The incoming power to this unit is measuring 210 volts, which is about what you're going to see in a typical 208 power supply. This is eric with hvac school, and i just want to do a quick video today on something to look out for if you have a residential system that could be installed in a commercial space, your incoming power voltage will typically be 208 instead of the normal 240 Volts and what you can see a lot of times is the transformer is factor set for 240 and it was never changed so this can cause some nuisance calls. Typically, they run fine, but it's it's still good to correct this issue. When you see it, you can definitely run into problems more if the control wiring is longer and or undersized, and you know, depending on just the voltage drop of how big the site is as well, because you might not be getting 208 to your unit, you might Be getting on the lower end of that and then in the afternoon the power can drop even lower and then you'll get that nuisance.

Call that ac is not working at five in the afternoon. Just something to definitely look out for we're we're pretty close on this. But it's going to be low, it would normally be like 25 or 26 volts if the transformers tapped properly so we're gon na shut this system off and take a quick look in the air handler and show how to change that tap. It's mandatory to lose at least one screw each time you take a panel off remember that tip yeah.

We're gon na pull this transformer out in this case, because we can't really see the the name plate on it like, as far as to show it good. In a camera angle, normally in the field, you wouldn't have to do this because you could use a mirror. Your phone, some other means get on a ladder and you'd be able to actually see what we're about to show you now, the painful b-roll of me struggling to pull a transformer out with the wrong tool. So now we have a better view for the transformer.

The common we're going to leave alone and we're going to move this tap from where it says, 240 to 208 to match our incoming voltage. So now i've switched the wiring from 240 to 208 and i've left common, where it is so now we can start our system back up and test our result, we're showing 26 volts. Now, instead of the 23, which we don't see as big of a difference on this trainer, because the wiring is so short in between, but once you add in longer wires, undersized wires or lower than expected high voltage, you can see enough of a drop to have A contactor intermittently not pull in and cause issues with cooling and that's how to re-tap a transformer for 208 volt power supply thanks for watching our video. If you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school is far more than a youtube channel.

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