Question about relay application

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td1236

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Customer has a battery back up system with a smart controller. The smart controller locks out certain non critical loads in the event of a power outage, via control wire and relay. The voltage from this control wire is 24 volts.

The customer would like 2 heat pumps used for his pool to be locked out when the power goes out. The heat pumps are controlled through a control wire that comes from a 5 volt control board to the heat pump.

Is it possible to interrupt heat pump control wire with a relay?
 
Yes it's possible. I've done something like this. On the type of controller I was using (Enphase System Controller) one could just run the 5V directly to its contacts. If you've got relays already installed, you could run the 5V through one. You may have to use Chapter 3 or Class 1 wiring in relay enclosure if there are 120 or 240V loads connected to other relays there.
 
jaggedben said:
Yes it's possible. I've done something like this. On the type of controller I was using (Enphase System Controller) one could just run the 5V directly to its contacts. If you've got relays already installed, you could run the 5V through one. You may have to use Chapter 3 or Class 1 wiring in relay enclosure if there are 120 or 240V loads connected to other relays there.
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What type of relay would you recommend for this application. The relay will be near the heat pumps at pool equipment, so far away from other load shedding relays in the garage.
 
td1236 said:
What type of relay would you recommend for this application. The relay will be near the heat pumps at pool equipment, so far away from other load shedding relays in the garage.
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I think we need more detail.
You want to interrupt 5V?
The backup controller turns on and off a 24V control source, or provides a contact? What is the backup controller model?
 
jaggedben said:
I think we need more detail.
You want to interrupt 5V?
The backup controller turns on and off a 24V control source, or provides a contact? What is the backup controller model?
Click to expand...
It's an IQ system controller through Enphase. Here is a picture of a schematic in normal applications.
 

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That's easy. Either interrupt the 120v line between the 1p breaker and the power supply, or interrupt the +24v output between the power supply and the upper Wago.

Your relay's coil should match the controlling voltage, and the contacts rated for either 120vac or 24vdc. A Relay-in-a-Box is convenient if you have no handy enclosure.
 
I think you probably don't need another relay. You can go to the System controller directly or use the IQ Load Controller relays if available.

Are the IQ load controller relays being used for other loads right now or are they available? Is there only one IQ load controller? Are you Enphase certified to use Installer Toolkit to set up additonal loads? I recommend the last one.

Your 5V heatpump control can be diverted to the System Controller, like a switch leg. There are four auxiliary contacts in the System Controller; an IQ Load Controller will be wired to two of them. So if there's only one Load Controller you would have two more contacts to use in the System Controller. Just need to set them up with the software and connect the heat pump control wire. I'm assuming you know exactly what that control wire controls at the heat pump.
 
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