Trying to clean up another contractors mess. New Trane system they installed this past winter, so this is the first summer with it, model numbers: TAM7A0C60H515BA;4TWR5061E1000BA.
The air handler is their new style with an electronic TXV. It has a honeywell zoned system with 4 zones and a bypass damper. We originally were called in to fix some disconnected/unsealed ductwork, which we did (connected a return that never was and mastic'd some duct connections).
Now that summer is upon us (NE Florida) we have a fun new issue. The customer was complaining that the c/u rapidly cycles on and off.
After looking at how the zones were configured the smallest zones had (4) 8" drops being fed off of them, which automatically sent up the airflow concern. We were able to duplicate the LPS shut down by running it with just one zone calling (static pressure readings were through the roof of course). We tied the two smallest zones together (wired the dampers together to act as one, essentially eliminating a zone altogether) to test this theory. We also told the homeowner to let us know if it did happen again and if it did what zones were calling at the time. Well we heard from the homeowner today who said that is has been happening and more frequently and it wasn't biased as to how many of the zones were calling, he in fact noticed it even when all of them were.
We have obviously tested and made sure the dampers were opening and closing, actually temperature wise the whole house is at the temperature the thermostats are asking for.
Not being a Trane dealer, my question would be is there something with the electronic txv that can or needs to be adjusted? Am I missing something? I'm not sure what to do next at this point. I don't want to condemn the whole duct system if I'm missing something else to check out first.
I'll provide some supplemental information that may help. The unit as far as we know has never actually frozen over as a result of any of these issues. Like I said it cools just fine. The LAT sensor shut down on the honeywell zone system is set to i believe 32ish degrees (we originally thought it may have been shutting down on the LAT sensor). With all zones calling the static is well within acceptable limits (under .5 total static).
Thanks for any help! And sorry if this is in the wrong forum subsection....