Howdy @rwburnett My house is built on a concrete slab and the master bath is on the opposite end of the house from the water heater. The hot water recirculation pump is controlled by a wall switch in the master bath.
I’ve taken your idea one step further. By putting the recirculation pump on a Wyze smart plug and by adding a Wyze motion sensor in the master bath, I created a rule to turn on the pump when the sensor detects motion. Another rule turns off the pump after running for five minutes.
I tried this a while back (with another plug & motion sensor). The hot water was running so long the cold water line became excessively hot. So keep enter out for that.
I gave up on it. But maybe it would work if I found a way to stop it from running more than once an hour.
Hi Brian. My situation is a bit different. The house is 25 years old and fortunately the people who designed the house included a dedicated hot water return pipe.
Hi Aaron, Years ago I installed a Grundfos pump with an integrated timer that used the cold water pipe as the return line. A special temperature valve below the most distant sink made this possible. I gave up on this arrangement because the cold water line was hot.
I reused this pump on our current house but didn’t use the diverter value. I replaced old water lines with pex (insulated) and added a dedicated return line to circulate hot water. Note: this required two check valves to keep the flow going in the proper direction.
I could set the timer pins on the pump but I prefer to control the pump only when needed. So I added a smart switch controlled by Alexa. “Pump on” or “Pump off” 4 minutes of run time gives me hot water by the time 2 cups of water has passed. Sometimes I’ll forget to turn off the pump.
Next, I’ve played with the timer feature on the smart plug but haven’t found a solution to have the pump turn off after 5 minutes by default. Have you figured out a way to do this?
I have a Grundfos as well, and use a motion sensor to tell Alexa to turn the pump on, and then time it for 5 minutes then off. It works amazing. I do have check valves installed at the cold water feed line to the water heater, and I have bypassed the old-school timer and temperature switches built into the pump and wiring.
Thanks Mark for your post. Do you have more than one motion sensor controlling the pump? In my case, I use hot water in two bathrooms, a laundry area and the kitchen. My goal is to have hot water after one cup of water has flowed from any faucet.
I monitor the temperature of the cross over line in the bathroom. When it hits around 95 I end the cycle by shutting off the pump (Samsung plug) and close the valve on the cross over line. That seems to work well for me.
I ran into the same problem of the cold water getting hot. Ran a pex dedicated return to the hot water tank, the house is all copper water piping. This was before even knowing about Wyze products. It is on a schedule set at pump. Now I am going to add a Wyze plug and try t his when I get my Cameras all installed outside.
Sharing what I did with my hot water recirculator. This will work with just about any pump.
This is what I did to turn my hot water recirculator on for a designated period. I created an Amazon Alexa routine (listed below) which I called Hot Water. When I say “Alexa, Hot Water” it runs the routine.
Say “Turning on the pump”
Pump – power on
Wait 5 minutes
Say “Turning the pump off”
Pump – power off
You can also schedule the routine to run at a specific time (e.g. right before you get up in the morning). I prefer to simply tell Alexa when I want hot water and our schedule is not always consistent. I think this also can be done with a google home routine by saying/adding something like “turn on the pump for five minutes” but not entirely sure as I don’t use google home as my main smarthome portal.
Also, if the recirculating pump is in a unconditioned area (garage, attic, etc), I would recommend using the outdoor plug as the specs for the temperature range are broader than the indoor plugs.
I’ve tried to create a simple timed event where google home will turn on my recirc pump and turn it off in five minutes. Google home doesn’t seem to allow a timed event on appliance type controls (non- light bulbs) for safety reasons. Any advice?