Motion Sensor Hot Water Recirc Options??

[jahmes143]

We have a new Navien on-demand water heater (NPE-240A2) with built in recirc pump. We have a dedicated recirc PEX line throughout the house. Navien has a "HotButton" accessory which adds a hard-wired button in each bathroom/kitchen. You press the button and the recirc pump turns on. The house is low-voltage pre-wired for this. Instead of the HotButton, we'd like to add motion sensors. We'd prefer to use the existing hard-wired low voltage lines rather than a wireless option. We like a "dumb" house, with no WiFi, automation systems, etc. Do you folks know if this is possible?

 

[Reach4]

From what I read, "HotButton" uses wires. I would think you could use a motion sensor with dry contacts instead of, or in parallel with, a push-button.

I guess you are wishing the motion sensor would be powered by the wires, and a common motion sensor would need a source of power.

A battery-powered security sensor might be suitable. This may involve more searching and dollars than you want to use.

 

[Sponsor]

 

[Fitter30]

From what I read, "HotButton" uses wires. I would think you could use a motion sensor with dry contacts instead of, or in parallel with, a push-button.

I guess you are wishing the motion sensor would be powered by the wires, and a common motion sensor would need a source of power.

A battery-powered security sensor might be suitable. This may involve more searching and dollars than you want to use.

One thing i would check. Hot button probably has momentary contacts. Don't know how the hot button acts with a closed contact that stays closed for a minute plus. Could wire a time delay relay set for a few seconds every time a motion sensor calls. Would probably need a relay to take that signal wire for control because it will be putting out 120vac. Hot button has a dry set of contacts.

https://www.amazon.com/Delay-Timer-Relay-Second-Socket/dp/B08CV58X9Z/ref=sr_1_3?crid=2HAT31LMBNT9T&dib=eyJ2IjoiMSJ9.2tJBCD4WeaYM5yY9BIiDrzx1lcNGL-jEL4gD4Ilkr23ny4kPrphlWhtpF_vkcSH6oVEtOhtNCoYhQsRL2SBIBxC6EldD6p1rF0801Z58NvStYtQdVqvgnQkYojSy9zuf2-8aT_z1r1ddgr0Dmshn8v4Wd4DqFcMiFgj90ZfswI1kZTEkSkPzzrvr6weZoGmTG1FGKbtn_61xix-E-IPsdFxwHH7PyHmAOVW_IY1C3qY._AxJ20B9XxCcpyUleqo3TACQD5KBM0cgO_FZK3GLQtk&dib_tag=se&keywords=120vac+time+delay+relay&qid=1770411998&sprefix=120vac+time+delay+relay+%2Caps%2C1016&sr=8-3

 

[jahmes143]

Thanks guys. I spoke with "our low-voltage guy" and his initial thought was a motion senser that has an internal relay output (dry contact, volt-free, isolated contact). I don't know what any of that means but thought I'd pass it along. He's researching a bit more and I will let you know what he comes up with.

 

[Fitter30]

Could use Alexa with a relay.

 

[Bannerman]

Could use Alexa with a relay.

Linked below is one example of a WIFI controlled relay, equipped with a momentary dry contact. This could be connected directly to the Hot Button contacts in the WH, activated remotely through WFI by Alexa, Google Home or standalone motion sensor(s) which transmit a WIFI signal.

Smart WiFi Wireless Relay Switch Module,

 

[jahmes143]

Bannerman - Thanks for the link. We will pass that option along to the low-voltage specialist. Ideally, we are trying to keep everything hardwired, no wi-fi. KISS.