Download it here. The app is searchable in the Google Play Store under Sailboat Owners.
Sorry iPhone/iPad users, we are still waiting on Apple. :(Click the X in the upper right corner to make this go away
I think the blowing fuses (this was with the RuleMate 750, the second of the three pumps, right before I replaced it) were because the pump had actually failed. It was not heat build-up blowing the fuses because it happened far too fast (probably less than 5 seconds). I assumed the real problem caused the failure, and the failure caused the blowing fuses, although I still can't see how. As you pointed out, with a DC motor if the voltage is low, the pump will just run slower (unlike an AC induction motor, where the amps will increase in proportion). My first thought was that the impeller had jammed, but as I said before it turned very freely.Actually this is backwards. With a DC motor, such as a bilge pump, as voltage goes down so does the current, even stall or in-rush current is dictated by the voltage the motor sees. High resistance at the fuse can actually serve to melt the fuse but this is not because of an over current situation just high resistance and the heat developed..
A bilge pump blowing fuses likely has a leak and the bearing surfaces are becoming sticky. As a bilge pump or any typical DC motor stalls or has a load applied the current of the motor goes up. Bilge pump makers size the fuse to intentionally trip if the rotor is over loaded and drawing too much current so the pump does not catch fire.. With a constant power source, such as an inverter, as voltage goes down the inverter draws more current to maintain the same output but with a DC motor as voltage goes down so does current.
Why do you have a float switch on a Rule automatic pump? First you need to get the wiring correct.
Battery positive terminal>fuse (within 7") > AUTO-OFF-MANUAL switch > BROWN wire to AUTO POSITION > BROWN W/WHITE trace to MANUAL POSITION > BLACK to BATTERY NEG.
No float switch...
Once the float switch is removed the scenario I would start with is that the pump may be suffering from drain back cycling due to a poorly designed bilge pumping system.
As a marine electrician customers can't even pay me to install any of the "auto-sensing" bilge pumps. I simply will refuse the work unless they decide to do it correctly. I will also refuse to install any current Rule float switch.
A "properly" designed bilge pumping system for a boat over 25' will look like this.
Emergency Pump = Largest Rule or other centrifugal pump you can physically fit. Pair it with an Ultra Safety Systems Junior or Senior float switch set at a higher level. (IMPORTANT: DO NOT USE CHECK VALVES ON CENTRIFUGAL PUMPS)
Nuisance Water Pump = Diaphragm pump (check valves are okay on diaphragm pumps) and an Ultra Safety Systems Junior or Senior float switch set for lowest desired water level. Note: All wiring for electric pumps shall be sized for no more than a 3% voltage drop.
Manual Pump = Henderson/Whale etc. with no check valve just a strainer.
As I said elsewhere, the (current) issue isn't that the pump doesn't run when it should, it's that it runs (very briefly) when it shouldn't. Neither the level nor the manual switch is calling for it to run.
These were (the first two) Rule Mate pumps with the internal electronic high/low sensor, and I couldn't agree more that they aren't reliable in a dirty bilge. I think the original "won't start when it should, won't stop when it's empty" problem was these sensors and a dirty bilge. The ones I had are not the pumps that start every 2.5 minutes to check for water, and the current Attwood Sahara doesn't do that either. Besides, the interval now is between 10 minutes and an hour (or maybe more; I'm not always listening for it). Nowhere near as frequent as 2.5 minutes. If it were that often, I'd have tried the multimeter test long ago.Rule "automatic" pumps cycle on every 2.5 minutes to check for water. If they "sense" water they continue to pump until they sense less resistance and stop pumping. Rule "mate" pumps use a high and low sensor for on & off. These sensors are certainly not the most reliable I have seen especially in dirty bilges.
That's sort of correct, though mostly incorrect. Were the pump unable to overcome the static head pressure within the discharge line, it wouldn't be able to overcome that head pressure under any circumstances. What actually happens to a pump under the circumstances you describe is that the closed check valve, with the head pressure sitting atop it, prevents the volute (pump body) of the pump from filling with water, and a centrifugal pump which is air-bound in that manner cannot pick up prime. (I can, and have, create exactly the condition of describe within a water well where the pump sits with 50 feet submergence, which is why you're sort of correct, though for the wrong reason.)And, while we are on this fun topic, NEVER install a check valve on a bilge pump discharge hose. I know never is a strong word, and it would seem like a logical thing to do, BUT - in my opinion, by the time the discharge hose is long enough to hold enough water to force the pump to cycle it is holding so much water (which is really heavy) that the pump cannot overcome the static pressure of the water column behind the valve. In this case, I would elect a shorter route and suffer the aesthetics of another through-hull fitting.
Boat manufacturers use them because they are cheap, cutting corners, not following the ABYC standards, or refuse to design and install a proper bilge pumping system. They do this despite the bilge pump manufacturer telling them not to. The ABYC does allow check-valves, for certain situations, (eg: it would be fine on most diaphragm pumps) but not when a manufacturer says not to.Those who are religiously anti-check valve should answer why boat manufacturers use them, as well as answering why they do not object to their use within vented loops on things like their head toilet. (The vent is a check valve.)