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MSEV Series and USHX Hardware Installation Manual Rev 1.7
2
Mechanical Installation
This section describes the mechanical installation of a MSEV series valve and USHX. Figure 2-1 below
shows an example of a typical system where the MSEV series valve and USHX devices would be integrated
into. Like conventional thermostatic expansion valves (TXVs) or electronic expansion valves (EEVs), the
MSEV series valve is installed at the inlet of the evaporator. The USHC, which drives and controls the MSEV
series valve, is installed at the outlet of the evaporator, in place of the TXV bulb or EEV controller sensing
device. The MSEV series and USHC are connected together by a wiring harness. A thermistor at the outlet
of the evaporator measures the temperature, and the USHC is powered by the Class 2 power source.
Do NOT turn the power source ON until installation of MSEV series valve, USHX and
wiring harness is complete. For the user’s own safety, only Class 2 power source
should be used to power the MSEV series and USHX devices.
Figure 2-1 MSEV series valve and USHC installation schematic
2.1
Installing a MSEV Series Valve
To install the MSEV series valve, complete the following steps:
1.
Pump down and recover any residual refrigerant from the system.
2.
Remove the current TXV and its bulb or EEV and its controller by cutting. Take care to minimize
the risk of introducing contaminates into the system when removing the existing valve.
3.
Before continuing, clean the copper connections of the MSEV series valve. The OD of the MSEV,
HC-MSEV and VHC-MSEV copper tubes are 3/8”, 5/8” and 3/4” respectively.
Do NOT reduce the length of the copper tubes when brazing.
Flare fittings should be used if the copper tubes length is reduced.
4.
Position the valve as displayed in Figure 2-2 and ensure the arrow mark aligns with the direction
of fluid flow. The blue arrows show which way fluid is supposed to flow through the valve. Also
ensure that the MSEV series valve is installed in an upwards orientation or at any angle less than
90° in either direction (represented by the curved green arrows).
