Wiring 115v MiniSplit Cutoff Box

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  #1  
Old 07-11-18, 07:16 PM
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Wiring 115v MiniSplit Cutoff Box

Read this thread, but wasn't entirely sure on some of it:
https://www.doityourself.com/forum/e...nnect-box.html

How should I be wiring up the 20 or 30 amp breaker in the circuit box?

In my haste, I connected the 115v split to a 240v cutoff - I had it connected to a 2-slot 30amp breaker inside. Ended up getting on autopilot and completely neglected the fact that my unit is 115v. The unit powered on but the breaker tripped immediately. Checked, thought it was a loose ground, re-secured, turned back on, stayed on for about 15 minutes but then shut off again. Heard a pop from the outdoor unit as well when the breaker tripped. That's about when I realized I had wired in 240v. Feel like I blew the main board or compressor - its fan never turned on. I'm confident I got the requisite amount of refrigerant in - pulled a vacuum and it held for 30 minutes before I released the precharged refrigerant from the compressor into the lineset... attempted to power it up, and the rest is history.

Bit of a costly, stupid mistake. Anybody have any thoughts or recommendations?
 
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Old 07-11-18, 10:57 PM
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Welcome to the forum.

Per the directive of the DIY administrators.... we do not discuss charging methods or pressures.

If I was troubleshooting your unit I would have a service manual and a meter to check power supply voltages. From here we would just be guessing. You could have fried the control board, the compressor or the 24v supply transformer.

Your title is asking about wiring a disconnect..... what is it you have a question about ?
 
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Old 07-12-18, 10:22 AM
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Got it - I'll refrain from doing so in the future.

My question with respect to wiring the disconnect - how do you set up the breaker in the circuit box? When I set it up for 240v I had that 2-slot 30amp breaker. Would I just downsize to a 1-slot 30amp or 20amp breaker? Then cap the neutral in the circuit box, or put it on the grounding bar? Then inside the disconnect I was assuming I'd have the neutral from the compressor wire-nutted together with the neutral from the circuit box. Hot from circuit to line, live from compressor to load... does that sound about right?
 
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Old 07-12-18, 10:34 AM
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At the main panel you'd replace the two pole breaker with a single pole breaker of the correct amperage. You could put a second single pole breaker in as a spare/filler or use a snap in panel blank. The black wire connects to the breaker and the white wire connects to the neutral bar.

Since you most likely have a 240v disconnect..... there is no neutral bar in it. The black wire will go to disconnect. The white wire will need to be wire nutted to the white wire from the condenser.
 
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Old 07-12-18, 10:39 AM
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Hi, what does the mfg. recommend for wire size and over current protection? Use that size breaker in your panel, connect the black from the cable to the breaker terminal, connect the white to the neutral bar, and connect the ground to the ground bar in the panel, at the disconnect connect the black to the line side and the white will splice onto the white from the compressor , blac from compressor to load side of disconnect, connect ground from compressor along with the ground from the panel and using a suitable lug connect it to the side of disconnect switch.
Geo
 
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Old 07-13-18, 12:18 PM
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Awesome... ok. So the indoor unit is working fine, now the compressor is just not coming on. I'm going out of town for an extended duration tomorrow, but going to see if I can work on some things later today.

Thank you guys so much for all the input you've given.
 
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