Adding Remote Switch to HRV (LifeBreath RNC-155)

[organometallics]

Hey all,

I was thinking of adding an on/off switch to remotely turn on my HRV based on the house conditions.

First, a little bit about my HRV it does NOT have a central HRV controller. It is controlled in 2 ways:

1. The thermostat: fixed schedule, runs on high-speed 20 minutes every 1 hrs
2. Bathroom timer switches (4 of them): runs on high-speed for 20, 40 or 60 minutes based on how long this was pressed

The above works in parallel, so if the for example the thermostat turns on the HRV at 9:00 am and turns it off at 9:20 am, but if a bathroom switch turns on at 9:05 am for 20 minutes also, the HRV will run for a total time from 9:00 am to 9:25 am.

So, I want to add a 3rd way to turn on my HRV using one of these switch/relays (I don't know the difference), like a Shelly Plus 1 UL:

https://www.shelly.cloud/en-us/products/product-overview/shelly-plus-1-ul

It is UL listed and dry contact. I believe it needs its own power, so I'm not exactly sure how to add it directly to the HRV rails on the photo attached here.



Anybody try this? thanks

[organometallics]

Actually, maybe a better question would be, what each terminal means on the HRV terminal block.

The installer manual does not seem to have this information, just tells you what to connect to via numbers for each controller example.

thanks

[Admin]

If you wire the block this way it will allow a dry contact to run the high speed.

I would eliminate the white jumper, so it doesn't interfere with the other control options and see if that works first.

[organometallics]

Hey, thanks for that!

Do you know if the terminal block is providing DC or AC power? On another forum someone mentioned that I might need to add a "rectifier" to the switch so that it converts AC to DC....but to be honest, I have no idea if this required as the switch can support both AC and DC.

[organometallics]

I ended up finishing this project by connecting the Shelly Plus 1 UL to the same high-speed settings as my other HVAC controls.

Now I set it up the it automatically turns on the HRV for 1 hr if CO2, radon, and humidity levels (in the bathrooms only) are elevated due to showering/bathing.



This add a whole new level of smartness to ventilation in my home.

The Shelly has its own dedicated power supply of 12 VDC.