Data Aire DAPA-05 - 5.9.1 Thermal Expansion Valve; 5.9.2 High Pressure Cutout Switch; 5.9.3 Low Pressure Cutout Switch

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The refrigerant circuit has an adjustable Thermal Expansion Valve (TXV). The TXV is factory adjusted
to their normal rating. Any field adjustment should be to “fine tune” a system that has stabilized and
already has acceptable operating parameters. Adjusting a TXV to produce large swings in superheat
is not recommended.
Proper TXV operation can be determined by measuring superheat. The correct superheat setting is
between 8 to 15°F (4.4 to 5.6°C). If too little refrigerant is being fed to the evaporator, the superheat
will be high; if too much refrigerant is being supplied, the superheat will be low.
To adjust the superheat setting:
1. Remove the adjustment cap from the valve.
2. Turn the adjusting stem counterclockwise to lower the superheat.
3. Turn the adjusting stem clockwise to increase the superheat.
NOTICE: Make no more than one turn of the stem at a time. As long as thirty
minutes (30) may be required for the system to re-stabilize.
High Pressure Cutout Switch
Each refrigerant circuit is protected by a high-pressure cutout switch (non-adjustable) with manual reset
button. The switch is typically located in the evaporator near the compressor. The high-pressure switch
rating is:
Table 21 High Pressure Cutout Switch Setting
Action
R 410
R 407C
Cut-out (Open)
575 PSI
450 PSI
Cut-in (Close)
Manual Reset
Manual Reset
Low Pressure Cutout Switch
Each refrigerant circuit has a low-pressure cutout switch (non-adjustable) which features SPST open-
low switch action and automatic reset. The switch is typically located in the evaporator near the
compressor. The low-pressure switch rating is:
Table 22 Low Pressure Cutout Switch Setting
Action
R 410
R 407C
Cut-out (Open)
50 PSI
30 PSI
Cut-in (Close)
90 PSI
50 PSI