192
Use this piston chart to ensure you are using the correct size at the indoor coil for 13SEER products.
NOTE: 14SEER and above, manufacture intends for systems to use a TXV.
Aspen R454B Piston Size Chart
For Aspen coils and air handlers using R454B refrigerant, the piston (flow check) size is determined by the coil’s nominal tonnage. The following table shows the standard piston orifice sizes for R454B systems:
| Nominal Tonnage (MBTUH) | Piston Size (inches) |
Notes |
|---|---|---|
| 1.5 ton | 0.052 |
Common for smaller residential coils |
| 2 ton | 0.059 |
Standard for 2-ton R454B coils |
| 2.5 ton | 0.065 |
Typical for mid-sized residential units |
| 3 ton | 0.071 |
Best match for 3-ton R454B systems |
| 3.5 ton | 0.076 |
Matches 3.5-ton coil flow |
| 4 ton | 0.076 |
Some distributors list 0.076 for 4-ton R454B coils |
| 5 ton | 0.077 |
Common for 5-ton residential R454B systems |
Key points:
-
These sizes are for R454B; R410A or R32 systems will have slightly different piston sizes (R410A pistons are generally 3–11% smaller than R22/R454B) PICKHVAC.
-
Aspen’s universal coil nomenclature lists R454B piston as an option for A2L refrigerant detection systems and other R454B/R32 configurations Aspen Manufacturing+1.
-
Piston size is critical for matching coil flow to the compressor and ensuring efficient system operation.
