Bilge pumps - set up help required

[wingdiver]

Hi
I have decided to fit a new bilge pump and have just bought a Rule 3700 Gold to do the job.
At present I have a massive manually operated pump (the diaphragm must be nearly a foot across!) and a Jabsco electric diaphragm pump, which is OK if more than a little low on capacity if there happened to be a real need - hence the new pump.
Both pumps are plumbed in separately and exit around the level of the waterline via seacocks.
I am adding the new pump rather than replacing the Jabsco as I can see no real need to get rid of it - and there room in the bilge 'sump' for everything. I am also adding a new switch to operate the new pump.

My questions are:

1. Should I plumb the new pump in completely independently of the other two or use one of the other sets of pipework?
2. If independently, any reason why the outlet shouldn't be above the waterline (I don't really want more holes under the waterline than is absolutely necessary)?
3. If I use an existing run, I assume I join up with the pipework after the existing pump rather than before, is that correct?
4. Which is the better of the two existing pump systems to join in with?
5. Would you join with a y-joint or an 'either/or' valve?
6. Would you put any one-way valves in the system?

Thanks in advance.
D

 

[fireball]

If you're adding additional pumps because the capacity of the existing ones are not be enough then I have a couple of points ...

1) Is your boat leaking that much that you need the capacity? If so - better to fix the leak rather than just empty out! I'll assume it isn't but had to ask!

2) You're probably looking for additional capacity in an emergency ... therefore apply Sods Law ... if it is going to go wrong it will - so by sharing the same pipework you're choking your additional pumping capacity and leaving yourself open to a failure there, rendering both pumps US.

I would run a completely separate system for the spare pump, if you really do not want another thru-hull fitting then perhaps T into the larger of the two pump outlets (on the inside of the stop valve) .. but do this as close to the end as possible.

I put a one-way valve in our pump, but it doesn't prevent the water returning in the end - so still have to sponge out that last little bit. More expensive valves will work better, but may also (like the cheapos) choke the output of the pump.

 

[lw395]

I think the Rule 3700 is a centrifugal pump, these must exhaust well above the waterline, otherwise they siphon back into the boat as soon as they stop!
also note that the water in the outlet pipework will tend to run back unless you fit a non return valve. This can be some litres of water!

 

[SolentPhill]

I agree with above but you may want to try a few options, You may have another outlet ie locker or something else you can put a Y joint in, if you cut into a current hose the water could be pumped out from one hose around and back in through the other B pump.

If you put another hole in the boat its ok but not best unless you need to.

Remember when you put the new B pump in to allow enough hose to put a bend ideally with a joint to bend it so you dont over bend the hose and shut it off. the hose must go higher than the water line or water will come back into your boat when its rocking.

I think its best to leave alone what the manufacturer did and find that other outlet hose, the pumps are powerful and can pump uphill without a problem.

Hope that helps Ive just done mine this way.

P

 

[pyrojames]

I ran my last (second) manual pump out through the transom about a foot above the water, with the pipe running up to the underside of the deck to stop following waves coming in.

I prefer to keep all pumps independant for redunancy, if one fails you ca simply move to the other. I also prefer for all bilge pumps to exit well abovet the water line, but still have seacocks.

 

[pete]

On my boat the pump outlets use the same skin fitting.
The main manual pump outlet rises up under the cockpit side deck and then down to the skin fitting which is about 4 inches above the static water line.
The electric pump outlet also rises under the cockpit side deck and joins the other hose with a Y fitting just before it exits the boat.
Pete

 

[MoodySabre]

On a Moody the bilge pump outlet is high up on the side at the rear and uses a plastic skin-fitting. No reason that I know for it to be low down, unless the pump is very weak.

 

[LadyInBed]

I would fit it as an independent system connected straight to the battery via a fuse and a float switch. Put a on /off switch across (in parallel with) the float switch so you can over ride the float switch.
The exit should be well above water level within the bounds of the pumps header spec and NO seacocks in the line.
This way you can leave it on when you leave the boat - better a flat battery than a waterlogged boat!

 

[MikeBz]

Can someone point me at a source of non-return valves suitable for an electric bilge pump installation?

Mike

 

[wingdiver]

Thanks for all the useful comments. Will give all comments careful coinsideration before I start as I want this to be right.
Oh and MikeBz, you could try here Jabsco bilge pump accessories
Cheers
D
PS post number 100 - wahay! /forums/images/graemlins/smirk.gif

 

[robbieg]

You might want to consider whether a one way valve will restrict the flow from your pump & the amount of head you build into the system if you are looking for your rule 3700 to shift as much water as possible in an emergency-the pumps are sensitive to both & your expected galls per hour can be drastically reduced by both factors. May also want to consider the wiring to ensure its up to the job-voltage drop etc.