Removed check valve from bilge pump- now it won't stop running

[MJH]

Originally Posted by sailor Martin

I have removed the check valve from the outlet of my bilge pump to prevent unnecessary resistance.

Now whenever the pump stops working, the water rushes back in and the pump kiks into action again. Eventually this will drain the battery.

Simplest solution please?

Already tried relocating the float switch- doesn't matter at all.

I'm thinking about installing the float switch slightly higher than usual and adding an element that will keep the pump running for an extra 10 seconds at least every time. Perhaps a special float switch with a delay on opening the circuit?

Cheers Martin

This is a common issue particularly with deep bilge boats. The problem generally revolves around the total vertical distance the water is lifted before expelled from the boat and the diameter of the hose...the larger and longer the hose the more water it will hold when the pump turns off and returns to the bilge. (You don't say the size pump or hose diameter and length you are using.) This is frustrating for those who demand a dry bilge and why many install a check valve which is not recommended by the experts because they can clog when you need them the most and run the battery down.

For starters it is best to have two bilge pumps, one large and one small. The smaller one will use a smaller diameter hose which will hold less water that returns to the bilge when it turns off. This should handle the minor everyday leaks. The larger pump is for greater amounts of water getting into the bilge that the small pump can't handle effectively. The larger pump should be located at a higher water level than the smaller pump.

My bilge is very deep and the water has to be lifted 6-7 feet to be expelled. I have a Rule 3700gpm pump plus float switch as my large pump with a 1.5" hose diameter without a check valve. My small pump is a Rule-Mate 1100gpm pump for the small everyday pumping with a check valve because even with only a 3/4 inch hose it still gets too much water returning and will cycle. Raising the pump to a higher level will only leave more water in the bilge. I use the 1100gpm pump because the smaller ones I have used have difficulty raising the water to that 6-7 foot level that I can't change.

That said, operationally the large pump is always ON, the smaller pump is not. But when I am at the boat I always use the smaller pump manually to empty the bilge and get it as dry as it can get due to the low level of that pump. Its not a perfect solution but gets the job done to my satisfaction.

Good luck.

~ ~ _/) ~ ~ MJH

[sinnerman]

The RULE / WHALE electric bilge pumps all have a rubber check valve ("joker-type" valve) installed directly on the outlet to prevent backflow.

It is not a traditional "check valve" in the sense, (i.e. pivoting flapper valve or sliding check valve with moving parts) but more of a "backflow preventer".

Without the rubber backflow valve, any water in the exhaust hose between the pump and the hose's high point "hump" (if there is one) will backflow through the pump back into the bilge whenever the pump stops.

The longer the exhaust hose run between the pump and the "top of the roller coaster hump", the more "standing water" in the hose.

My bilge exhausts through the transom. Last weekend we had a storm with strong winds blowing onto the stern, and the wind actually forced the hose standing water BACK into the bilge past the little rubber valve. So the valve is not very strong...

cheers

[Cadence]

Originally Posted by marshmat

That's precisely what the check valve is for. If you're worried about the (very slight) extra resistance of the check valve, then put it back in anyway, and replace the pump with one a size bigger.

[Clivevon]

Originally Posted by marshmat

The check valve should never be used to prevent water from coming back in from the outside. That's the siphon break's job. You can't rely on a check valve to do this; it's risky, unreliable, and would fail survey.

A check valve, if fitted, is just to stop what water is in the hose between the pump and the siphon break from coming back down into the bilge when the pump shuts off. They're used for this all the time, and I'm not sure what the concern would be in doing so.

Siphon break?? in a bilge pump hose? Thats a new one on me. Anyone else have those?

[zstine]

Originally Posted by Clivevon

Siphon break?? in a bilge pump hose? Thats a new one on me. Anyone else have those?

Anti-siphon loop and valve is recommended by ABYC and is installed by many (most?) manufacturers on bilge hoses. .. but that's not the OP issue of water in the hose.
instead of an antisiphon, another option is to plumb the bilge line, into the sink drain as high as possible. the sink works as a siphon valve.

not sure who posted about a P trap.. ridiculous! A P trap keeps sewer gas out of the house and is not needed/wanted on a gravity drain sink or bilge pump. now if you have a grey tank, then I can see a trap being used.

[RaymondR]

The problem is insufficient hysteresis in the switch. You can fix this by using two float valves and a latching relay or an electronic switch with adjustable hysteresis.

My auto bilge pump does the same thing but I have a manual bilge pump at the helm position which pumps the bilge really dry. Only problem is that the electric bilge pump is really quiet and sometimes cycles for a long time before I notice it's doing it. Been meaning to put a warning buzzer or light on it for a while now.

[rwidman]

Why is a check valve a bad idea in a bilge pump discharge?

