SmartThings Community

Can I have 2 switches turn on/off a plug that is also on a timer?

(Martin) #1

I am wondering if can do the following with SmartThings.

I have a circulation pump for my tankless water heater. It is currently on a manual timer and runs way more than I’d like. I’d prefer to plug it into a z-wave outlet that is turned on less of the current time but will also turn on when the one of the two bathroom fans is turned on. If the pump was in an off-time-period then it would turn on and off with either of the fans. Can this be done at all? (See sample timeline below for clarification.)

Can I use any z-wave switches on the fans and have the hub trigger the pump outlet when a fan is turned on off, or do I need switches with specific features? (I’ve read something about the need to poll some switches because they don’t send a state change message? That seems sub-optimal.)

Thanks for any guidance/recommendations you can provide. Which reminds me, do you have recommendations for which outlet & switches to use for this?

Here is an example timeline:
7:00a pump on due to time
8:00a fan-1 is switched on, no change to pump
8:30a fan-1 off, no change to pump
10:00 pump off due to time
1:00p fan-1 on, pump turned on since not already on/not during on time
1:30p fan-1 off pump turned off

5:00p pump on due to time
7:00p pump off due to time

10:00p fan-1 on, pump on
10:15p fan-2 on, pump stays on
10:20p fan-1 off, pump stays on because fan-2 is on
10:15p fan-2 off, pump off


I think this can be done with Rule Machine, which is a custom code rules engine. Although you may have to make multiple rules.

If you haven’t already, start by reading the FAQ on using custom code with smartthings. (This is a clickable link.)

Then if that seems like something you’d like to do, ask exactly the same question in the rule machine logic topic and someone there will be able to tell you if it’s easy to set up.

Also, since you asked for suggestions on switches and equipment as well, I’ve set this up as a project topic for you so you can get additional help brainstorming complete solutions.

(Brian Diehl) #3

Could definitely be done with Rule Machine using multiple rules (since you can only use 1 time based capability per rule, you’d need multiples there).

(Martin) #4

Thanks for the pointer on Rule Engine! It looks like I can do what I want.

I’m still looking for any recommendations on what switches or outlets to use? I care most about reliability.
GE? Leviton? other?

What criteria do you use when purchasing devices to use with ST?


What are the specs on the pump? Horsepower?

(Martin) #6

It is a Grundfos 96433895. Link
Motor: 25W, Single Phase, 115V, 0.23 A


OK, that’s 1/33 horsepower, so pretty much any small appliance switch (but NOT a light dimmer switch) should be OK for the pump, but check the ratings to be sure.

As far as the pump, Are you looking for a wall switch or a “pocket socket” (plug in module)? Or to actually replace the in wall receptacle?

(Michael) #8

I am doing something similar with my circulation but but instead I have a GE Zwave on/off switch on my shower light that triggers it. I have a GE Zwave receptacle that my pump is plugged into that turns on/off when my shower light is on. I use Smart Lights for the shower light trigger so it will run locally with my v2 hub.

I also have an Amazon Echo setup where I can tell it to “turn on hot water” and it will turn on the pump. I also have a SmartApp that kicks in when the light and pump turn on and will automatically turn it off after 90 minutes if it is still on since my wife often forgets to turn off lights.

So definitely doable

(Martin) #9

@JDRoberts I was thinking I’d replace the in-wall receptacle or use a module to plug into the existing receptacle. When I’ve looked at modules the Aeon Smart Energy switch seems to get good reviews on Amazon. Would people here that are “in the know” recommend it? As I said earlier, reliability is my main concern. I’d rather not have to replace something because my initial purchase was occasionally not working. That thought makes me wonder if using a device like the newest Aeon is better in any practical sense (with it’s newer z-wave chip) vs the older one that is much less expensive.

OTOH, it seems SmartThings is mostly selling GE stuff. Maybe that is the best choice since they obviously will ensure that it continues to work well if they sell it?

@ritchierich Sounds pretty similar indeed. I plan to use the fan switch instead of the light switch since there is no specific “shower light”. Also, as I mentioned, I also want timed operation so that the pump is running during dinner prep, and 1st thing in the morning so there is no delay on the early morning shower.

(Michael) #10

@Mog you can still manage the morning schedule with Smart Lights too in addition to what I described. If you have a v2 hub these will run locally which to me has been a little more reliable.

(Martin) #11

@ritchierich I have purchased and installed a GE on/off switch and an AEON Smart energy switch.

Using SmartLighting I have two automations to turn the pump on and off during the morning and evening. This works as expected. I created a third automation that turns on the pump when the bath switch is turned on and left the “turn off as well” selected. This will turn on the pump when it is not during a scheduled on-time and off when the switch is off. However, it does not do what I want when the switch is turned off during a scheduled time. In other words, if the pump is on during the morning schedule and I then switch on the light/fan, it continues to run, but will turn off when I turn the switch off even though it is still during the time when the pump is scheduled to be on.

I’m thinking that managing this “state” is why @JDRoberts and @diehllane suggested using Rule Machine. I like the reliability of running SmartLighing on hub, but am not sure how to make it work with just that SmartApp. Am I missing something?

(Michael) #12

@Mog in your 3rd SmartLighting app, scroll to the bottom and click more actions and there you can set it to run at certain times. That should hopefully do what you want.

(Martin) #13

Thanks @ritchierich. I had opened the 'More Options" earlier but had forgotten what was in there when I had the problem.

That said, I don’t see a way to do multiple time periods. I have the pump on in the morning and again in the evening. It does work to tell the switch automation to not run during the pump’s morning hours, however I don’t see a way to say don’t do anything 7-9a and don’t do anything 5-7p. Am I missing something else?

(Michael) #14

@Mog you aren’t missing anything as Smart Lights will only allow one time period. You can use Rule Machine instead, though it won’t run locally like the Smart Lights does.

(Martin) #15

Just to wrap this up. Everything is now working as I’d hoped.

I use SmartLighing to turn on/off the pump in the morning and evening. I use Rule Engine to turn the pump on when a fan switch is on (only one fan switch at the moment). I see that the timed routines run locally as was recommended.

I also added two virtual switches to turn the pump on for 5 or 30 minutes (using ‘Turn off after some minutes’ SmartApp) whenever my wife wants to save water but have it hot. ( I could have done the delay with Rule Engine as well I suppose.)

I’ve had no failures/mis-fires with this setup so far.

Thanks for the pointers and advice @JDRoberts @ritchierich