Please help me with a sensor on my Carrier GT-PX (Climatemaster Tranquiity 27).  I have a 3 ton packaged unit working perfect for 3 weeks now, and a 2-ton split that was just connected to the refrigerant lines and attic air handler.  I'm ready to startup the split but need to figure this out.  I believe the sensor is the FP2 thermistor but could be wrong. 

It is a purple wired sensor zip-tied in the unit clearly there to be connected afterwards - but there is nothing about it in the unit or CXM board manuals.  It comes with a clip to attach it to a pipe, and based on the clip its for a 3/8" pipe like the liquid refrigerant line. Then it has two bare ends that look like they are suppose to push into a molex wire harness.  I don't want to begin startup without having this in place.

The FP2 locations on the molex connector on the CXM board are just jumped together with a purple wire.
So do I remove this jump, insert the thermistor connectors, and clip the sensor somewhere? 

Please help confirm where I insert the wire leads and what pipe and where do I clip the sensor onto.  Thanks. 

climatemaster.com/downloads/97B0047N01.pdf Page 18 may help you.

Regards,

Masoud

Page 18 of the manual has nothing on where the FP2 sensor goes in the unit although it does show a sensor bulb attached to the suction line at the air handler but no description if its the FP2 or where its connected. Plus the suction line is a very standard 3/4" and this sensor came with clips for liquid line sizes.

It goes on the suction header on the evap coil in the air handler. It is a safety for coil freeze up (dirty air filter, low air flow). Splice it into the purple wires on the molex connector.

OK, I luckily found this described on a chart inside the flip down cover that goes over the CXM board.  I had extra literature stored on top if it.  But I am a little puzzled why they couldn't include this diagram in the manual. 

So it says I clip the violet wire that is jumping the 2 FP2 spots on the molex harness, then splice into that with a wire leading to the fan coil, and to place the sensor "on copper tube between distributor and expansion valve".  Oddly the included pipe clips for the sensor are for smaller liquid lines but I'm hearing its the suction line. 

Well I'll hook up now and run through the start-up sequence as everything else is ready. 

And by the way, my Carrier dealer had no idea of where it went.