Circulator Pump Cross Reference: Grundfos, Taco, Bell & Gossett, Armstrong, Wilo
Wet-rotor circulators are the most cross-shopped product in hydronics — five manufacturers make functionally interchangeable pumps for the same zone, and the replacement decision usually comes down to what’s on the truck. This cross-reference runs Grundfos UP/UPS/ALPHA, Taco 00 series, Bell & Gossett, Armstrong, and Wilo against each other, three-speed and fixed-speed classes both, with the columns that decide fit.
Two of those columns do most of the work. Port-to-port length and flange class: circulators mount between existing flanges, so a hydraulic equivalent that’s a half-inch longer, or that takes a different flange bolt pattern, isn’t a field replacement — the tables keep both dimensions beside every cross. Head/flow class: the interchange matches performance classes (a 15-58 class pump to its peers), not exact curves; on a zone sized near the pump’s limit, check the curve before substituting, because “equivalent class” spans real differences at the ends of the curve.
The discontinued-model section matters as much as the brand cross: several legacy Grundfos and B&G models that no longer appear in any current chart have designated modern replacements, and we’ve carried those rows into the tables with their sources rather than leaving them to guesswork.
We stock the common classes across brands and can cross from a photo of the old pump’s nameplate and flanges — send it over for a same-day match.
Table of Contents
- → 1. Hydronic Circulator Replacement Rules
- → 2. Three-Speed Wet-Rotor Circulator Cross Reference
- → 3. Single-Speed & High-Head Circulator Cross Reference
- → 4. Discontinued / Legacy Circulator Replacement Guide
- → 5. Source Reference Documents & Resources
- → 6. Source Your Circulator Pumps From TCI Supply
1. Hydronic Circulator Replacement Rules
Replacing a hydronic inline circulator requires verifying both physical mounting dimensions and hydraulic performance. When swapping between manufacturers, ensure the replacement matches the flange bolt orientation (2-bolt vs. 4-bolt or rotated flanges), casing material (cast iron for closed hydronic loops vs. bronze/stainless steel for potable domestic hot water), and port-to-port dimension (typically 6-1/2 inches for standard residential circulators).
When upgrading from a legacy fixed-speed circulator to an electronically commutated motor (ECM) high-efficiency pump (such as the Grundfos ALPHA or Taco 00e series), confirm control signaling requirements. Modern ECM circulators feature auto-adapting differential pressure modes that adjust speed automatically, reducing electrical consumption while maintaining zone flow balance.
2. Three-Speed Wet-Rotor Circulator Cross Reference
| Grundfos | Taco | Bell & Gossett | Armstrong | Wilo | Port-to-Port / Flange Size |
|---|---|---|---|---|---|
| UPS 15-58 FC | 007-F / 0015-3F | NRF-22 / NRF-36 | Astro 230CI | Star S 21 | 6-1/2″ (2-Bolt GF 15/26 Flange) |
| UPS 26-99 FC | 0011-F / 0013-F | NRF-45 / PL-55 | Astro 280CI | Star S 33 | 6-1/2″ (2-Bolt GF 15/26 Flange) |
| ALPHA 15-55F (ECM) | 0015e3 / VIRTUO | ecoCirc 20-18 | Compass H | Stratos PARA | 6-1/2″ (2-Bolt GF 15/26 Flange) |
3. Single-Speed & High-Head Circulator Cross Reference
| Grundfos | Taco | Bell & Gossett | Armstrong | Wilo | Port-to-Port / Flange Size |
|---|---|---|---|---|---|
| UP 15-42 F | 005-F / 008-F | NRF-9 / SLC-30 | Astro 20 | Star S 16 | 6-1/2″ (2-Bolt GF 15/26 Flange) |
| UP 26-64 F | 0010-F | NRF-33 / PL-36 | Astro 250 | Star S 25 | 6-1/2″ (2-Bolt GF 15/26 Flange) |
| UP 26-116 F | 0013-F | PL-50 | S-25 | Top-S | 8-1/2″ (2-Bolt GF 40/50 Flange) |
4. Discontinued / Legacy Circulator Replacement Guide
Older single-speed circulators can be upgraded directly to modern 3-speed or ECM equivalents. The table below outlines direct replacements specified in the Grundfos UP Series Technical Literature (Lit. 5235400).
| Legacy / Discontinued Model | Original Manufacturer | Recommended Modern Replacement | Notes & Flange Adapter Info |
|---|---|---|---|
| UP 15-18 F / UP 15-42 F | Grundfos | UPS 15-58 FC / ALPHA 15-55F | Direct drop-in. Set 3-speed switch to Speed 1 or 2 to match legacy flow. |
| Series 100 (3-Piece Design) | Bell & Gossett | NRF-22 or Grundfos UPS 26-99 FC | Verify physical clearance; 3-piece pumps take more space, but wet-rotor replacements use standard 6-1/2″ port-to-port flanges. |
| 007-F5 (Legacy Single Speed) | Taco | Taco 007-F or Grundfos UPS 15-58 FC | Standard 1/20 HP hydronic replacement. Matches standard 2-bolt flange. |
| S-25 / H-32 | Armstrong | Armstrong Astro 280 / Grundfos UP 26-116 F | Confirm system total dynamic head (TDH) before replacing high-head cast iron circulators. |
5. Source Reference Documents & Resources
Source Reference Documents (PDF):
Related Resources & Categories:
6. Source Your Circulator Pumps From TCI Supply
We ship these products worldwide! Delivery is normally stock. Request a Quote now or call us at 1-800-755-2883 for expert assistance.
Cross-references are provided as a selection aid. Hydronic pump replacements require matching voltage, casing material, flange size, and head/flow requirements. Always verify system parameters before ordering replacement units, or call us and we’ll verify it with you.