Could someone help me explain the difference between none-bleeding expansion valve and bleeding expansion valve and how are they connected differently?
A none bleed expansion valve is a valve that will close completely, not to allowing the systems pressures to equalize. This helps prevent flooding the evaporator on the off cycle.
A bleeding expansion valve does allow pressure equalization on the off cycle, were evaporator flooding is not a problem, and allows for a lower torque compressor for starting.
Both valves would be connected the same. Only the internal parts are differant.
These designs are for differant system applications. Changing valves on a system could cause the compressor to slug liquid, or a compressor starting problem.
Why do you ask?
I often got asked and don't know
Some non bleed applicatins will use the TXV as a solenoid because it will provide 100% shut off and in place of using a large solenoid, You can use a small one on the externally equalizer line to act as a pilot duty solenoid and slam the valve shut.
A non-bleed valve will do as the others say; i.e. not allow system equalization to prevent floodback to the compressor upon system startup.
It is also thought that a system that does not equalize after shutdown will spend less time coming back into its nominal operating parameters after it restarts. IOW the compressor isn't spending a lot of time pulling the evap back down to design saturated vapor temp/pressure since the pressure in the evap at startup is more or less already there.
Non-bleed TXV's will require a start cap and potential relay on a single phase compressor.
- Electricity makes refrigeration happen.
- Refrigeration makes the HVAC psychrometric process happen.
- HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.
A building is NOT beautiful unless it is also comfortable.