 degrees making the trip around the house.

My thought was dumping this 9-degree cooler water into a larger and insulated hot water tank would reduce the cost to keep the water warm in the lines.

If the hot water recirculating pump is running constantly pushing water through the line and a hot water spigot is opened causing the well to push in more water will the check valves struggle to work together causing my hot water recirculating pump to work harder or burn out?

Here is a diagram. Really appreciate the insight.

 

[breplum]

Just use a small electric water heater. You will still be using a bunch of power to keep it hot but it will work. Pipe your on demand outlet into the cold side of the WH. One check valve on the cold inlet on the on demand should do the trick.
Better idea, avoid the small WH and keep what you have and use ACT D'MAND system with pushbotton at every bathroom and kitchen or motion sensors to trigger on demand for the recirc, you will save a lot of money in the long run.
https://www.hvacquick.com/products/...ND-KONTROLS-ACT1-Hot-Water-Recirculation-Pump

 

[breplum]

You could consider this cheaper system but I have no exp with it.
It activates the pump only when you open a tap to start the pump
The Smart Recirculation Control 32 is an "On Demand' flow meter based recirculation pump controller designed to sense when hot water is drawn from any plumbing fixture and run the recirculation pump until the water in the recirculation loop is hot. The microprocessor based design monitors the temperature of the water in the loop using a unique dual temperature sensor design to ensure the water in the loop stays hot while hot water is being used.


https://www.ebay.com/itm/3328296072...Frwp3UkDA1b5Xw%3D%3D|ampid:PL_CLK|clp:2047675

 

[jasonbyer]

Thanks for the ideas @breplum

 

[frontporch]

based on your diagram, shouldn't your recirculating pump loop include the instant hot water heater? As is you are pushing around unheated water.

If the diagram doesn't represent the actual situation and you are having issues with the pump, can you set it to a timer? Get hot water in the line at 7AM?

Your link for the pump also had some reviews where somebody talked in some detail about overcoming shortcomings in the pump and how it determines when to run. Might want to see if any good guidance there.

 

[jasonbyer]

thanks @frontporch I'll read those pump reviews.