BLFC and DLFC identify different hydraulic paths. A brine-line flow control regulates the brine/refill path; a drain-line flow control regulates drain or backwash flow. Matching thread or diameter does not make their buttons interchangeable.
Side-by-side identification
| Control | Path | Selection data | Fleck 5600 examples |
|---|---|---|---|
| BLFC | Brine-line/refill circuit | Valve model, refill flow rate, fitting/module, and system salt setting | 12094 .25 GPM, 12095 .50 GPM, 12097 1.0 GPM |
| DLFC | Drain/backwash circuit | Tank/media requirement, backwash flow, drain fitting, line length, and valve model | The 5600 table says “DLFC button, specify size”; it is not one of the BLFC numbers above. |
Symptom is not a size specification
A brine-level or drain symptom can be caused by restriction, pressure, controller position, injector condition, or an internal leak. Preserve the installed rate and verify it against the system specification instead of increasing or decreasing flow from the symptom alone.
What to photograph
- Valve-body and controller labels.
- Markings on the flow button or complete module.
- Brine and drain connection locations.
- Tank size, media type, and current system specification from the installer record.
Service safety and limits
These checks identify a valve and narrow a parts search; they are not a substitute for the manufacturer service procedure. Before opening a valve, use the documented bypass procedure, isolate water, relieve pressure, and disconnect power. Water-treatment valve service should be performed by a qualified person. Stop if the label, flow direction, wiring, or part suffix does not match the cited manual.
Primary source
Pentair Fleck 5600 Service Manual, document 40106, job specification items 7–9, printed page 14 items 35–45, and accessories page 18.
Revision status: no superseding revision is asserted. Verify the revision block in the linked manufacturer document. Evidence reviewed September 28, 2026.