Values are for 4f/s flow of water
| Pipe Type | Max. GPM | Max. BTU/h @ 15°F ΔT | Max. BTU/h @ 20°F ΔT | Max. BTU/h @ 25°F ΔT | Max. BTU/h @ 30°F ΔT |
| 1/2" M Copper | 3.2 | 24,000 | 32,000 | 40,000 | 48,000 |
| 3/4" M Copper | 6.5 | 48,750 | 65,000 | 81,250 | 97,500 |
| 1" M Copper | 10.9 | 81,750 | 109,000 | 136,250 | 163,500 |
| 1-1/4" M Copper | 16.3 | 122,250 | 163,000 | 203,750 | 244,500 |
| 1-1/2" M Copper | 22.9 | 171,500 | 229,000 | 286,250 | 343,500 |
| 2" M Copper | 39.6 | 297,000 | 396,000 | 495,000 | 594,000 |
| 2-1/2" M Copper | 61.1 | 458,250 | 611,000 | 763,750 | 916,500 |
| 3" M Copper | 87.1 | 653,250 | 871,000 | 1088,750 | 1,306,500 |
| 4" M Copper | 159 | 1,192,500 | 1,590,000 | 1,987,500 | 2,385,000 |
| | | | | |
| 3/8" PEX | 1.3 | 9,750 | 13,000 | 16,250 | 19,500 |
| 1/2" PEX | 2.3 | 17,250 | 23,000 | 28,750 | 34.,00 |
| 5/8" PEX | 3.3 | 24,750 | 33,000 | 41,250 | 49,500 |
| 3/4" PEX | 4.6 | 34,500 | 46,000 | 57,500 | 69,000 |
| 1" PEX | 7.5 | 56,250 | 75,000 | 93,750 | 112,500 |
| 1-1/4" PEX | 11.2 | 84,000 | 112,000 | 140,000 | 168,000 |
| 1-1/2" PEX | 15.6 | 117,000 | 156,000 | 195,000 | 234,000 |
| 2" PEX | 26.8 | 201,000 | 268,000 | 335,000 | 402,000 |