Armstrong S Series Circulator Pumps Buyers Guide & Review
The Armstrong S series of in-line circulator pumps is suitable for domestic hot water systems. This series is built using a standard three-piece design that features a radially-split body, oversized shaft, centrifugal impeller, positive mechanical seal, and modular construction. The S series has been used by HVAC professionals for decades because it is cost-effective, durable, and easy to maintain.
Features
- Maintenance free design which has permanently lubricated ball bearings and requires no maintenance at all
- Radially-split body can be left in-line while servicing pump, eliminating disconnecting of pipes
- Oversized shaft made from stainless steel
- Balanced centrifugal impeller ensures maximum water delivery in the HVAC system
- Proven seal design made from strong and long-lasting materials for extended operating life
- Three piece modular construction and back pull-out design for easy replacement of wear components
- Certified ≤ 0.25 weighted average percent lead and complies with California Health and Safety Code Section 116875 (commonly known as ab1953)
| ARMSTRONG S SERIES CIRCULATOR PUMPS |

Armstrong S Series Circulator Pumps
Model Comparison Chart
| Model |
Flanges (NPT) |
HP |
Voltage |
Material of Construction |
GPM |
Max. Head |
| S-25 |
Sold separately |
1/12 |
115 |
Bronze |
31 |
6' |
| S-35 |
2" |
1/6 |
115 |
Cast Iron |
72 |
11' |
| S-45 |
Sold separately |
1/4 |
115 |
Bronze |
109 |
16' |
| S-46 |
3" |
1/3 |
115 |
Cast Iron |
112 |
19' |
| S-55-3 |
3" |
1/2 |
208-230/460 |
Cast Iron |
121 |
24' |
| S-35 |
2" |
1/6 |
115 |
Bronze |
72 |
11' |
| S-46 |
3" |
1/3 |
115 |
Cast Iron |
112 |
19' |
| S-55-1 |
3" |
1/2 |
115/230 |
Cast Iron |
121 |
24' |
| S-55-3 |
3" |
1/2 |
208-230/460 |
Cast Iron |
121 |
24' |
| S-57-3 |
3" |
3/4 |
208-230/460 |
Cast Iron |
139 |
29' |
| S-57-3 |
3" |
3/4 |
208-230/460 |
Cast Iron |
139 |
29' |
| S-57-1 |
3" |
3/4 |
115/230 |
Cast Iron |
139 |
29' |
| S-45 |
Sold separately |
1/4 |
115 |
Bronze |
109 |
16' |
| S-55-3 |
3" |
1/2 |
208-230/460 |
Bronze |
121 |
24' |
| S-55-1 |
3" |
1/2 |
115/230 |
Bronze |
121 |
24' |
| S-69-1 |
3" |
1 |
115/230 |
Cast Iron |
160 |
34' |
| S-69-3 |
3" |
1 |
208-230/460 |
Cast Iron |
160 |
34' |
| S-57-3 |
3" |
3/4 |
208-230/460 |
Bronze |
139 |
29' |
| S-57-3 |
3" |
3/4 |
208-230/460 |
Bronze |
139 |
29' |
| S-57-1 |
3" |
3/4 |
115/230 |
Bronze |
139 |
29' |
| S-55-1 |
3" |
1/2 |
115/230 |
Bronze |
121 |
24' |
| S-55-3 |
3" |
1/2 |
208-230/460 |
Bronze |
121 |
24' |
| S-46 |
3" |
1/3 |
115 |
Bronze |
112 |
19' |
| S-57-1 |
3" |
3/4 |
115/230 |
Bronze |
139 |
29' |
| S-69-3 |
3" |
Bronze |
1 |
208-230/460 |
160 |
34' |
| S-69-1 |
3" |
1 |
115/230 |
Bronze |
160 |
34' |



| MATERIALS OF CONSTRUCTION |


*For a complete part listing, please refer to the repair parts manual*
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