Splice longer wire onto Mitsubishi FH minisplit thermistor
Hi all,
I ordered a PAC-SE41TS-E for my minisplit to allow it to sense the temperature in the living room with the unit located in the hallway. It is just a thermistor in a plastic case with a long wire. Mitsubishi documentation lists it as compatible with the FH minisplit. However, when it arrived, it did not have the correct connector for “plug and play” installation. The instructions (located here: http://meus1.mylinkdrive.com/files/PAC-SE41TS-E_Tech_Data_and_Install_Manual.pdf) are rather vague. My plan is to simply cut the connector off the wire leading to the existing thermistor and splice it onto this new one.
Here is the question: Assuming the longer wire doesn’t provide enough resistance to affect the thermistor operation, since the wire is provided by Mitsubishi, is there any way I can mess up the splice that would cause enough resistance to alter the temperature reading? I was just going to use a crimp connector.
Thanks in advance!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Those are typically 10k NTCs. At room temperature even if you have a couple hundred feet of 20 gauge wire, you are only adding a couple of ohms of extra resistance, not enough to worry about. Solid crimp is all you need for a good connection.
Thanks Akos, electrical is not my strongest suit, so I just wanted to make sure before I start snipping.
What type of connector are you going to use?
There is nothing better than a good soldered connection under heat shrink tubing.
I have not tried this new connector no skill water proof solder connector. You will need a heat gun to install them. They look interesting.
https://www.ebay.com/itm/100-250-300PCS-Solder-Sleeve-Heat-Shrink-Butt-Waterproof-Connector-Wire-Splice/392550102597?hash=item5b65cf3645:m:m4HHRPKn66OT4M3A-s57FbA
Walta
They actually work quite well, assuming they are good quality.
I doubt you’ll have any problems extending the sensor. Use twisted pair wire (better noise immunity), and solid conductors. Anything 24 to 20 gauge is probably fine, larger gauge (smaller number) is better for longer distances.
Don’t try making a soldered connection unless you have the experience to do it correctly. Crimp connections are actually more reliable over time than soldered connections when done properly (there are mil spec documents about this). I would recommend getting some of the Scotch brand UY or UR splices and use those. These splices are common in the telecom industry and have water proofing gel inside. You can install them with pliers and no special tool, and they are available on amazon (be sure you don’t get knockoffs, the real ones are made by 3M). It is very easy to get a proper splice using these with no special skill.
Stay away from the “B type splices”. These are white oval tubes with a metal sleeve inside. The joke in the telecom industry is “what does the “B” stand for? It stands for BAD, because it is a bad splice!”
Bill