mini split wiring or symptom diagnosis

[inphx]

I have a LG condenser capable of driving 3 heads. It is set up with two heads. In my home I have four sets like this. One condenser/2 head pair seems to work "well" when the pair of heads are ON and you can hear from one head a subtle gurgle in the pipe if only one head is on.

Checking the diagrams is it possible the wires on 3A and 3B are swapped? I can run speaker wire to ohm out end to end but the installer wrapped the copper lines so i cant identify destination and it doesn't make sense to disconnect line sets to confirm what feeds what. So i am inclined to experiment and just swap these two wires.

Any fatal risk in that experiment?

 

[yeldogt]

If it's wired correctly -- what are you trying to achieve?

We can sometimes hear a noise when one unit is off -- remember the units are never really off unless you have them on "off" and that should only occur when the room is unoccupied.

Mine are only off in unoccupied bedroom -- those being completely unused ... like our guest bedroom. They other areas are simply turned up to a higher temp.

 

[inphx]

I am not certain they are wired correctly, they seem to work almost ok when both are on but when one or the other is on alone its poor.

Its new construction so i am only on site weekends and end up turning on all the heads to cool off when i get there. But from recollection - just one head in this pair doe-sent really work.

Digesting the data points now. Its my theory that they are miswired ... plausibly a single head is opening the valve to the alternate head.

 

[bzinsky]

Disconnect all the wires indoor and outdoor unit, connect leads on the inside to a 9 volt battery, test voltage outside

 

[Jackfre]

I suspect that the evaporator wires are crossed, 1-2, 2-1. Should be 1-1, 2-2.

 

[Ohmthis]

I have seen this happen before. A friend of mine installed a multi head mini split and got two of the cables crossed. He couldn't figure out what was happening. One of his heads froze over even though the system has a thermistor to read coil temp and shut off the head if it started to frost. He was certain that he had a restriction somewhere. After looking it over and putting some thought into
It. I Ohmed the cables and found the head that froze was crossed to another head. Swapped them and voila, it was magic again.

 

[chrispyny]

Purchase a tone generator for telephone lines. Clip tone sender to one wire, and use wand to confirm appropriate wire at other end. Rinse, repeat.

Tone kits are $30 online.

 

[LS6 Tommy]

X2 on the swapped wires as stated by Jackfre.

Interesting "Nuclear Options" on wire tracing, guys. Disconnecting both ends of the wires, twisting one pair together at a time and ringing them out with a VOM set to continuity has worked fine for me for over 30 years...

Tommy

 

[inphx]

Thanks guys - the 3 wires from each head have same color codes when terminated at condenser. 2 of the 3 are power, so these obviously work.

The problem with ohming out wires is i cannot ohm out the line set to confirm wires match the line set.

I did a careful test, turned on the opposite head and touched the accessible lines on the opposite unit. Ice cold. Waited about 2 minutes and only turned on the head at the accessible head - no cold lines.

The two control wires, same color, are adjacent on the condenser terminal strip and i will swap them this afternoon. (3A and 3B)

 

[inphx]

Success!

 

[yeldogt]

Glad it worked out -- I'm always afraid to play with circuit wires unless I'm sure I have the correct ones.

I guess installer did not use the typical mini wire -- it's color coded?

 

[Ohmthis]

Good deal! Glad it worked out for you.