Bilge water flowing back to bilge

[hd002e]

When the bilge pump kicks in, it pumps about a quart of water out and when it stops that water flows back into the bilge. The users manual does not recommend using a check valve but the re-flow is just enoughto trigger the sensor (fully automatic bilge pump) so the pump goes into a futile cycle (every 20 minutes or so).

Aside from cleaning out the remainder manually, how does one deal with this?

[Lost Horizons]

Install the check valve, or add a second pump with the check valve. Or use a wet vacuum cleaner.

[Dockhead]

Why God made maintenance pumps.


The answer to this age-old problem is to have a small pump with a check valve, or a diaphragm pump, with pickup mounted in the lowest possible place in the bilge.



Then a bigger pump WITHOUT CHECK VALVE, with a higher mounted pickup and float switch.


Each with its own discharge hose and outlet.

[Tetepare]

Bucket and sponge.

[jtsailjt]

Originally Posted by Dockhead

Why God made maintenance pumps.


The answer to this age-old problem is to have a small pump with a check valve, or a diaphragm pump, with pickup mounted in the lowest possible place in the bilge.



Then a bigger pump WITHOUT CHECK VALVE, with a higher mounted pickup and float switch.


Each with its own discharge hose and outlet.

I have a Whale Gusher pump mounted with a check valve close to the pickup and a remote float switch, located low in the bilge, and then a much bigger bilge pump with its own float switch mounted about a foot higher and this pump has no check valve. The Whale Gusher pump is a diaphragm type so pumps at a low rate so won't keep you from sinking if you have a significant leak, but they are quiet and very reliable and not prone to getting clogged so work well for pumping out incidental rain that comes down through the mast or slow leakage through your stuffing box, etc.

I'm assuming that DH had something similar in mind that he refers to as a "maintenance" pump but I've just never heard them called that?

[Recy]

Where is the water in the bilge coming from?

[gonesail]

Originally Posted by Recy

Where is the water in the bilge coming from?

exactly. bilge should not fill up in 20 minutes. also the hose running from the bilge pump may need to be shortened.

[Elie]

a small diaphragm pump manualy activated will dry the remaining water to dry the bilge as long as the pickup tube end is positionned at the lower part of the bilge

[Sea Q]

Best is a bilge well that is about 1 1/2 feet deep
Pump mounted at bottom
Float switch a foot above it
Float switch controlled by a timer
So the pump runs extra time after switch is in the off position .
There will still be drain back but not as much cycling.
I would be hesitant on a check valve could cause big time problems if it stuck closed

[SaltyMetals]

I used to have exactly the same prblm. The diaphram pump on my Jeanneau 43ds is about 2m from the bilge and about 1 m above it. Having pumped the bilge dry, and the pump then stopped, the water left in the pipe from the bilge up to the pump would slowly seep back down into the bilge and trigger the switch so it would run for about 10 secs every 20 mins.
So what is wrong w putting in a check valve in the bilge at the bottom of the pipe? Is this bec it might get blocked from debris in the bilge? My bilge has a fine metal screen about 20cm high (9") all around the top edge so nothing large ever gets into the bilge. There is not much room for yet another pipe in the bilge to which i could attach another pump.
My system has now been working perfectly since i put in the check valve 3 yrs ago.
Andrew

[bobfromcanada]

If it's taking 20 minutes for this to happen, and each time you pump out about a quart, them you are taking on water at about 3 quarts an hour. If it was just backflow from water in the hose, I would expect the cycle time to be much shorter, say a minute or two. And nothing else would come out when the pump kicks in, because that water would just fill the bilge pump hose. IMHO, you have a leak somewhere (fresh water system maybe).

[Captain Puget]

The pump can’t push above it’s level, it’s “head” ... or the height of hose above the pump.

Check valves are dangerous. I suggest a second pump that is vacuum or diaphragm based that is mounted above the waterline. Examples include - Arid Bilge systems and Dry Bilge. The first handles multiple zones, if needed, it is pricy.

[stormalong]

The problem with check valves with vane type pumps is that they may not be able to develop enough pressure to push the check valve open with the weight of the water above it.

I have a check valve and occasionally I have to reverse the flapper in it - it takes on a set after a few years. The lift (head) is about six feet. I also have a high water alarm about a foot above the bilge pump. It is a deep sump and can hold a lot of water before becoming dangerous.

A surprising amount of rain comes down inside the mast. Surprising because there are very few small openings for the rain to get in.

Both the pump and the check valve are original to the boat. Now 33 years old. Boat came with spares but have not used them yet.

[Dwsmith69]

I also have a 43DS which has the same annoying bilge pump cycling problem. Mine cycles every 2 minutes. The amount of time for the hose from high point to bilge to deposit its contents. This continues until I take a custom coat hanger reach down and hold the float switch until I hear the pump suck air. Winter time it will be months or when I defrost the fridge before this cycling begins. In the summer with AC running its a constant battle as the codensation on the AC lines drips into the bilge. There is not enough room in the sump to place pump. I considered check valve but was concerned flow rate restrictions in a emergency situation. There is a float switch on the market that you can program to run so many seconds beyond float switch activation but its now winter so it has fallen to the bottom of the list.

[Cheechako]

As Elie said: It's the water in the hose flowing back. Common. Many owners put a small lift style pump (not in the bilge, but with a hose that reaches down there) to take out that little bit. Raise the float switch on the big pump. Avoid check valves.