Cummins QSC “low seawater flow” alarm

[jeff vargas]

Cummins QSC “low seawater flow” alarm came up today for the Port engine. Cleaned strainer, plenty of flow into strainer, Impellers only have about 80 hours on them, plenty of water coming out exhaust. Ran boat and it doesn’t get above 165 degrees and runs at the same temp as Starboard engine. So, I’m guessing it’s the sensor. Also, I can’t clear the alarm from the SmartCraft. It let me clear it a couple of times as I started and stopped the engine a few times and it cleared but now it just stays on. I’m guessing a bad sensor or wire connection.

Any ideas? Can someone point me to the location of the sensor? Is there in fact a sensor? Thank you in advance!

Topic

[Tony Athens]

Wet riser

Totally “Doomed to Failure”.

I did not catch that on his 1st post.

Tony..

[Rob Schepis]

Jeff,

Yup, right in your first post you noted it would likely be a sensor or connection, good instincts are a wonderful tool!

I don’t like the looks of the jacketed wet exhaust elbow in your followup pic. Have any overall shots of your exhaust you can share? Is this your setup?

[jeff vargas]

Makes total sense! My first inclination it was a sensor was that it “alarmed” immediately after starting the engine and there was plenty of water flow. Just had to find the dang thing.

[Tony Athens]

Cummins Seawater Water Flow alarm

Well there it is–Cummins ( Mercury Smartcraft actually) offered a seawater flow alarm for the engines as as option.

I’ve been calling these “the most impost alarm” you have have on an engine that has a wet exhaust for a couple of decades.

In truth, this is a heat sensing switch that makes contact between the two wires when the heat on the surface of the exhaust mixer rises to a set point ( say 180F -ish.). No or very low seawater flow cooling the mixer=big temp rise=sets off the “seawater flow alarm”.

Been including these on 90% of our exhaust system for over 25 yrs.Many generator companies use them as one of their base alarms which is where I probably got the idea from..

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jeff vargas

[jeff vargas]

Follow up with pics

So I figured this out and this may be specific to my 48 Sea Ray Sundancer exhaust mixing elbow. There’s a sensor on the mixing elbow. While I was working to replace my sanitation hoses, I must have knocked something loose on the sensor. I removed the wire connectors, cleaned them and alarm disappeared. I just wanted to follow up in case anyone ever comes across this alarm.

[David Amble]

This post got me thinking…..

Whilst I have QSC600 engines driving Zeus drives, there are sensors fitted to the exhaust just after the ‘shower’. I attach a photo which may help. I have never had this alarm come up on any of my engines so not sure what would be displayed in the Vessel View. I did look through the code lists for ISL/ISC and the closest seems to be 1717 and/or 2346b, which may have been retagged from the truck engines. I also had a look at some QSC installation drawings and they show a ‘sea water flow switch input’ as part of the engine harness.
David.

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jeff vargas

[Tony Athens]

SmartCraft seawater flow alarm ??’s

Post a good picture of the display showing the alarm……………….

To be honest, I am not even sure what SmartCraft has for a seawater flow alarm, but Corey or I will take a peek.

I have kinda put Mercury electronic out of my mind. Cummins has too as they can’t seem to support it either.

Tony

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jeff vargas

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