Bilge pump blues

[adamganz]

Somebody has to have figured this out. I have a rule bilge pump directly wired to the house battery - combo unit with pump and float switch integral. Two issues: first is that the pump now seems to struggle to get water from the depths of the bilge out of the boat - probably 3.5' vert distance to through hull. Second is that once the pump has pushed enough water out of the bilge to deactivate the float switch, the back flow retriggers the float switch. the thing recycles over and over until it blows a fuse or kills the battery, which is what I found this afternoon.

I've been racking my brain to figure out how to prevent this but am admitting defeat.

Any thoughts?

[mgphl52]

Add a one-way check valve between pump and discharge hose.

[tjr818]

Perhaps you could raise the bilge pump an inch or two although that would leave some water in the bilge, the pump would not run as often and the amount of water returning from the hose would not be enough to restart the pump. That is what we do aboard Slainte. The remaining water can be pumped out with the built-in hand pump.

[Steve Laume]

You have a few alternatives.

You could lower the pump or raise the switch. This will allow the pump to remove enough water so the back wash will not signal the switch to start again.

You could take the pump off of the battery, put it on a breaker and remove the float switch. This way you will control when the thing runs and will not have a dead battery if your boat ever develops a big enough leak to sink it.

You could install another smaller bilge pump to take out that last bit of water if you feel that boats need to be dusty dry inside a towel will be your last step in the dewatering process.

Check valves have a very dubious reputation in a bilge pump system. Even if it is properly functioning it will reduce flow. If it clogs it could disable the entire system. A vented loop would be the way to reduce the amount of back flow without compromising the outflow. It will also keep the system from siphoning the ocean back into your boat if the through hull is underwater when you pump the bilge. (I know this can and will happen, from personal experience. Well not the whole ocean but enough to scare the crap outta me.) To solve your problem, the high point and vented loop would need to be as close to the pump as possible. You want most of the water to head towards the through hull and only the amount that is in the hose, prior to the loop, would be returned to the pump.

Personally, I like the idea of a big pump on a dedicated breaker that I control. If you want to keep the auto switch, that will be a constant PIA, then it should be moved up if the pump is at the lowest point in the bilge. A vented loop would still be an extremely good idea if the discharge could ever end up underwater when the pump cycles. For quite a few years, Raven had only a manual diaphragm pump. I was and am very happy with it but also wanted some redundancy and a pump that I could put to work while I tried to problem solve a leak. Those auto switches were a great idea for wooden boats but I really don't see why they are still popular, Steve.

[Jim_B]

I solved this problem with a small 'sweeper' pump (with the integrated switch) and an inline backflow preventing valve.

Then mounted about 3 inches above the small pump is a rule 3700 (hooked to an alarm). The backflow valve will create friction and so is only used for the small boat leaks we all have. The big pump is in case something worse happens and the alarm will let me know about it.

I should add that the backflow valve is not trouble free. It has failed to seal a couple times in the last 5 years and will result in the perpetual recycling - but at a slower rate. I have a pump counter hooked to the sweeper so I can tell if this is occurring.

[jen1722terry]

We very much echo Steve L's comments on check valves and circuitry.

We have our pump on a 1/2" piece of starboard. We're going to change the float switch to a Waterwitch valve (no moving parts).

Lastly our manual pump inlet hose goes to the very floor of the bilge and we pump it a few stokes every week or so, which virtually eliminates the primary switch from running the pump.

Question: what size pup do you have? We use a Rule 3700 which doesn't seem to mind the 4-foot plus head it has to deal with.

Good luck

Jenn and Terry

[moctrams]

I have a Jabsco 37202 Bilge Pump mounted on a shelf in the port lazerette with a filter on the inlet and a hose dropped into the bilge.. I have a Water Witch secured to a piece of aluminum stock so I can take it out to clean it. This is my 2nd boat with this configuration and it is "dummy proof".

[mashenden]

A couple of thoughts...

While a check valve would solve most of the back flow issue, they are known to clog over time, which could have dire consequences. Personally, I'd rather have some back flow, but obviously the cycling issue needs to be addressed.

I would consider routing the hose in such a way as to make a U trap. Then the back flow is limited to what is south of the U trap. It means routing the hose above the level of the drain as close to the pump as possible.

Also based on your wording, it sounds like the pump used to do better and now is not as good. You may have some debris in the chamber or it may need to be rebuilt or replaced (I am not familiar with this specific model, but it looks to be a sound design).

Jabsco Hydro Air Bilge Switches are in use on my system - SO MUCH BETTER than any float switch I have tried in the past, which were prone to fail either from being in salt water for long periods of time or getting crud around them causing them to not float properly. Similarly to the aforementioned Water Witch switch, the switch never comes in contact with the water. They are a bit pricey but seem to offer maintenance free service (at least so far) as long as the pressure tube is properly secured in the bulge (since you already have a Water Witch this is probably not of interest but I figured others may benefit from the info)

[CD_Sailor]

... You could take the pump off of the battery, put it on a breaker and remove the float switch. This way you will control when the thing runs and will not have a dead battery if your boat ever develops a big enough leak to sink it ...

I echo Steve's suggestion. Despite their ubiquity, automatic float switches too often leave the vessel at risk. One would think that after this much time a solution would be available, but I don't think it is. Of course your circumstances (frequency of inspection, through hull arrangement, distance from mooring, etc.) may actually require some sort of automation.

