FWC Raw vs. fresh water pump

[Qben]

As I understand it, FWC conversions use the existing raw water pump for fresh water and the new pump for raw water. Does anyone know the reasoning behind this? If the routing of hoses would work better, would I invite problems if I kept the existing pump for raw water and used the new one for fresh water?

Qben Oliver

[rigspelt]

Other way around: usually the original raw water pump just aft of the accessory drive remains for raw water, and the FW pump is added elsewhere, depending on the type of FWC system. At least, that's the setup on mine.

[Qben]

That reassures me somewhat. I was thinking it would be nice to be able to easily reattach the cooling system as it exists now if there were ever a failure in the fresh water system. Making as few departures as possible from the way it is now seems like a reasonable approach.

There must be a reason for both the Moyer and Indigo kits to convert the existing pump for use in the circulating loop though. Someone will probably know why.

Thanks for the input Rigspelt.

Qben Oliver

[jhwelch]

My fresh water pump is on the back of the engine. This makes for a very short and
neat hose run into the block, which is the only reason I can think of for having it
this way.

My salt water pump is mounted on a bracket on the stbd side of the engine and driven
by the fan belt. I've had a lot more troubles with the salt water pump (leaks from
failed bearings), so, at least for me, it is a good thing I can get to it easily.

-jonathan

[Qben]

Fan belt? You must have it set up as the Indigo kit describes. I can see how access problems would make it better that way for servicing purposes if one pump is more problematic than the other. Access shouldn't be a problem for me regardless of how it is setup.

Qben Oliver

[ndutton]

Using the original pump for fresh water you don't have to reroute any other engine plumbing other than the HX loop, it's ready to go as is.

[Triton106]

I don't want to steal this thread but I am curious if anyone has any experience with Indigo's Electrical FWC setup. They use a Johnson electrical pump as the antifreeze circulating pump instead of the mechanical pumpt.

I like the idea since it allows one to install the pump and the heat exchange behind the bulkhead under the cockpit. This alleviates the clutter in the engine room (for Pearson Triton the engine room is very cramped). No pulley, no additional belt, not muss no fuss. The pump's service life is over 1000 hours. Indigo sells the system for $550, not a bad price.

Here is the link:http://www.atomic4.com/fwcelect.html

[hanleyclifford]

here's another thought to confuse the issue a little more. when i converted to FWC, actually it should be described as 50/50 antifreeze cooling, i installed a BAITWELL pump from the Rule line most recently moving up to the 800 gph unit with removable cartridge. use an oil pressure cut out switch, of course. this is a fraction of the Indigo cost.

[ArtJ]

here's another thought to confuse the issue a little more. when i converted to FWC, actually it should be described as 50/50 antifreeze cooling, i installed a BAITWELL pump from the Rule line most recently moving up to the 800 gph unit with removable cartridge. use an oil pressure cut out switch, of course. this is a fraction of the Indigo cost.

The oil pressure switch should be involved with an electric fuel pump and
oil pressure, not engine cooling, fresh or salt. Please explain

Thanks

[hanleyclifford]

Art - i use oil pressure switches to control anything i do not want to continue running if the engine shuts down to include electric fuel pump, salt water pump, regulator power lead - even voltage sensing for the regulator which of course must be a completely independent circuit. i get al of this control out of two circuits the messiest of which i have combined into a thing i call the "ignition buss bar".

[David Masury]

My boat has a factory fresh water set up.. the fresh water is a closed loop using the pump on the engine circulating through a heat exchanger and tank.

The raw water is pulled through the heat exchanger by a second pump mounted over the starter and is driven by a pully off the fly wheel. A simple enough system.

I system runs a liitle on the cool side simple becaus ethe raw water pump pulls so much water it keep the coolant temperature in the holding tank around 140 degrees when running for a long time. I did measure the temperature in the head and that was around 180 degrees, so I don't worry about the engine running too cool.

David

[sastanley]

So, say I wanted to engineer my own FWC system using an electric pump? Where do I get the Heat Exchanger? I've done some research, but can't seem to find the model number of the HX typically used for the A-4.

[thatch]

Just to confuse the issue!

One of the benefits rarely talked about with a FWC system using 2 self primeing water pumps is that should one of the pumps fail you can normally make it home by simply re-routing the hoses and convert back to a RWC system. In the case of FWC systems using an electric circulating pump if the RWC fails this is not the case since they are designed to circulate not draw water. One other final thought, If you should decide to design your own electric pump /FWC system check the pump specs to make sure it is designed to opperate at the temperature it will be exposed to.
Tom

[Administrator]

So, say I wanted to engineer my own FWC system using an electric pump? Where do I get the Heat Exchanger? I've done some research, but can't seem to find the model number of the HX typically used for the A-4.

It's here in the online store.

Bill

[hanleyclifford]

FWC change over

I have not seen the Indigo electric pump except in pictures but I have to say that I have serious reservations about an electric pump handling hot anti freeze. I am very confident with the Moyer replacement pump handling the fresh (antifreeze) loop and I have had excellent results with the rule cartridge style pumps mounted right on top of a 1" thru hull handling the salt water side. I could mount a pump where the alternator used to be but I see no reason to do so. As I mentioned earlier I run my alternator up front using the Moyer PTO adapter and a double sheave.