How to seal the manual override wire on a Xylem Rule bilge pump
Xylem’s Rule Automatic Bilge Pumps and Rule-Mate bilge pumps include a brown and white striped manual override wire that allows the pump to run continuously when connected directly to a battery. If your vessel, such as a dinghy or small rowboat, does not have a panel switch, or if you simply don't need this feature, the wire must be properly sealed to prevent water from entering and damaging the pump. This video and guide walk you through the correct way to seal the manual override wire using silicone caulking, adhesive-lined heat shrink tubing, and a heat gun. The process takes only a few minutes and provides a reliable, waterproof seal.
What Is the brown and white wire on a Rule bilge pump?
The brown and white striped wire on Rule Automatic Bilge Pumps (including Rule-Mate models) is the manual override wire. When connected directly to a positive battery source, it bypasses the automatic float switch and runs the pump continuously.
When you might use it:
Small vessels without a panel switch, such as dinghies or rowboats, can wire the brown wire directly to the battery for manual pump operation.
When you should seal it:
If your installation does not require manual override, do not leave the wire exposed. An unsealed wire end can allow water to travel down the conductor and into the pump housing. Always seal unused wires before completing the installation.
Important: Do not connect only the brown wire without also using the white wire. Doing so will cause the pump to run continuously, which can burn out the motor. If you do not need the manual override function, seal the wire as shown below.
What You Need
- Silicone caulking (marine-grade recommended)
- Adhesive-lined heat shrink tubing (adhesive-lined provides the best seal)
- Heat gun
How to Seal the Manual Override Wire: Step-by-Step
Step 1: Slide the heat shrink tubing onto the wire.
Before applying any caulking, slide a length of adhesive-lined heat shrink tubing over the end of the brown and white wire. Leave it pushed back from the wire tip so it doesn't interfere with the next step.
Step 2: Apply silicone caulking to the wire end.
Apply a generous amount of silicone caulking to the exposed end of the wire, making sure to cover it completely on all sides. Full coverage is key to creating a watertight seal.
Step 3: Slide the heat shrink tubing over the caulked end.
Carefully slide the heat shrink tubing down and over the silicone-covered wire end. Move slowly to avoid scraping off the caulking. Position the tubing so the wire end sits roughly at the midpoint of the tube.
Step 4: Apply heat to shrink the tubing.
Use a heat gun to shrink the tubing evenly around the wire end. As it contracts, you should see the silicone caulking begin to squeeze out slightly from the ends — this confirms a tight, well-sealed fit. The combination of heat-shrink adhesive and silicone provides a double layer of water protection.