Cooling Water Flow Alarms

Hi mate,

Funnily enough I was looking on the Dashew Cruising site last night.

SetSail FPB 83

Somewhere, in one of the engineroom photos, they had fitted a flow meter in the seawater cooling system. It was made by these people but I can't find which model it was.

Sight Flow Indicators | Sight Glass | Sight Windows | Flat Glass Gauge | Level Gauge | Digital Flow Meter | Liquid Level Gauges

Their Aussie dealer is ekotech.com.au

Hope this helps.

You don't necessarily need a full sized, full flow, device. If you use raw water to supply a shaft seal, there are small flow switches that will monitor that flow for example. A flow switch in the transmission cooler hose will do the same.

Or a pressure gauge will work as well.

That datasheet contains a lot of information. </sarcasm>

It has been mentioned here and in the first thread, a pressure switch or gauge somewhere behind the pump. That can be really easy if there are already threaded and capped holes in the coolant circuit. Which is most likely the case.
Remember that pressure is depending on engine rpm. The same is true for flow.

An option for wet exhausts is to install a temperature switch on the exhaust mixer. The idea is that if no water get injected the exhaust temperature will rise very quickly and thus trip the switch and sound the alarm before the engine has time to overheat. After all the thermal mass of the mixer is much smaller than the engine.

While you are running wires. Yet another way to prolong the life of the engine is to install a pyrometer. Measuring the exhaust temperature at the manifold and knowing the engine specs gives a good indication of the actual engine load. Again, not too complex if there is already a capped port.
A pyrometer as used on diesel engines is just a thermocouple with a remote gauge, so that is certainly not rocket science either.

Some wires, a piezo alarm buzzer and a simple temperature alarm sensor installed in the exhaust hose rigth behind the elbow will do. If your sea water flow in the cooling system goes down the amount of sea water for cooling the exhaust flow will go down and temperature will go up before the situation becomes critical for the engine.

...besides that there´s a simple cure for oxidation problems. Gold-plated terminals help a lot...

These go up to 3".

http://www.groco.net/SVC-MAN-07/Sec5/PDF/SSA-1G.pdf

Hi,

I would put it in the discharge line of the pump.

The sender counts the rate a magnet passes a sensor, pressure is irrelevant until it exceeds the structural limit of the device.

Again, use a smaller diameter unit and place it just before the spray ring or reduction gear cooler, anyplace where raw water flows will work.

Down stream of the pump. In fact I would look at putting it down stream of the engine if you can. That way if you develop a flow restriction in the engine you could catch it.

Hi,

Someone had a DD with this very issue here a few weeks ago.

True, but you would be aware that something is not good with the system.