Tips on Managing a Hot Water Recirculation Pump


(John Goodin) #1


Newbie here, but enjoying the learning experience…

I’ve reviewed some of the other recirc pump ideas, but not finding my same application.

I have a 120 V digital Intermatic wall switch timer that I want to use to activate a remote hot water recirculation pump in my garage, so it can run for 30-45 seconds when activated. When I turn the wall switch timer on, I want to activate the pump and then have the pump turn off when the timer runs out and shuts off. I need a z wave momentary contact type device that sends a signal to the pump outlet when the timer turns on and off when the timer runs down. I tried the Linear fixture contact device, but can’t make it work through the standard ST hub. Perhaps a smartapp or ??? Or a more appropriate Z wave device to make this communication happen between the wall switch and pump? Thanks for any insights!

(Matt) #2

could you do this. Z wave outlet controller on the pump and a thermal sensor on the far end of your hot water line. When it hits the desired temp it fires a rule in rule machine to run the pump for 1 minute and turn it back off

(Frank ) #3

I use the smart lights app for a timer. I leave my pump run for 10 minutes after it’s been triggered. The pump is controlled by a zwave appliance module, as my heater is on a gfi, and I didn’t want to modify the circuit. The downside is a wall switch won’t operate it, but I have several minimotes, voice control, and app control.

(Matt) #4

Here is what I am going to do.
1 Smartsense appliance outlet hooked to the pump
2. Monoprice Open/close sensor with its screw terminals hooked to this

  1. A little thermal wrap from Home depot to hold the temp probe on the pipe.
  2. set an open/close rule so that when the contacts open it starts the pump and when they close it shuts off. you could limit it to modes or time of day if you wished.

quick easy and functional.

(Brian) #5

I may not understand your applcation, but I have my recirculation plump plugged into a GE outlet that goes on and off based on presence.

(Paul) #6

My hot water recirc pump was my first integration on ST, and it is still my most reliable. (By which I mean it works about 98% of the time. When it fails, it fails in the “on” position, which is wasteful but not horrible).

I have contact sensors on my bathroom doors, which trigger the pump to run for 30sec. I’ve been meaning to update the app that ties it all together for functionality and reliability, but I’m out of town for another week and a half. If you can wait that long, I’d be happy to post it here once I have it cleaned up and tested.

(Matt) #7

my application is to keep the water warm all the time :smile:
but having a thermal sensor on the furthest end of the hot water pipe I can trigger the pump to turn on when the temp drops below a preset (In this case 102F 40C) temperature. with that preset the water in the pipe stays at about 115 all the time. I can set it to only run when I am home or just during the day when we are awake. In short I forgot about the timer and just trigger the pump with the thermal sensor and the appliance outlet (or you can use your GE wall outlet to do the same) just turns on the pump on its end

(John Goodin) #8

Excellent input everyone. I like the temp sensor idea. Seems straightforward and lower cost. Will pursue this option with the open/close sensor option. Much appreciated!

(Matt) #9

make sure you put the temp sensor on teh metal line on the line after the hot water valve.

(John Goodin) #10

Will this thermocouple you suggest operate with low voltage say 12 V? Thanks!

(Matt) #11

it needs no voltage. it will operate off of the open close sensor no need for separate power for it

(Matt) #12

basicly it is tuned by the content of the sensor to open or close depending on temperature. it does not require any voltage

(Paul) #13

@keltymd have you gotten your temperature probe setup to work? I bought one of those temperature controller switches and attached it to a spare contact sensor. My tankless hot water heater is set to pump out 125°F water, but the pipe never seems to get hot enough to trigger this switch. Not even after a 15 minute shower. I confirmed it with a kitchen thermometer, and unfortunately the copper pipe just doesn’t get hot enough.

I might try some heat sink compound to see if I can get a better reading.

(Matt) #14

I found three things.
1, make sure it is right no the copper pipe the writing side of the sensor away from the pipe.
2. Wrap the sensor part completely with tape
3. I run my heater at 140± my last line is about 70 feet from the heater and I dropped to a 35c sensor to get it to close.

It cycles usually 2 minutes off 1 on when it is 30 or colder outside. in the 50s it runs about 1 minute every 10

(John Goodin) #15

Keltymd’s temp sensors off amazon work great for me. I placed them as breaker between the power from my timer to the relay that actives the z-wave contact switch. The temp sensor prevents the HW pump from activating if someone (my wife) comes in after me and turns the timer on for the pump. If line is already hot, the timer won’t activate the relay and restart pump.

(Paul) #16

Can you link to the 35C switch? I can only find 40C and higher.

Mine is installed like yours, but my heater is set lower. this may be a lost cause. In the meantime, I have it set up with logic that keeps the pump from running more frequently than needed, but it’s guessing.

(Matt) #17

I had to go to fleabay for it. Look for KDS9700 35c or 30c whatever temp you want

(Paul) #18

Thanks. I didn’t consider eBay. I’ll check there.