Hunter 34 Bilge Pump Issue

[Steve Olson]

I woke up to hear my bilge pump running. I inspected the bilge to find enough water inside to properly activate the bilge pump and the pump was spinning, but not pumping water out of the bilge. I disconnected the exit tube from the pump and found that the pump appeared to be working properly and was pumping water with what seems to be a sufficient amount of force, so I suspected the exit line or through hull was blocked, so I took my garden hose and, from inside, was able to get the hose water to exit the boat quite easily.

This is not making sense to me. If the bilge pump is pumping out water with force and then I'm able to get water from the garden hose to force water through the exit tube and out of the boat, how is the pump not able to pump the bilge water out?

Boat: Hunter 34. Bilge pump: Rule 1500.

 

[Snotter]

Do you have a one-way valve in the discharge line?

 

[Ralph Johnstone]

Starting at the beginning, do you see bilge water exiting the thru hull ?

As Snotter has mentioned, it's quite common to see the bilge repeatedly re-filling if the check valve has failed.

 

[Steve Olson]

Starting at the beginning, do you see bilge water exiting the thru hull ?

As Snotter has mentioned, it's quite common to see the bilge repeatedly re-filling if the check valve has failed.

Hum…where is the check valve located?

 

[Steve Olson]

The water doesn't exit the through hull except for when I took my garden hose and hooked it directly up to the hose that leads to it. In other words, water doesn't exit with the pump, but it does with the garden hose, which is odd, as the pump seems to me pumping water strongly.

 

[Steve Olson]

The water doesn't exit the through hull except for when I took my garden hose and hooked it directly up to the hose that leads to it. In other words, water doesn't exit with the pump, but it does with the garden hose, which is odd, as the pump seems to me pumping water strongly.

Figured it out…my battery bank was low and not providing adequate power to my pump!! Durrrr…new to boat ownership here, but I'm learning!!

 

[Ralph Johnstone]

The water doesn't exit the through hull except for when I took my garden hose and hooked it directly up to the hose that leads to it. In other words, water doesn't exit with the pump, but it does with the garden hose, which is odd, as the pump seems to me pumping water strongly.

Uh oh, time to get technical here.

The way to get a rough idea as to what the pump is doing is to first attach a piece of clear tubing to the discharge of the pump. Doesn't matter how small the diameter is. Make it reasonably water tight using duct tape.

Run the tubing overhead, at least 10 feet in elevation and then see how high the pump will push the water. This will show you the static (non flowing) pressure of the pump. The height of water should be well over the level of the thru-hull.

The attached chart will give you an idea of what kind of flow rate you can expect depending on the pressure (created by the friction of your hose plus the height of the thru-hull above the pump) delivered by the pump.

If the pump checks out, a little holy water may be in order .

 

[Benny17441]

I was going to say if you were using the hose from the inside to the outside that even if you had a check valve the water would have flowed. It was pretty obvious the pump did not have enough power to lift the water the few heads to the outlet. You have found the cause as low voltage and that will do it. Determine why and how low the batteries were and check for an undue voltage drop in the wiring to the pump.

 

[Allan12210]

Also check your wiring. If original like mine was a number of years ago, it is pure copper and wiil become corroded. I replaced mine wit tin plated copper wire. I also upgraded to the 2000 gph pump just because it could push that much harder.

 

[Irish Cream]

Had the same issue with our 34......Found that when the bilge water dropped below the pump intakes, an air bubble developed in the pump and the pump lost prime.
Our solution was to keep water in the bilge to cover the pump intakes and routinely flush the bilge with a fresh water/bleach solution to keep the bilge smelling fresh.
Note: as with he other posts, we had a clear discharge line between the pump and the check valve.

 

[John T1594]

Air Lock

If you use a check valve, keep the valve close to the pump with a short run (less than ~ 6") of clear hose. A longer hose is subject to an air lock which will cause the pump to run but not pump any water.

 

[Dan Johnson]

H34 bilge sump pump line check valve...

If you look carefully (it helps to assume a bat-like position) at where the hose from the bilge sump pump passes through the starboard fore/aft stringer, you might find a check valve on the outer side of the stringer, just where you can't get at it unless you remove the water heater, and, in my case, the A/C unit as well. Backflow is a sure sign that it's not working.