Recommendation 3 — Use when:
•system return water is less than 135° F for prolonged periods of time
•system flow does impact flow through the boiler(ie. zoning, mixing)
•requires addition of RTC Return Temperature Control and accessories
Pipe Sizing and Notes
| SUPPLY |
| RETURN PIPING SIZE (IN) | ||||
|
|
|
|
| |||
| PIPING |
|
| RETURN | RETURN | ||
| SIZE (IN) |
|
| HEADER | BRANCH | ||
|
| (1) | RETURN (2) | (2A) | (QTY.) SIZE (2B) | ||
| 20°F |
| 40°F | 20°F | 40°F | 20°F | 20°F |
MODEL | DROP | DROP | DROP | DROP | DROP | DROP | |
| 2 |
| 2 | — | — | ||
| 2 |
| 2 | — | — | ||
| 2 |
| 2 | — | — | ||
|
| — | — | ||||
|
| 2 | 2 | — | — | ||
|
| 2 | 2 | — | — | ||
| 3 |
| 2 | 3 | 2 | — | — |
| 3 |
| 3 | — | — | ||
| 3 |
| 3 | — | — | ||
| 4 |
| 4 | 3 | (2) 3 | ||
NOTES:
1.All piping is schedule 40.
2.Pipe sizes listed are based on a 20°F or 40°F differential (temperature drop).
Select one to match application.
3.When specified return piping size is less than 3”, install 3” X 12” nipple and appropriate size bell reducer directly into boiler return tapping as shown.
4.Drain valve — ball valve preferable, gate valve acceptable alternative (supplied by others).
- Minimum valve size per ASME code is 3/4” NPT
5.Maximum linear feet of pipe from
6.Minimum linear feet of pipe from point of mixing (where bypass meets return line) to sensor location = 4 feet.
7.Install special 3” x 12” nipple with 1/4” NPT side tapping closest to boiler. Where applicable, use bell reducer to adapt to recommended return pipe size.
8.Proper boiler circulator sizing is listed in Appendix B.
Figure 33: Series 24 Minimum Piping Recommendation 3 - Water Boiler
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