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Shower pump out

Our boat shower has the sump and bilge pump arrangement. We had to replace the whole unit about 5 years ago due to failure of the automatic float switch. The new design has a float switch integral to the pump and we are now on our third sump pump due to unreliability of the switches. We do keep the filter in place and clean the sump as required. We are considering changing to Whale Gulper type pump. Are these pumps reliable? Are they happy running the whole time we are showering as we are not in feet-in-dirty-water school of showering? Our wash basin empties through the sump. Is it possible to plumb the pump dishwasher style so the wash basin empties by gravity without the need for an extra skin fitting?

Asked by: Clive Dutson  | 12.01pm, Wednesday 31 July

WW says:

The reliability of the bilge pump and sump arrangement for emptying a shower doesn't seem to work that well long-term in many narrowboats, as you have found out to your cost.
The Whale Gulper pump is a diaphragm pump, using a single large diaphram. They can run dry with no problems at all (with no time limit) and are quite capable of shifting solid and semi-solid waste (they can be used as toilet holding tank discharge pumps- so showers are a doddle to cope with!)
You would have no problem running the pump while you were showering, and it would quickly remove the water- though I have to say they are not the quietest of pumps, they are very reliable. If they do block, then they are easy to clean out and can be repaired, so tend to be very long lasting.
It is unusual to run the sink into a shower sump these days, for many of the reasons you have found. It would be far better to fit the sink to drain directly to the skin fitting, as you suggest, then plumb in the shower drain "dishwasher style". However, ideally make a loop in the shower drain hose that is higher than the overflow of the sink, so that when you drain the sink, it does not flow backwards into the shower (which is a distinct possibility).
Also, make the length of the hose between the shower and pump twice the length of the hose from pump to skin fitting. This will mean that when you turn off the pump, you will not end up with any of the grey water remaining in the pump-to-skin fitting hose backfilling into the shower tray.
Let us know if we can be of any further help.

Mark Langley  | 1.39PM, Wednesday 31 July

Pump it until its dry is the easiest way: as long as there is air in the system (i.e. not full of water) it is unlikely to be damaged, as the diaphragm will absorb any increase in volume if a water-air mixture is present. Gulpers do tend to flush themselves out quite well!
You could detach the hoses at each end and ensure it is drained fully, though I rarely have done this on any boat I have worked on or owned.
If you want to be safe, in a very very cold winter, you could mix a small amount of non-toxic food safe antifreeze (like "Freeze-Ban" and pour this into the system and pump it through. A bottle would probably last many years, as very little (around 100ml of solution) would be required.

Mark Langley  | 2.38PM, Wednesday 31 July

Readers say:

Thanks for this. I forgot to ask a further point: how do you winterize the gulper? The sump is quick job with the wet and dry vac.

Clive Dutson  | 2.03PM, Wednesday 31 July

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