Replacing Shower Sump Float Switch With Manual Switch

The Rule-A-Matic Plus float switch in the shower sump on my 2012 R27 failed ON no matter the position of the float. The only way to stop the shower sump bilge pump from running was to remove the fuse for it in the Power Distribution Panel under the port side hinged step.

From all of the posts about it here on Tugnuts, that float switch has a poor service record of failing OFF or ON or the float sticking in the UP or DOWN position. Several Tugnutters have removed that float switch from the sump box and installed a manual ON/OFF switch.

I made that modification on my boat today. It should be done ONLY on boats that have a shower sump that serves ONLY the shower. On some boats, especially the bigger ones, the shower sump also serves the air conditioning condensate drain. On those boats, this modification SHOULD NOT be made.

Here are the steps I took to make the modification on my R27 Classic. The R25 Classic may be similar. For the manual switch, I used a SPST (Single Pole Single Throw) ON/OFF toggle switch. It has a gasket around the switch operator and is water resistant. Some Tugnutters have opted for a spring loaded ON/OFF switch. Your choice.

1) Remove the shower sump bilge pump fuse from the Power Distribution Panel.

2) Take out the triangular removable floor under the cabinet. It is not fastened down in any way and has a small round pull hole on the apex of the triangle.

3) Remove the top from sump box. The front two screws are easy access Phillips head. The back two are almost blind and require a very small stubby phillips or a right angle Phillips, plus lots of patience.

4) Clean the sump box. Depending on use, it may be pretty gross.

5) Remove the float switch by removing the easy access Phillips head screw on the port side of the float switch (it’s to YOUR right as you face the sump box looking aft). The other Phillips screw on the starboard side of the float switch is not easy access, but it DOES NOT have to be totally removed. That side of the float switch has a U-shaped hold down. Just loosen the screw a little and pull out the float switch.

6) Cut the two wires from the float switch. Those two wires will be run to the newly installed manual switch.

7) Crimp a butt splice on each of the two wires cut from the float switch. I used heat-shrink butt splices. Then crimp a long piece of wire to the other side of each butt splice. The wire should be long enough to run to the location of the manual switch. I located the manual switch on the front of the cabinet between the cabinet door frame and toilet flush panel. The wires on my installation had to be long enough to run from the sump box across the underside of the cabinet floor and up the inside front of the cabinet.

8) Drill a hole in the the removable floor support frame big enough for the wires running to the manual switch to pass through. Using a hole saw, make a semi-circular cutout on the edge of the removable floor for the wires to pass through.

9) These instructions are for an ON/OFF toggle switch. Modify them if you elect to use another type of switch. Drill a hole for the barrel of the switch to pass. Before drilling the hole, countersink it to prevent chipping the surrounding gel coat.

10) Run the wires up to the switch and fasten them to it. I used adhesive back nylon cable clips to secure the wires to the inside face of the cabinet.

11) Put the barrel of the switch through the hole and secure it with the supplied nuts. I placed a washer between the nuts and the gel coat.

12) Re-install the shower sump bilge pump fuse.

I’m certain that some Tugnutters will point out that the float switch does not HAVE to be removed from the sump box— the wires to can be cut without removing the sump box cover. However, you better be damn sure what wires you’re cutting. Removing sump box cover and the float switch allows positive identification of what wires you’re cutting. And the sump box will likely need a good cleaning. Removing the float switch allows for that.

If you choose to make this modification, good luck! Here are two pictures from my project:



This shows the wiring coming up through the removable floor support and the edge of the removable floor. I may replace the nylon cable clips with flat plastic cable conduit if the nylon clips interfere with what I store in the cabinet. The cable clips for some reason look bigger in this photo.



This is where I located the switch. Being a pilot for 40+ years, I can’t stand unlabeled switches.

Nice write-up Bill, thank you. Mine still works but I’m putting it on my winter to-do list. It’s not a matter of will it fail but WHEN is it going to fail.

Tim and Donna
Gratitude

2015 R-27
My switch also failed and I did the same. Works great! Hardest part of the job was getting the lid to sump off.

I had installed a switch as well. I used a different approach and used a different type switch. For the switch I used a spring loaded rocker switch that is always off until pressed on. I figured this would avoid any accidental engagement of the pump. I also left my float in and installed the wiring by intercepting the power line going to the sump. It eliminated even having to get into the sump. I figured if it is in a stuck operating position I will continue to use the switch. If it should ever decide to work properly again it won't work unless I engage the switch.