Two HVAC technicians explain how an ABC control board wires valve actuators, with the R terminal connecting to the ACC contact and the C terminal to the valve coil. An end-switch on the W/Y terminals prevents the compressor from starting until the valve fully opens. They confirm two geothermal loops can run off one unit if properly designed, and suspect a power surge damaged the board.
If you turn it on and air hits it, boom. It's on the board, it's on the ABC board. Yeah, R on the ABC board goes to the ACC com. The C on the ABC board goes to your valve, and the ACC normally open goes on your— goes to your valve.
So I go from my R on the ABC board down to my ACC. And then I'll come out of my normally open, back out of my valve. Yeah, and that's what I was thinking, but then I got to look at the valve.
But all it's doing is the ABC ports just breaking you hot.
Yeah, but I was looking at that and it was getting me confused because it's showing my yellow and everything else coming from the thermostat.
Wait a minute, you know, you're gonna do—
you're gonna connect to your WY and you see Yeah, do I need the jumper between the two?
No, that's an end switch. You don't have it, you don't have nothing to sense the end switch, so all you're going to do is connect on your W/Y and see.
Got it, that makes sense. So don't follow this, I'm just basically following this one. Yeah, I got that part of it. But I was thinking we was on that one for a slow opening.
No, I mean, you wire them the same with slow open. The only difference here is this end switch.
Okay.
It's got an end switch, which is basically an input to tell, um, okay, so what this end switch does is it doesn't allow the compressor to come on until it reaches fully open.
Okay.
But it'll be fine. It'll get there quick enough.
Now, once doing this water pressure, since we're running 2 geos off one unit, do I have to worry about pressure drop on any of this?
No, I've already— I mean, they've already got all that figured out. They should have that wired properly.
I told them how to work the well.
Yeah, everything should be good there. What happened? Surge come through and popped all of it? I don't know, that one's been acting like it's going to give up any minute anyway.
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