Fresh water tank pump, dog's dinner

[Anthony1]

I've made a right dog's dinner of my fresh water tank problems.

The 5 amp fuse under the passenger seat has blown twice. Replaced twice.

I finally opened the tank (after buying the expensive tool). I ordered a new pump from 'the shop'. I removed the pump and tested it and it still works.

I have cancelled the new one and now need to connect the old pump to the wiring. Silly me, cut the wires too short.

Any recommendations for connecting said wires, which will be under water.

Thank you

 

[lohr500]

I would obtain some suitable diameter heat shrink tubing.

• Then place a 1 inch length of the heat shrink tube over each cable, away from the joint area.
• Then carefully solder the cables back together.
• Then try to fully encapsulate each of the soldered connections with a coating of two part epoxy resin to fully waterproof the connections. Make sure the epoxy goes past the cable insulation material. You may need to build up the coating in several attempts, allowing each coat to dry before applying the next.
• Then slide the heat shrink tubing over the epoxy once it has set and heat it up to shrink it into place.

I don't think heat shrink tubing alone will guarantee a waterproof joint.

Worst case scenario is that the connections aren't fully waterproofed and will corrode away over time and the fuse may blow if a current flows through the water between the two connections.
It is only low voltage, so no danger of electrocution, etc!.

 

[flying banana]

you can buy 'waterproof wire connectors' screwfix amazon etc. or try 'liquid electrical tape '

 

[capt kirk]

 

[sidepod]

Just solder the wires, tape them then wrap the whole joint in self amalgamating tape.

https://www.screwfix.com/p/self-amalgamating-rubber-tape-black-3m-x-25mm/2115V?tc=NC6&gad_source=1&gclid=CjwKCAjw4f6zBhBVEiwATEHFVrK5r0iq04-BwfxFtnuISmXWphIG1d-XLDmuPChDSGHqcjL1xQDEexoCEyYQAvD_BwE&gclsrc=aw.ds

 

[WelshGas]

I've made a right dog's dinner of my fresh water tank problems.

The 5 amp fuse under the passenger seat has blown twice. Replaced twice.

I finally opened the tank (after buying the expensive tool). I ordered a new pump from 'the shop'. I removed the pump and tested it and it still works.

I have cancelled the new one and now need to connect the old pump to the wiring. Silly me, cut the wires too short.

Any recommendations for connecting said wires, which will be under water.

Thank you

View attachment 125415

Before you rush to refit the old pump. Have you found the cause of the 5 amp fuse blowing?

I presume you tested the original pump using a supply from a 12v battery. Was that supply fused at 5 amps?

The original pump might have developed a high electrical resistance or a higher than normal mechanical resistance that required more than a 5 amp supply to turn the impeller.

 

[sidepod]

https://www.screwfix.com/p/self-amalgamating-rubber-tape-black-3m-x-25mm/2115V?tc=NC6&gad_source=1&gclid=CjwKCAjw4f6zBhBVEiwATEHFVrK5r0iq04-BwfxFtnuISmXWphIG1d-XLDmuPChDSGHqcjL1xQDEexoCEyYQAvD_BwE&gclsrc=aw.ds

 

[flying banana]

Before you rush to refit the old pump. Have you found the cause of the 5 amp fuse blowing?

I presume you tested the original pump using a supply from a 12v battery. Was that supply fused at 5 amps?

The original pump might have developed a high electrical resistance or a higher than normal mechanical resistance that required more than a 5 amp supply to turn the impeller.

i magree ,for the price i would put a new pump in now you've got it out

 

[sidepod]

Pretty sure the pump should have longer tails on it than that?

 

[lohr500]

Those waterproof connectors will only work well if the outer sheath of the clear tube containing the brown and blue cables is both circular and pretty rigid.

Looking at the photo, it appears as though the brown and blue wires are quite a loose fit inside the clear tube and that the tube is more oval shaped than circular.

The connectors rely on compressing a grommet around the circular outer cable to provide a working seal. If you do try to use them, then I would apply a silicon sealer on the ends, once fitted.

But as suggested above, probably worth replacing the pump now you have got so far.

 

[lohr500]

Pretty sure the pump should have longer tails on it than that?

Yes, in his enthusiasm to test the old pump, the OP cut the wires too short

 

[Kimbo]

All these tapes, epoxy etc that people are suggesting should make your morning cuppa taste interesting

 

[yossarian]

For 35 quid I'd get the pump, then you don't need to discover about environmental aviation grade splices.

As @Kimbo mentioned you've still got to consider the food safety of any solution. The pump looks cheap at this point.

 

[Anthony1]

Before you rush to refit the old pump. Have you found the cause of the 5 amp fuse blowing?

I presume you tested the original pump using a supply from a 12v battery. Was that supply fused at 5 amps?

The original pump might have developed a high electrical resistance or a higher than normal mechanical resistance that required more than a 5 amp supply to turn the impeller.

Thank you

No, I just connected it to a car battery, just two bits of wire.

Interesting point, I will try and concoct something with a 5amp fuse and see what happens.

 

[Anthony1]

I would obtain some suitable diameter heat shrink tubing.

• Then place a 1 inch length of the heat shrink tube over each cable, away from the joint area.
• Then carefully solder the cables back together.
• Then try to fully encapsulate each of the soldered connections with a coating of two part epoxy resin to fully waterproof the connections. Make sure the epoxy goes past the cable insulation material. You may need to build up the coating in several attempts, allowing each coat to dry before applying the next.
• Then slide the heat shrink tubing over the epoxy once it has set and heat it up to shrink it into place.

I don't think heat shrink tubing alone will guarantee a waterproof joint.

Worst case scenario is that the connections aren't fully waterproofed and will corrode away over time and the fuse may blow if a current flows through the water between the two connections.
It is only low voltage, so no danger of electrocution, etc!.

Thank you.

I might look into that more closely.

 

[Anthony1]

All these tapes, epoxy etc that people are suggesting should make your morning cuppa taste interesting

It's alright we only use the fresh water tank for cleaning teeth and vegetables. Not together, I might add.

 

[Anthony1]

View attachment 125424

I've seen these. I may try one before I start welding etc.

 

[Anthony1]

Those waterproof connectors will only work well if the outer sheath of the clear tube containing the brown and blue cables is both circular and pretty rigid.

Looking at the photo, it appears as though the brown and blue wires are quite a loose fit inside the clear tube and that the tube is more oval shaped than circular.

The connectors rely on compressing a grommet around the circular outer cable to provide a working seal. If you do try to use them, then I would apply a silicon sealer on the ends, once fitted.

But as suggested above, probably worth replacing the pump now you have got so far.

You might be right. Re. replacing the pump.

 

[Anthony1]

Thank you to everyone for their ideas and senarios. All seem ok.

I might just bite the bullet and go for the new pump (longer wires) and put it down to experience.

 

[Kimbo]

Thank you to everyone for their ideas and senarios. All seem ok.

I might just bite the bullet and go for the new pump (longer wires) and put it down to experience.

Pleased to hear that, much better than food poisoning or a slow lingering death, after all what's forty quid when you own a Cali. ----------