Melted Water Pump Fuses November 20, 2017, 03:34:55 pm Having the usual problems with my Shurflo water pump in my 2006 23.5' TK, and (not) looking forward to my second pump change-out. The new one I picked up is an Shurflo Aqua King II, Model 4148....anyone used one of these, had any issues or problems, or have any suggestions for installation?My actual question concerns the popping 15A fuses I experienced before the existing pump failed on a recent trip. I changed out 4 fuses over 4 days, turned the pump on and off after every use (which has worked in the past to help cope with the pump), but this time each fuse body was actually partially melted when it failed, which I have never seen before. The fuses are from a large quantity I bought on E-bay, so are most likely Chinese cr@p, but I have never had any fuses fail this way, and wondered if anyone else had experienced this or had an explanation. The fuse panel looks fine - no damage from the melted fuses. Any help or advice would be appreciated!
Re: Melted Water Pump Fuses Reply #1 – November 20, 2017, 04:03:12 pm I'd check the pump wiring from one end to the other. There's likely a short to ground.Mark
Re: Melted Water Pump Fuses Reply #2 – November 20, 2017, 04:29:05 pm I think Mark may be right, but the problem may be in the pump itself. Checking is easy. Disconnect the wires going to the pump at the pump. Put in a new fuse. Turn on the switch. If the fuse remains ok. the problem is in the pump. If the fuse fries, the problem is in the wiring.Ken F in NM
Re: Melted Water Pump Fuses Reply #3 – November 20, 2017, 06:12:48 pm A good rule of thumb for fuses or circuit breakers is if you have to replace a fuse, or reset a breaker, and then either blows\trips again, it's time to look for an explanation. I agree with Mark and Ken, if you replace the fuse, turn on the pump and it blows again immediately, a dead short makes sense. From your description of the problem, though I may misunderstand, it sounds like when you replaced the fuse each time, it wouldn't blow again right away. If so, the melting indicates there may be excessive heat causing, or at least contributing to the fuse failure. This may be due to a motor problem, a loose connection either at the fuse panel, at the pump, or one of the connections to it. Maybe even a wire damaged somewhere between the fuse panel and the pump (any problems with small rodents in the coach?). If you follow Ken's troubleshooting advice, and find that the motor is bad, I'd be sure to carefully check all of the connections from the fuse panel to the new pump before applying power again. The motor failure may be the result of another problem.
Re: Melted Water Pump Fuses Reply #4 – November 20, 2017, 09:45:54 pm So, a little update after removing the old pump (Smart Sensor 5.7 Model 5901). I had forgotten that there was an in-line 15A fuse in the red (positive) wire leading out of the pump. Despite blowing (and melting) three 15A fuses in the coach fuse panel over a few days, the fuse in the pump wiring was perfect.So apparently, that leaves the positive side of the wiring out of the picture - correct? Would a fault in the pump somehow effect the ground and blow the fuse in the panel? My very limited knowledge of vehicle electrical systems is a real handicap. I was told by a tech at Shurflo a few years ago that the problem causing the blown fuses was with some sort of demand mechanism in the pump which could be adjusted by turning a screw in the front of the pump (completely inaccessible when the pump is in place). There are 5 phillips-head screws on a plate covering the front of the 5901, with one in each corner of the plate and one in the center. Is this the screw the Tech told me to turn 1/4 turn clockwise to keep from blowing fuses? Any way to test the old pump once the adjustment is made so it can be carried as a spare, or should I just toss it?The new pump (Aqua King II, Model 4148) has a hex screw in the center front location, but the installation instructions warn not to adjust it unless I have some sort of elaborate testing equipment. The new pump is 4.0 GPM vs. 5.0 GPM - should the new pump function adequately in the LD? Is the 4148 the current recommended replacement, or is there something better out there now?The new pump mounts in exactly the same way as the old one, the only difference being a smaller filter/strainer housing. Should I use the new filter that came with the 4148, or the much larger unit from the old pump? Either one will fit.Sorry to get so far in the weeds on this, but the inside of my rig looks like an explosion took place there, with drawers and parts strewn everywhere, so I want to make sure I get this as right as I can before I button everything up again. As always, thanks for sharing your knowledge and experience!
Re: Melted Water Pump Fuses Reply #5 – November 20, 2017, 10:32:42 pm "From your description of the problem, though I may misunderstand, it sounds like when you replaced the fuse each time, it wouldn't blow again right away. If so, the melting indicates there may be excessive heat causing, or at least contributing to the fuse failure."Once a fuse melts in the fuse holder, suspect the fuse holder has a problem. A poor fuse or breaker connection can produce a lot of heat, burning or melting things.Before going any deeper, have you tried hot wiring the pump? It may not be bad.If it is still good, I would be temped to put the old pump back in and carry the new one as a spare.The old pump is likely to develop leaks if saved and used as a spare, old seals will do that.If you continue using the old pump, make sure there is adequate Factory wire and hose available to connect the new pump, if field installed. Hate to find out that a hose is an inch short.The new pump should be adequate. Use the new filter, the old one is more prone to problems, due to its age.Major projects always seem to make huge messes but it will all go back to together quickly, one you are done.Larry 1 Likes
Re: Melted Water Pump Fuses Reply #6 – November 21, 2017, 02:09:56 am One thing I'd want to be sure of is that no other items except the waterpump are running off of the fuse in the distribution panel. Just because the pump is all that is listed doesn't mean a light or something else isn't putting more load on that fuse, than just the pump. That could be why the fuse at the pump looks to be in better condition. RonB
Re: Melted Water Pump Fuses Reply #7 – November 21, 2017, 10:10:41 am I'm with Larry - the fuse element should not melt its casing before the element opens, regardless of nationality. You will likely find a problem with the connection of the fuseholder clips, and the board will have to be removed to repair that.Steve
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Topic: Melted Water Pump Fuses (Read 217 times)
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