How to connect two bilge pumps

[FOuR BuOYS]

I have two bilge pumps(500gph each). One is at the very back of my bilge under the motor and the other is in front of my motor. The float switch is about half way between. The wiring is no problem, I have figured that out.

I am just not sure if I should connect the outputs from both pumps into a common throughhole. The connections would be made close to the throughhole. Or should the connection be made on the floor. Or should I have a throughhote for each pump?? Installing a second throoughhole is a way bigger job.

Thanks

 

[tswiczko]

Re: How to connect two bilge pumps

Separate discharge lines separate through holes.

It could be done as one line but would be prone to failure. On your bilge system adding a failure point is not a good idea and not providing any redundancies to the system

BTW how are you wiring them?
Are they both to run off the same float switch or separate switches?
If you are running them off one switch, is that switch rated for 2 pumps?
is there a manual way to run the pumps if the float switch fails?
Will the float switches bring the system on even if the console switch is in the off position?

I would go as far as separate float switches, seperate manual switches and seperate circuits in addition to the seperate discharges.
This would create two independent bilge system with equal capacity for redundancy and in the event of emergency could be run at the same time for double capacity

 

[Don S]

Re: How to connect two bilge pumps

Treat them as two separate pumps. Both electrically, and discharge hose.
Then, if one fails, the other doesn't go with it.

 

[UncleWillie]

Re: How to connect two bilge pumps

You can do it any way described, but you need to make an informed decision.

Plumbing them both together will reduce the amount of flow as opposed to plumbing individually.

If one pump fails the other pump will pump most of its water backward through the failed pump.
You won't get 50% flow, your will get 5% flow!

Wiring them together means that if one thing goes wrong electrically, both pumps go dead.

The reason for having two pumps is for redundancy.
Each pump should be totally separate all the way back to separate batteries.

 

[sccatfish]

Re: How to connect two bilge pumps

I probably wouldn't run both through a 3/4" line but I might would run both through a 1-1/8" line or bigger. Plus you'd probably want to put check valves on there so if one is running and the other isn't you aren't just recirculating the water and not pumping it out, but check valves reduce flow. Best option is just to put in a separate thru-hull. It's not that hard just use the appropriate sized hole saw and seal both sides with 5200. Hardest part will probably be gaining access to the spot on the inside and making sure it's in a spot that is out of the way and where you won't drill into something else.