Trane OXBOX J4AH4P Series Installation Instructions Manual page 20

This coil comes with a factory installed piston metering device. See Table 1 for factory installed piston
size. Some system combinations will require a different sized piston to be field installed.
Contact your local parts center to order the appropriate MAYORIACHP piston kit for your system
combination.
Use Table 3 for TXV kit part numbers.
A TXV may be required to achieve minimum efficiency ratings or for long refrigerant line set
applications. Reference AHRI for system combination ratings.
Reference Table 4 to charge the system by superheat when using a piston. Reference the outdoor unit
installation guide to change the system by subcooling when using a TXV.
Table1. Factory installed piston size for each model. Additional piston sizes are provided in the
ship-with literature bag as necessary.
Model
J4AH4P18A1A00AA
J4AH4P24A1B00AA
J4AH4P30A1B00AA
J4AH4P36A1B00AA
J4AH4P42A1C00AA
J4AH4P48A1C00AA
J4AH4P60B1C00AA
* means that this piston is pre-installed
Table 2 . Piston size for system combination
Outdoor Unit Model
J4AC3018A1
J4AC4018A1
J4HP4018A1
J4AC3024A1
J4AC4024A1
J4HP4024A1
J4AC3030A1
J4AC4030A1
J4HP4030A1
J4AC3036A1
J4AC4036A1
J4HP4036A1
50 52 56 58
X*
X*
Indoor Unit Model
J4AH4P18A1A00A
0.050 factory installed
J4AH4P24A1B00A
0.056 factory installed
J4AH4P30A1B00A
0.063 factory installed
J4AH4P36A1B00A
0.073 factory installed
63 65 68 70
X*
X X
18
73 75 76 83
X*
X*
X*
Piston Size(R410a)
0.050
0.050
0.050
0.056
0.056
0.056
0.063
0.063
0.063
0.070
0.073
0.068
90
X*