I feel a switch is important - it needs only be a simple on/off switch in
parallel with the float switch.

I believe that is what I said. At any rate I agree and that is exactly how
I have mine wired. It is the three way switch that allows you to turn the
pump completely off so even the auto doesn't work that I object to.


"David Flew" wrote in message
...
I apologise in advance for the following rant .....

I feel a switch is important - it needs only be a simple on/off switch in
parallel with the float switch. It lets you test run the pump without
lifting the floors. My boat runs with quite a lot of water in the
bilges - rainwater and sal****er washdown. So whenever I visit for a
quick check I can test run the pump and be sure it's delivering at full
flow. And that the fuse has not blown. It also lets me remove water
below the "cut-out" level for the float switch - useful if I'm doing a big
wash-down and want to keep the water flowing to the pump. Only issue is
if I should leave the switch on and run the battery flat, but the pump is
noisy. You could use a momentary contact switch, but if you NEED the
pump, you probably can't be there holding the switch. The second pump
does not have a float, just a switch. It's connected to the engine
battery, and is thus isolated unless I'm on the boat.

My boat does not heel, and I'm not a lover of check valves. They come
second on my list of things which fail after pressure switches ...... but
that's my industrial experience showing, why should I think that boats
will be better ???

I made one discovery soon after buying the boat which was a bit scary.
Both bilge pump discharge pipes ( 1") were plumbed direct to through-hulls
about 5" above the water line. This boat is unattended for up to a couple
of weeks. It was making perhaps 1/4 " per day, plus rainfall. And the
bilges had a lot of "stuff" in them - old fishing line, wood shavings,
cockle shells. No solar cell back then. It would not have taken much
"stuff" to either jam the pump and blow the fuse, or clag up the impellor
and increase the running time on the pump ... and flatten the battery.
Only happened a few time before I fitted the second battery. It would
not have taken much for the boat to take a lot more water - it's 40 years
old. Loss of one nail is more than enough to made it 1" per day.

5" of extra water in the bilges is not in itself a disaster - it's over
the floorboards, but not into engine or electrics. .
But as I purchased it, 5" was enough to take the bilge pump outlets
under - and then there would be two x 1" holes in the boat. Hours and
it's down .....

I've since re-routed the hoses so that they are looped much higher. With
no check valve, they drain back once the pump stops, so there is no
siphon.

And before anyone asks, the previous owner visited the boat every second
day, so this was not an issue for him.

I hope the above will help someone else eliminate some of the things which
can go wrong - at least some of those I've found.
David



"johnhh" wrote in message
...
Many of us think the on/of/auto switch is a bad idea. It is far to easy
to turn it off unintentionally. My preference is just on/auto. Fuse it,
not circuit breaker which is too easy to turn off. It should bypass the
then main DC house switch. If you need to turn it off to work on it,
pull the fuse, but make damn sure you put it back and test it.


"Graham Frankland" gfranklandattiscalidotcodotuk wrote in message
...
wrote in message
oups.com...
I have a manual bilge pump in a Newport 27, and
would like to add an automatic electric one.

What is the easiest way to do this? Can I use
(at least some) of the hoses that the mechanical
membrane pump uses?

The membrane pump is mounted in the back of the
cockpit.

Can I put both pumps on the same hose, i.e. can I pull
water through an electric (rule) pump when using the
manual, and can I push water through the membrane
pump with the rule?

If not, what is the next best/simplest setup?

Thanks for help and suggestions,

They can physically be plumbed in line but it's a bad idea as it
drastically restricts the flow and, more important, one problem could
affect both pumps, leaving you unable to pump out.

Although there are some electric pumps with integral auto switches I
always prefer separate simple float switches wired through a dedicated
on/off/auto switch, connected directly (via a fuse but not through the
isolator) to a domestic battery. Although it slightly restricts flow
rate, I always fit a non-return valve in the outlet to the skin fitting
to avoid any chance of back feed when heeled.

Graham.

"David Flew" wrote

I feel a switch is important - it needs only be a simple on/off
switch in
parallel with the float switch. It lets you test run the pump
without lifting the floors.

