Gremllin in my water pump.

Old-Biscuit wrote:

Yosemite Sam1 wrote:
Thanks everyone for the input. I'll check into those as my son promised to look into it when he comes visit us.

He also suspected the fuse is blown and it is just not apparent by just looking at it through the red cloudy plastic case. He said it is still supposed to continue working if the fuse has not blown.

Auto blade type fuse has 2 small openings on top of plastic case that are direct contacts with each side of fuse

Fuse installed......voltmeter 12VDC ---should read if not blown
Fuse NOT installed...voltmeter ohm.....should read 0 (zero) if NOT blown ----reads 1 or OL then fuse is bad

Another good information. I'm learning a lot with this post and your responses.

Thanks!

Yosemite Sam1 wrote:
Thanks everyone for the input. I'll check into those as my son promised to look into it when he comes visit us.

He also suspected the fuse is blown and it is just not apparent by just looking at it through the red cloudy plastic case. He said it is still supposed to continue working if the fuse has not blown.

Auto blade type fuse has 2 small openings on top of plastic case that are direct contacts with each side of fuse

Fuse installed......voltmeter 12VDC ---should read if not blown
Fuse NOT installed...voltmeter ohm.....should read 0 (zero) if NOT blown ----reads 1 or OL then fuse is bad

Dutch_12078 wrote:
I've seen fuses used in mobile applications fail over time just from vibration. The giveaway when the fuse is dissected is that the fuse wire is detached from one end cap with no signs of any arcing. Glass fuses seem to be the most prone to that.

Yeah, that's another possibility and made sure the clips are still tight.

I've seen fuses used in mobile applications fail over time just from vibration. The giveaway when the fuse is dissected is that the fuse wire is detached from one end cap with no signs of any arcing. Glass fuses seem to be the most prone to that.

Thanks everyone for the input. I'll check into those as my son promised to look into it when he comes visit us.

He also suspected the fuse is blown and it is just not apparent by just looking at it through the red cloudy plastic case. He said it is still supposed to continue working if the fuse has not blown.

Look up the specs on your brand/model of pump
Probably lists 7.5a or 10a

Pump stopped working but started working when you swapped fuses from 10A to 15A
That is because the 10A fuse had blown

Shurflo 4008 requires Minimum 10A Fuse (7.5A full load)
Shurflo 4048 requires Minimum 10A Fuse (9a full load)
Course that is with correct wire size.....12ga recommended

AquaJet ARV & AES Series...15A Fuse
AquaJet ES Series....10A Fuse


So what is your pump???

Recently just went through this.

old shurflo 2088-403-144 original pump that was standard in everything. switched to the the same thing in the updated model. shurflo revolution series.

the hum is more then likely the microswitch. if you wiggle the pump wire where the switch lives on the pump from the chassis it might run normal then go back to humming.

I was in a need to use the pump situation and wired directly to the pump bypassing the switch (2 wires on the motor itself +and-). Problem with this is you have to use the switch in your rv to control the pressure. (not good, but works in a bind.)

to further diagnose your pump wire direct to the motor and see if it works. bypassing the switch.

the microswitch is a omron switch that when pressured up opens the contact turning off the pump. they are replaceable for like 10$ on amazon. overtime it looks like water migrates in switch housing and corrodes the switch thus not making proper contact. thus humming begins. It won't draw enough amps to blow the fuse.

My issue was the pump was leaking at its seals and needed replaced anyway so i bought a new 70$ pump. My pump was in a terrible location and i moved it to a easier spot.

Bottomline your buying a new pump or try to dissassemble your pump and replace your microswitch

here is a switch link microswitch

in the picures on this listing you can see one wire comes from pump motor into switch other wire is chassis positive.

My water pump says to use 10a. The fuse is wired right next to the pump.

I think you're looking at your electrical panel and someone wrote 15a on the label?

Old-Biscuit wrote:

Yosemite Sam1 wrote:

agesilaus wrote:
How did you check the fuse, just a visual inspection may not reveal a blown fuse you need to use a meter to check the resistance.

I did not bother finding out it was under-rated and may give out anyways when it's most inconvenient, lol.:o

True
BUT blown under rated fuse could have been the gremlin

Visual inspection can miss a blown fuse many times
Question is....why did it blow
Cause it was under rated OR because pump motor is drawing to much amperage ?????

To my simple non-electrical engineer mind, the fact that it was under-rated is already a concern as it could fail anytime. My question is, why did the manufacturer even do that?

Yosemite Sam1 wrote:

agesilaus wrote:
How did you check the fuse, just a visual inspection may not reveal a blown fuse you need to use a meter to check the resistance.

I did not bother finding out it was under-rated and may give out anyways when it's most inconvenient, lol.:o

True
BUT blown under rated fuse could have been the gremlin

Visual inspection can miss a blown fuse many times
Question is....why did it blow
Cause it was under rated OR because pump motor is drawing to much amperage ?????