Whale Supersub does not start moving water for a while.

[fergycool]

I've replaced my old bilge pumps with the two Whale Supersub smart pumps. Both sizes.

Both are fitted with NRV and recommended hose sizes.

The only criticism is that both pumps will not start moving water until water depth is higher than the strum boxes. This is way deeper than the 9mm thy say they will remove the water to. The pump appears to just spin. It just does not seem to be self priming until it is sucking from a lot of water.

I can cheat this by putting my finger over the "bleed ball" vent on top of the strum box.

Once the water starts to be "sucked" it will be drained to the stated depth.

Is this normal?

Ironically this means to "empty" my bilges I must first add a bucket or two to raise the level

Cheers
Chris

 

[Caer Urfa]

Hi Chris

I have a Whale Supersub 650 in my engine bay mounted on a 6mm thick ss base plate, I have found it will not start until the end nose cone is covered as that is what activates it.

I believe the spec says it will leave 10mm of water in the bilge, I have also found it needs a good clean a couple of times a year other wise a good bit of kit that I have had for a few years now

Mike

 

[fergycool]

Hi Mike. Thanks for your reply.

I was starting the pumps manually. They start, but do not start moving the water until the depth is about 30mm.

Cheers
Chris

 

[fergycool]

Thinking further this would fit the fact that the automatic switch at the other end of the pump is at least 30mm from the bottom.

 

[VicS]

Hi Mike. Thanks for your reply.

I was starting the pumps manually. They start, but do not start moving the water until the depth is about 30mm.

Cheers
Chris

Thinking further this would fit the fact that the automatic switch at the other end of the pump is at least 30mm from the bottom.

There does not seem to be any information on what type of pumps these are.

Presumably not flexible vane pumps , just simple impeller pumps which are not self priming. That would also explain why no spares such as replacement impellers are available.

Before they will pump they must be completely flooded. The switching of the automatic ones, when in automatic mode, does not occur until the water depth is sufficient for the pump to be flooded.

A non return valve and small pump volume ensures that there is minimal drain back when the pump stops.


These features make them particularly suitable for deep narrow bilges but less suitable I would think for the broad shallow bilges of a twin keeler.

 

[fergycool]

That's all plausible!

Back to the Pela for drying the bilges