Convenient but, like a lot of conveniences, not necessarily a good
idea simply because it is convenient. You ought to be lifting the
floors to access water level, look for debris jamming the float
switches and pumps, verifying that the pump is actually moving water
and not just making a whirring noise. As long as you are down there,
you might as well use the handy float switch. This is a prime failure
point itself so verifying function is a good idea.

A manual switch in parallel with the float would be a good back up to
float switch failure but I would put it under the floor boards for
these same reasons. As long as it is there, why not make it a float
switch as well? Then, if the water gets that high because of low
switch failure, the pump will go on. This solves the problem of
difficult access to the low switch.

A nice thing about my circuit

http://home.maine.rr.com/rlma/Bilge.htm

is that just flipping the high switch momentarily runs the system all
the way down so I don't have to hold the switch up the whole time. I
know this is a more complicated system than most people want to bother
with but it was fun to put together and works great.

--

Roger Long

"johnhh" wrote in message
. ..
I feel a switch is important - it needs only be a simple on/off switch in
parallel with the float switch.

I believe that is what I said. At any rate I agree and that is exactly
how I have mine wired. It is the three way switch that allows you to turn
the pump completely off so even the auto doesn't work that I object to.

If people are so dumb as to leave it switched off then perhaps they
shouldn't have a boat anyway.

I aint't even gonna go there. I suggest you read "The Design of Everyday
Things" by Donnald Norman and get back to me.


"Graham Frankland" gfranklandattiscalidotcodotuk wrote in message
...
"johnhh" wrote in message
. ..
I feel a switch is important - it needs only be a simple on/off switch
in parallel with the float switch.

I believe that is what I said. At any rate I agree and that is exactly
how I have mine wired. It is the three way switch that allows you to
turn the pump completely off so even the auto doesn't work that I object
to.

If people are so dumb as to leave it switched off then perhaps they
shouldn't have a boat anyway.

On Thu, 26 Jan 2006 12:22:02 +1100, "David Flew"
wrote:


Not a bad idea to have a 'basket' over the pumps and float switch.
Also two pumps running off one float switch gives some redundancy.

IMHO the best way to go is a float switch and two small pumps, then
higher up above normal bilge water levels another float switch and
much larger pump. Ideally run each off different batteries.

cheers,
Pete.

I agree about the basket, if you have enough space. I don't, and mesh which
is small enough to protect the pump from debris soon blocks up with gunge.

A strainer over the pump and switch made of 5mm sq stainless mesh
should do (I have a bird feeder made from the stuff)

The Johnson float switch has an in-build strainer, so it's OK, and I just
have to regularly flush the bilges and be careful about housekeeping when
I'm doing carpentry on board ...

I've doubts that having two pumps off the one float switch makes things more
reliable. If either jambs, it would blow the fuse .... If you have
separate fuses for the two pumps, you still need a larger common fuse to
protect the switch and wiring.

I'd have two fused lines each feeding one pump +ve, then the -ves from
the pumps connected together and going to the float switch and back to
battery -ve. The on/auto switch would just go in parallel with the
float switch.

Also it seems the 1000 gph pumps seem to use the same casing as a
500gph pump, but cost almost twice as much. So for the price of some
extra hose and an extra outlet you can have 2 500gph pumps instead of
a single 1000gph one.

IME the pumps themselves fail in other ways rather than just jamming,
on my previous one the shaft snapped. So in that case 2 pumps would be
much better than one. Even if one gets partially blocked, the other
will work and lessen the rate the battery is flattened.

Maybe a straw poll of bilge pump/float switch failures would be
useful, can anyone else comment?

cheers,
Pete.

David

wrote:

I have a manual bilge pump in a Newport 27, and
would like to add an automatic electric one.

What is the easiest way to do this? Can I use
(at least some) of the hoses that the mechanical
mount a "T" piece to the output and connect the two pumps there so that
they work pararll to one another ,ensure that the electrical pump has a
non-return valve
membrane pump uses?

The membrane pump is mounted in the back of the
cockpit.

Can I put both pumps on the same hose, i.e. can I pull
water through an electric (rule) pump when using the
manual, and can I push water through the membrane
pump with the rule?

If not, what is the next best/simplest setup?

Thanks for help and suggestions,

Chris