SFDP1-012-035-21
Seaflo 21-Series 1.2 GPM wiring diagram
SEAFLO SFDP1-012-035-21, 12 V diaphragm pump: nominal 1.2 GPM free flow and 35 psi shutoff, with intermittent duty. Use the pump-label fuse; approximately 4 A modeled draw is not the required circuit-protection rating.
- Compatible systems
- 12 V
- Continuous draw
- 4 A
- Surge current
- 6 A
Wiring diagram
How the Seaflo 1.2 GPM is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Cable sizing for this example
Use the diagram as a starting point for your installation. Replace the example equipment and cable lengths with your own, and check the connections against your exact model's instructions.
3 m one way
12 V system
- Wire
- 1.5 mm² · 16 AWG
- Example fuse
- 5 A
- Design current
- 4 A
- Voltage drop
- 2.4%
Sized against ABYC E-11. The design current is the part's continuous draw. The length is one way; voltage drop includes an equal-length return.
Run-length and manufacturer assumptions
The editable example uses 3.048 m (10 ft) runs unless a shorter run is stated. Metric overviews round these to 3 m. Adapt the parts and lengths to your installation before choosing cable and protection.
Supporting parts
- 6.1 m total of 1.5 mm² (16 AWG) marine cable
- Terminations for 1.5 mm² cable, matched to the equipment's screw terminals, leads or studs
- 5 A fuse and holder on the positive run
- Heat-shrink, strain relief and terminal boots sized to the cable
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Reviewed against manufacturer family documentation (rev. Undated manufacturer document; printed revision not established), checked 2026-10-01. Exact variant details still require confirmation. Manufacturer documentation →
21-series model boundary
The catalog identifies the 12 V SFDP1-012-035-21, nominally 1.2 GPM/4.5 L/min with 35 psi pressure-switch shutoff. Free-flow delivery and shutoff pressure are different operating points; it does not deliver its free-flow rating at shutoff. The downloaded SEAFLO-authored guide is the family installation document linked by SEAFLO USA, without an exact suffix-specific electrical table.
Supply and protection
`+` and `−` represent the two motor supply leads. The guide calls for an individual circuit with the fuse or breaker specified on the pump label, and a switch in the positive lead. It mentions a minimum 10 A supply circuit and minimum 20 AWG wire; those are not permission to fit any 10 A fuse to a long 20 AWG run. Use the exact pump label, cable ampacity and voltage-drop calculation. Approximately 4 A in the catalog is a planning load, not a branch-fuse prescription.
Mount and plumb for intermittent use
Fit an adequate 40-mesh inlet strainer, at least 3/8-inch internal-diameter plumbing, and flexible high-pressure hose at both ports. Mount on a solid accessible surface near the tank with ventilation. The pump is intended for intermittent duty; the manufacturer excludes continuous high-pressure reverse-osmosis service. Avoid restrictions that cause rapid cycling and poor delivery.
Commissioning and omissions
Check for suction leaks, clean the strainer and measure voltage at the pump under load before replacing a pump that will not prime or has low flow. Switch its supply off when leaving the boat unattended. Drain/winterize to prevent freezing damage. The drawing omits the pressure switch, internal valve action, strainer and water plumbing. Verify the complete SFDP model and fuse marking before treating the family guidance as an exact installation specification.
Source: manufacturer document — printed pp. 1–4 on PDF pp. 1–2; primary manufacturer family guide linked from SEAFLO USA.
Fit check
Connect it to the rest of your system.
Describe your setup to draft a system with SFDP1-012-035-21 connected. Review the selected parts and cable lengths, then edit the diagram in Crimp.
The model only picks parts and draws the connections. Every wire size and fuse rating still comes from Crimp's own sizing, never from the model.
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Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
SEAFLO SFDP1-012-035-21, 12 V diaphragm pump: nominal 1.2 GPM free flow and 35 psi shutoff, with intermittent duty. Use the pump-label fuse; approximately 4 A modeled draw is not the required circuit-protection rating.
- Compatible systems
- 12 V
- Continuous draw
- 4 A
- Surge current
- 6 A
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
+
positive · input
−
negative · input
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Results use the example current and run length shown above. Set your actual equipment, lengths and installation conditions in Crimp before choosing hardware.
Read how the sizing worksNext step
Plan your installation with Seaflo 1.2 GPM.
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