Because the bilge pump is discharging "dirty water". Water that is often contaminated with debris such as leaves, pine needles, dirt and debris that falls into the bilge as you check the oil or work on things.

This debris can (and eventually will) get stuck in the check valve, either leaving it partially open and useless or blocking it closed with the result that the bilge pump will no longer empty the bilge.

A check valve is fine for potable water, but not for unfiltered water.

[BillKny]

For many years I worked designing chemical plants. Check valves were NEVER allowed as the solution to a problem that had any safety implications at all--EVER. There always had to be more robust solution even if it was more expensive or difficult.

I apply that same logic to MY boat. What you want to do on YOUR boat is your choice.

Bilgewater is quite likely to contain all manner of debris. Even if it does not normally do so, and you'd happily drink your bilgewater, in a flooding event all manner of stuff washes down. It's bad enough if it clogs the pump, but that is (or should be!) easy to pull out and clear. A wad of wet shredded paper stuffed into a check valve half way down the pipe will first be hard to troubleshoot in an emergency and second, tough to fix and get things working again.

The point is that a check valve is NEVER NEEDED. It is just a short cut to fix a problem caused by a bad design.

[captnknopf]

I do not know if anyone has bought a rule bilge pump recently but new ones come with check valves. If the float switch is mounted on an angle, it does not have enough hysteresis so turns back on too soon. Replacing it or remounting it so there is more water level between start and stop should help. Just raising the switch may do this as the bilge is probably wider a bit higher so the gallon in the hose will make the water rise less.

[Leee]

Wow. Loads of opinions, some even right. This is a good topic to help new boaters realize that they really need to sort out the wheat from the chaff when asking advice. Everyone wants to help so that's a great start and it is what makes these forum questions/answers interesting.

[SieveSailor]

+1 what mitiempo said.

[darylat8750]

I wrestled with this after testing a bilge pump (1 of 4 this one rather high in the aft end of the boat) that would not move any water. It turned out that the bronze check valve was frozen closed. Same problem with one in the middle of the boat. Lowest point in my trawler is about 1/3 from the bow. I re-placed hoses with smooth inners and made sure to have the anti siphon valves a suitable hight above the water line. The pump at the lowest point in the bilge is a whale gusher that almost vacuums out the last bit of water.

My theory is that any boat big enough to sleep on should have at least 2 bilge pumps. Might as well make the one that pumps the lowest point a diaphragm type.

[darylat8750]

I was helping a friend move his new 30 foot sailboat from Philadelphia to Florida. Motoring down the Chesapeake on a calm day I went below and stepped into water. The bilge pump was not working. After the excitement was over we figured out that the prop shaft was leaking a small amount. The through hull where the bilge pump emptied was aft and close enough to the waterline that when motoring with 0 heal the stern wave covered the hole. Since there was NO siphon break the bilge emptied and filled in a cycle until the bilge pump burned out. Poor design in a brand new boat.

[Panacea2183]

Originally Posted by sailor Martin

I have removed the check valve from the outlet of my bilge pump to prevent unnecessary resistance.

Now whenever the pump stops working, the water rushes back in and the pump kiks into action again. Eventually this will drain the battery.

Simplest solution please?

Already tried relocating the float switch- doesn't matter at all.

I'm thinking about installing the float switch slightly higher than usual and adding an element that will keep the pump running for an extra 10 seconds at least every time. Perhaps a special float switch with a delay on opening the circuit?

Cheers
Martin

Had the same problem constant cycling of pump
Install a high and low float switch with a relay
Additional advantage of taking “load” off of the float switch which fail often
My pump is in a sump which only hold about 3 cups of water. Rest of bilge is alway bone dry.

[CarlF]

Much worse than a check valve is to have only a single bilge pump.

I don't understand how people can work up such emotion about check valves when they are low on the list of bilge pump failure modes.

The most frequent are : clogging at the inlet, fouling of the tiny impeller, or failure of the float switch. All of which happen on pumps with or without a check valve.

As others mention, the fix is to have two bilge pumps. A daily "nuisance" pump with a 3/4" or even 1/2" hose. This small pump will fit lower and keep the bilge dryer. I prefer one with the built in a backflow preventer (aka check valve) to keep the bilge as dry as possible.

Then add the biggest 2nd pump you can fit (I use the Rule 3700) raised high enough that it (and more importantly the float switch) are normally dry and out of bilge water. It will last the life of the boat and hopefully never be used. This pump should be connected to a loud alarm.

As for switches. While the Waterwitch is more reliable than the miserable Rule, I have had one fail. They are very sensitive to any algae covering the sensor. The only one I've found to be completely reliable is the Ultra switch. Expensive but you only have to buy it once. https://www.go2marine.com/Ultra-Safe...waAngcEALw_wcB