Adjustable TXV

[Slugger]

I apologize for asking such a dumb question, but why would a manufacturer install a non-adjustable TXV on a brand new DX unit? There are hundreds of articles on superheat and how important it is to keep a system "Balanced". An HVAC system is no question going to lose efficiency over time for various reasons, but if your superheat is off the charts, isn't the best place to start making adjustments at the TXV? If you can't drop your superheat, then doesn't that signal to start looking in other places? Thanks for your input!

[Brian_UK]

The first law of refrigeration is - "Do not play with the TXV."

Unless the TXV has gone faulty there is no reason to adjust the settings of the valve.

There will be far more causes for poor performance such as airflow which should be checked first of all.

[vadivelan]

Non adjustable TXVs are used for standard applications were the load change is very minimal (airconditioners etc.,). For other applications it might be good idea to select adjustable TXVs. Even these are to be rarely adjusted in the field.