I've got one single 12000 btu ac unit and one
Taking apart the hand held remote won't serve any real purpose as none of the parts inside are replaceable. Since you have 3 different units, with 3 different hand held remote. I'm wondering, if perhaps, you're using the wrong remote on that one unit. As each one has a different remote code.
In addition, I have learned from experience, that if the display screen on the hand held works, the problem is not in the hand held. Now, that's not to say, Operator Error can't play a role in it. But, most times, it's the receiver in the unit,that may be causing the problem. Or the hand held is to far away or something is blocking the signal in between.
Almost every appliance we sell, has a radio frequency remote control. The most problems we incur is with weak or dead batteries or operator error. The problem with batteries is that you don't now how long they sat in a warehouse, before making to a retail outlet and then how long they sat on the shelves there, before they were sold. They may have enough power to activate the handheld remote, but not enough to transmit a strong signal. So, check the strength of the new batteries you installed.
Hope this helps and thanks for choosing FixYa.
on Jul 02, 2017