Water pump circuit designed to fail?

[Will Hansen]

(Fuses seem to be beating me up lately.) My wife has an uncanny ability to blow the fuse on our water pump while taking showers. And this makes her mean and loud! So, to try to improve my life, I decided to investigate. But what I've found seems strange.

The fuse in question is a 10 amp fuse in one of the Multiplex modules above the toilet. Our water pump is an Aquajet II model 55-aquajet-arv rated at 10amps max.  At first glance that looked like the problem: the pump operating properly at its max would blow a 10 amp fuse.   And the solution would be to change to a 15amp fuse. (Or 12.5 if I could find one) But when I went to implement that plan I noticed that the Multiplex module labels that circuit (and all the others) at 10 amp max. 

So what's a guy to do? This seems like 'failure by design'! 

I do note that there is a paper label amending the amp limit to 15 on one of the fuses on one of the other modules.  While it looks official, I hesitate to simply boost my water pump fuse and cross my fingers that I don't toast my Multiplex circuit.

[Jerry Carr]

Hi Will,
I like your question, we have an 06 PT and have not had this problem like this but understand your wife's reaction(not fun).
FYI I did have to increase a fuse size on our air compressor when I did an upgrade. I ran a new hot wire to the air pump by adding a new fuse in the rear electrical bay (this uses household style circuit breakers). It's just a thought you should have spares in your panel.
Let see what the pro's on the forum advise I am sure they will have a reasonable recommendation for you.
We hope to see you at some of the NW rallies.
   

[Lee Welbanks]

Will,  I'm not sure but I think that 10 amp fuse is to power up a relay that powers the water pump, I've never had a problem with our pump which is the same as yours. I've went through the front run box and rear run box pictures I have and did not see a relay or anything labeled water pump. That doesn't surprise me as I've found a few things on this coach that are a head scratcher as to how they are powered.

[Bryan Beamon]

Will, our 07 Contessa" use's a 15 amp fuse for the water pump and has been fine for 11 years. Many years ago we were contantly blowing  15 amp fuses on our original water pump and was told by the pump manufacturer to replace the pump.fyi

[Keith Moffett]

Will
Sounds to me like the pump is working too hard.
IMHO I would look at the pump but also the pump screen and supply lines to be sure of a free flow water supply.  If your screen filter is 3/4 blocked you would get enough water for a sink but the shower would draw more and the pump work harder.  Could be a simple cleaning of the filter screen.

[Fred Brooks]

    Hi Will,
The Aqua-Jet pump is a variable speed water pump that operates on water flow and pressure demand. Is the fuse blowing when the pump is operating  with the kitchen faucet or lavy faucet? It sounds like the internal controller for the pump may be at fault. If you have access to an amp probe meter, check the amp draw at the pump while you simulate the shower operation at the time the fuse blows. The pump draws the most amperage just before it shuts off.
  Hope this helps, Fred