5 amp fuse blowing (pump)

[Vanman]

Hi, fuse under passenger seat is blowing as fast as I can put them in. It's the first fuse in. No idea where to start fault finding ... no water to taps or toilet any hints / ideas please?

 

[Cush]

Guessing it’s the pump and that it’s an in tank pump?

I would try to isolate the pump, removing and insulating the ends. If it doesn’t blow then it would indicate a faulty / shorting pump. Just my 2p worth. Good luck

 

[Reallyretired]

Mines 10A and that's what it's supposed to be according to the manual. Yours may be different but are you sure 5A is correct?

 

[BouncyBoatFolk]

IF it's a pump in the tank ( submersible) it has probably seized. Spin the impeller by hand, and also a gentle tap on their side can free them up.

 

[glascoed]

5amp does sound a bit small for a pump. Mine was 7.5. Has the pump ever been replaced? Many regard them as a consumerable maybe it was replaced with a more powerful one.

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[Richard n Ann]

My punp has a 10 amp fuse. It runs at about 4

 

[Happy Jack]

If it's been ok up to now then yes the pump may well be at fault.
You could try a 7A fuse and see if it runs.

 

[Vanman]

Thanks. It is a submersible pump and I replaced it a couple of weeks ago as the last one had seized. The new one worked for a few days. I tried a 7.5 and 10 before asking here but they blew just as quick. It was rusty nail or here next! I'm travelling today so will try spinning the pump tonight.

Is there any easy way of turning off when replacing a fuse, or is that not necessary? Ta.

 

[Cush]

Is there any easy way of turning off when replacing a fuse, or is that not necessary? Ta.

No switch in the control panel? Can you power off the entire control panel? Are any of the connections to the pump in the water?

 

[Happy Jack]

My 5A fuse on the sink pump blew.
Replaced it but although it didn't blow still no water.

Found wire out of this wago connector.
Guess high resistance because it was loose.
Now got proper crimp connectors.
Might be worth looking for loose connections and if still no joy might be worth pulling the pump out and bench testing it

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[BouncyBoatFolk]

Hi, fuse under passenger seat is blowing as fast as I can put them in. It's the first fuse in. No idea where to start fault finding ... no water to taps or toilet any hints / ideas please?

If pump wiring is easily accessible disconnect the pump and try a new fuse, from memory just the pump is on that circuit.
Mike.

 

[thenomad]

If pump wiring is easily accessible disconnect the pump and try a new fuse, from memory just the pump is on that circuit.
Mike

Most motor pumps run at about 5 amps but will have a current search around about 7 to 8 amps which is probably why you keep blowing fuses I would fit 10 amp fuse has running the pump and a toilet at the same time will probably come close to it

 

[Cush]

Most motor pumps run at about 5 amps but will have a current search around about 7 to 8 amps which is probably why you keep blowing fuses I would fit 10 amp fuse has running the pump and a toilet at the same time will probably come close to it

Post #8, OP tried 10 amp.

 

[Richard n Ann]

Seized up motors tend to pop fuses but it's new so lord knows. My caravan one got stuck a few years ago so it's a common fault, there's probably zero starting torque so it might just need a shove

 

[StitchUp]

Hi, fuse under passenger seat is blowing as fast as I can put them in. It's the first fuse in. No idea where to start fault finding ... no water to taps or toilet any hints / ideas please?

Continually blowing a fuse is a PITA - whenever I'm confronted with this problem I replace the fuse with a resettable fuse for the purposes of testing and replace with a standard fuse when the fault has been rectified. Resettable fuses are available on Amazon of course.

https://www.amazon.co.uk/Mintice-Circuit-Automotive-Resettable-Protection/dp/B07HNV4DYC/?tag=mhf04-21

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[David and Sally]

Disconnect the pump at the connections nearest to the pump. Does the fuse blow? If it does it is the wiring somewhere to the pump. If not it may well be the pump.

Run a separate fused ( say 10a )power directly to the pump 12v +ve to test pump. If all ok reduce the fuse values to test the working amperage.

 

[Vanman]

Just to keep me off balance, the pump did feel stiff but after a few twists I put a new 10a fuse in and tried the tap (turning the control panel off first) it didn't pump, but it didn't blow the fuse either... The wiring is under the bed so pretty hard to get at.

 

[Vanman]

I have a spare pump with me so I'll dismantle the bed, check the wiring to the existing one (it's crimped spades) and replace the pump if necessary. May have to be a click block though as not sure I carry a crimping tool.

 

[Vanman]

Well, Arrived for tonight's stop, unmade and dismantled the bed ... swapped the pumps over (I didn't have any crimps with me so just twisted cable connections to try it out) new 10 amp fuse in and the bleeding thing started working. Just then it started raining cats and dogs and I found I had no electric tape so Gorilla tape had to do. Twisted connections and Gorilla tape, my bodging has hit an all time new low be a miracle if it lasts long but it's working today!