Thermal Expansion Valve is a type of metering device which is one of the separation points between the high and low pressure sides of an air conditioning system (the other being the compressor). It depressurises the liquid refrigerant which passes through it, ensuring that low pressure liquid refrigerant is passed on to the evaporator.
The EPR valve should work reguardless of if the TXV is in the air stream. The TXV in the airflow shouldn't make it act any different since it is sensing the temperature at the bulb instead of at the valve it's self.
Temperature is not a pressure or force acting on a TXV (Thermostatic Expansion Valve) diaphragm. The TXV diaphragm is primarily influenced by refrigerant pressure and spring force to regulate the flow of refrigerant into the evaporator coil. Temperature affects the superheat setting of a TXV but is not a direct force acting on the diaphragm.
Liquid cross charge in a thermostatic expansion valve (TXV) occurs when the refrigerant flowing through the valve is at a temperature below the designed setpoint. This can affect the valve's ability to maintain proper superheat and refrigerant flow, impacting the system's performance and efficiency. Adjusting the valve setpoint or system charge may be necessary to correct the issue.
Three factors that determine the capacity of a TXV are superheat setting, pressure drop across the valve, and the flow rate of refrigerant passing through the valve. These factors work together to ensure that the TXV maintains proper refrigerant flow to achieve efficient system operation.
typical prices are from $725-$1500 for thermostatic expansion valve replacement
A dx or direct expansion coil describes a type of heat exchanger. (As compared to chilled water.) The tx valve regulates the refrigerant. Systems without a txv will have a fixed orifice. The txv is generally more efficient than a fixed orifice.
The Txv usaully will not let any flow though valve causing low side to pump down or go off on low pressure. Because it is the charge that opens the diaphragm/valve against the spring pressuse (keeps the valve closed) of the TXV, an absense of the charge will allow the spring pressure to keep the valve closed; consequently starving the evaporator coil of a saturated vapor, until the system pulls down into a vacuum. If the system is equiped with a low side pressure switch, the system should go off on low pressure.
If it's a TXV system, it'll be located between the receiver-drier and the evaporator.
It could be restriction or low charge. Meaning you could have a bad txv valve or not enough refrigerant in the system.
Difference between txv and exv.
Thermostatic Expansion Valve (TXV, TEV). Any high efficient system requires one.
Are you sure it has a fixed orifice tube system? Most heavy duty trucks use a Thermal Expansion Valve (TXV) system. In both systems, the metering device (orifice tube or TXV) is located between the condenser outlet and the evaporator inlet.