Water Supply Switching


#1

Hello all, new to Rachio.

I’m interested in purchasing a Rachio 3, but I wanted to see if my proposed setup would be viable.

I would like to use two different water supplies, rain barrel system and city water. I want to place a float switch in the barrels that operates two motorized ball valves. Rain barrel, normally open, and city water, normally closed. If the float swith detects low water it closes the barrel line and opens the city water line. I wanted to check if I could wire and power all three using one of the sensor ports on the Rachio. The ball valves are 24vac.

If that’s not a possibility, could I use wired flow meter to accomplish the same?

Thanks in advance.


#2

@jpmckane - electrically speaking the Rachio Gen 3 has a dedicated AC +/neutral (-) ports. The question will be the current the two ball valves use when activated. Do the ball valves need full time current to remain open? Or just a momentary pulse to move? Instead of the dedicated AC ports, the Master valve might be the best port to use. Additionally, one might need to have a pump start relay as I’m assuming there will need to be a pump to pressurize the water out of the rain barrel.

The bigger issue is the plumbing code as far as cross-connecting a potentially contaminated water source (rain barrel) with the city water. This may not be permitted and at the least there should at least be a double check backflow prevention device so the rain water/irrigation system won’t back flow into the city water supply.


#3

@Dlane thanks for the reply. The ball valves will only need current when the state changes. I haven’t decided on the specific unit’s yet. Do you know the current the dedicated AC ports can handle? Curious what the benefit of using the master valve would be, please school me :slight_smile:

My plan was to use an on-demand pump so I wouldn’t have to go down the relay route. Either an AC version plugged into an outside receptacle or a small 12VDC pump that I could power with a solar cell.

I agree with the concerns on connecting the two types of water sources. If code permits, my design will absolutely include a back flow prevention system.


#4

@jpmckane - the Master valve is only energized when the Rachio is calling for water for a zone. That way if there is a pipe break between the master valve and the zone valve or the zone valve doesn’t completely shut off, the master valve will prevent/reduce wasted water and damage.

The dedicated AC ports will have voltage present all the time.

The Rachio power supply is I believe a 1,000 milliamp power supply. If the power supply has a “brown out” due to too much current pull then the Rachio will throw an alert.

Another design option would be to have the city water come into the rain barrel - with an air gap. So a low water sensor would open a valve to the city water and a high water sensor would turn off the city water. The two sensors could be in a tight range to prevent too much city water from being put into the rain barrel. And if the city water input rate was equal to the maximum flow from all the zone’s it shouldn’t run dry.

Edit: After thinking about it overnight the simplest solution would be to come out of the master valve and through a float switch that is normally open when the water is high (so closed when low) and feed a sprinkler zone type valve on the city water supply to fill the tank. I might also use a pump start relay also on the master valve, or a master valve after the pump, to prevent the tank from running dry due to a leak and ruining the pump by running it dry.