GRUNDFOS · BOILER FEED
Stainless Steel Bypass Orifices for Continuous Feed Boilers
Grundfos stainless steel bypass orifices that keep the minimum flow through a CR boiler feed pump on a continuous feed boiler: 1/16 to 1 in orifices, 1/2 in, 3/4 in, 1 in and 1 1/2 in threads.
CR, CRI, CRN 1s to 95
1/16 to 1 in Orifice
Stainless Steel
1/2 in, 3/4 in, 1 in or 1 1/2 in Thread
Sized by Pump, Stages and Temperature
Overview
On a continuous feed boiler the feed pump runs against a closed valve part of the time. A bypass orifice returns a fixed flow to the feed tank so the pump never drops below its minimum flow. Grundfos sizes the orifice by pump model, number of stages and liquid temperature; the minimum flow, the recommended bypass line and the orifice are all in the Grundfos price list table.
What Ships and What It Needs to Run
Included: one stainless steel bypass orifice of the size and thread in the selected option (Grundfos price list).
Threads: the 1/2 in tap version has G 1/2 and 1/2 in NPT threads; the 3/4 in NPT tap version has 3/4 in NPT on both sides; orifices 9/16 to 3/4 in have 1 in NPT threads and 13/16 to 1 in have 1 1/2 in NPT threads (Grundfos price list).
Genuine Grundfos equipment, factory-new in original packaging — sold and supported by Watermain Supply, an independent industrial supplier.
Warranty: 24 months from date of installation, but not more than 30 months from date of manufacture (Grundfos limited warranty). Grundfos repairs or replaces its own product; costs of removal, installation and transportation are not covered, and products sold but not manufactured by Grundfos carry their own manufacturer’s warranty.
Specifications
| Specification |
Value |
| Product |
Stainless steel bypass orifice for continuous feed boiler service |
| Orifice sizes |
1/16 to 1 in |
| Threads |
1/2 in tap: G 1/2 and 1/2 in NPT; 3/4 in NPT tap: 3/4 in NPT both sides; 9/16 to 3/4 in: 1 in NPT; 13/16 to 1 in: 1 1/2 in NPT |
| Temperature bands |
5-176°F, 177-210°F and 211-250°F (251-356°F with the Cool-Top shaft seal) |
Orifice Range by Pump
| Pump |
Recommended bypass line |
Orifice range (by stages and temperature) |
| CR(I,N) 1s |
3/8 in |
1/16 to 1/8 in |
| CR(I,N) 1 |
3/8 to 1/2 in |
3/32 to 5/32 in |
| CR(I,N) 3 |
1/2 in |
3/32 to 3/16 in |
| CR(I,N) 5 |
1/2 in |
1/8 to 1/4 in |
| CR(I,N) 10 |
3/4 to 1 in |
1/8 to 3/8 in |
| CR(I,N) 15 |
1 to 1 1/4 in |
3/16 to 7/16 in |
| CR(I,N) 20 |
1 to 1 1/4 in |
3/16 to 1/2 in |
| CR(N) 32 |
1 1/4 to 1 1/2 in |
1/4 to 9/16 in |
| CR(N) 45 |
1 1/4 to 1 1/2 in |
5/16 to 5/8 in |
| CR(N) 64 |
1 1/2 to 2 in |
3/8 to 13/16 in |
| CR(N) 95 |
1 1/2 to 2 in |
7/16 to 1 in |
Summary of the Grundfos bypass orifice tables; send the pump model, stages and liquid temperature and we will confirm the orifice and bypass line.
Before You Buy — The Limits That Decide the Fit
| Check |
What decides the fit |
| Orifice size |
Use the Grundfos table for your pump model, stage count and liquid temperature; the orifice depends on all three. |
| Bypass line |
Pipe the bypass with the line size Grundfos recommends (based on 50 ft of line); a smaller line changes the bypass flow. |
| Grundfos orifices |
Orifices other than those supplied by Grundfos may have different flow and head characteristics (Grundfos price list). |
Applications
Minimum-flow bypass for Grundfos CR, CRI and CRN boiler feed pumps on continuous feed boilers (Grundfos price list).