My solution is four manual pumps (including a rather massive Edson 17) and a single switch-operated Rule 1000 for convenience.

[mashenden]

... You could take the pump off of the battery, put it on a breaker and remove the float switch. This way you will control when the thing runs and will not have a dead battery if your boat ever develops a big enough leak to sink it ...

I echo Steve's suggestion. Despite their ubiquity, automatic float switches too often leave the vessel at risk. One would think that after this much time a solution would be available, but I don't think it is. Of course your circumstances (frequency of inspection, through hull arrangement, distance from mooring, etc.) may actually require some sort of automation.

My solution is four manual pumps (including a rather massive Edson 17) and a single switch-operated Rule 1000 for convenience.

Not meaning to be argumentative, just surprised with these views. I could not sleep at night if I did not have an automatic bilge pump switch.

I have 2 - one controlling a pump and another that is set up higher that controls an alarm (and potentially another pump when time permits). I also have a gusher as a manual solution and a T with a valve on the motor's cooling intake that could also be used to help pull water out.

My concern is that I have a few fresh water leaks that can accumulate over time. One time I forgot to leave my primary pump on automatic, and had not returned to the boat after a few weeks in the spring (rainy). A neighbor called because he heard the secondary level alarm. I am sure it saved the motor and possibly the boat. As far as switches that are problematic, I feel that nut was cracked with the hydro switch or similar dry solution.

Presumably the differences in perspective relate to whether the boat is used/checked on regularly, and/or is connected to shore power. Mine is left at the dock connected to shore power most of the time, and sadly there are times when ia couple of weeks go by without me being there.

[mgphl52]

And a good solar panel can help prevent the dead battery issue...

[adamganz]

So there seems to be some difference of opinion on the value of an automatic bilge pump. The fact that that debate exists makes me feel better about my conviction that the current known options (at least known to me) may be lacking.

Going back to my original post and first couple of responses, I am not looking to have a completely dry bilge; I have low expectations here. I have enough water coming in that every 7 days I have a fairly full bilge, full enough that I worry when I'm not able to make it to the boat for more than a week. Leaving aside the fact that I should fix the source of the water, which I acknowledge would be a more direct solution, the solution I'd like would be an automatic bilge pump that kicks in when the bilge is quite full, and triggers off when the bilge is empty. A two sensor switch system. Does this exist? Should it?

As for the re-cycling issue I described, someone suggested locating the float switch well above the pump. If I understand this strategy, the idea is similar to the idea of locating a combined float switch and pump model higher in the bilge: that the water level higher in the bilge does not change as quickly as it does lower in the bilge where space is narrow/limited? Even so, I still think the back flow of water from the hose would trigger the switch, no?

All that aside, I do like the option of having the pump in the lazarette and a hose to the bilge.

[mgphl52]

If you have that much water coming in, I would suggest that you replace the packing pronto - or find out where else the water is coming from!

[mashenden]

... I have enough water coming in that every 7 days I have a fairly full bilge, full enough that I worry when I'm not able to make it to the boat for more than a week. Leaving aside the fact that I should fix the source of the water, which I acknowledge would be a more direct solution, the solution I'd like would be an automatic bilge pump that kicks in when the bilge is quite full, and triggers off when the bilge is empty. A two sensor switch system. Does this exist? Should it?

That is my scenario exactly. My leaks are probably not enough to sink the boat, but an automatic bilge pump is the ideal solution to reduce that risk to a reasonable level. I like the secondary level alarm to further reduce that risk.

You may be over thinking the switch part though (or I am missing your vision). Generally, all automatic switches (float switch, Water Witch switch, or hydro switch) essentially do as you describe. These switches close at a certain water level allowing electrical current to activate the pump, and then open the pump's electrical circuit when that level is reduced thus stopping the pump. Your problem appears to be that the back flow is causing the water to again rise to a level that reactivates the switch, turning the pump back on.

Having two switches would complicate the issue - just another possible point of failure.

If your system used to work fine, then an idea to consider is that your pump needs to be fixed or replaced. Your pump may have a built in flapper that used to stop water from back flowing that is worn out??

Next the solutions to consider would be either 1) to reduce the amount of back flow by making some form of U trap so less water flows back in, or 2) adjust your switch (Water Witch if I remember right) such that the existing amount of back flow does not cause it to kick back on. It is entirely possible that the latter suggestion will not work because the real problem is the back flow, but you could give it a try by either rotating the switch (assuming it has 2 senors like the one I envision) or raising the switch higher in the bilge to see if these changes affect the overall results. If this does not work, then I would go back to reducing the back flow.

I suggest tying a line around the hose so as to create a high point in it. Mine is tied up so that the hose is raised up to the level of my floor boards (near the pump), then goes back down and eventually goes up to the overboard outlet. This is a rudimentary U trap. Easy to try and may solve everything. But in your scenario, the pump is already up pretty high so just routing the hose coming out of the pump (toward overboard) so that it goes down a bit could effectively do the same.

All changes can be tested using a hose.

[mashenden]

More on the idea that it may be the pump is no longer working as well as it used to, causing more back flow.

I figured it had to have flaps or valves since it is a self priming pump. This picture confirms it. Part #11 is a set of two values.

http://www.pumpvendor.com/Jabsco_37202-0000_parts.html

I would take the pump apart and see if it has gunk in there causing the values to leak water back to the bilge - replace valves or pump if needed. Then reinstall and test. Less back flow should stop the cycling, allowing it to operate as envisioned.