Water flow alarm, needed?

Firefly has only the engine temperature gauge and buzzer. I have a Ford Sabre 120 and as this is the same base engine as the Lehman 120 marinized by Sabre, it must have the same cooling weakness inherent to the Ford Dorset as the Lehman.

I am considering adding a raw water flow and wet exhaust warning system to monitor both the raw water flow into the engine an the water flow through the exhaust for cooling.

This is the system I am thinking about...

20358 Water Flow and Exhaust Panel, 12v [] - $46.00 : AQUALARM, Warning Systems For Land And Sea


Does anyone else have this system and how is it?
What does your boat have in the way of water flow indicators?
Overkill, unnecessary, waste of money?
Thoughts, ideas, comments?

Thanks in advance for your input.

Greetings,
Mr. F. Isn't this unit performing the same task as an exhaust temperature sensor? 20245 Exhaust Alarm Kit. Single Engine [] - $73.00 : AQUALARM, Warning Systems For Land And Sea
I wonder which "system" would give you the best (quickest) response? It seems the unit I cited has fewer moving parts and might be less prone to gumming/jamming up and require less servicing. A more passive system if you will. Good question.

I think its worth it for $46.

We have an older Aqualarm Five System Monitoring Kit. I've never had the exhaust temperature go off but we did lose our water flow and the sensor did it's job. We shut the engine down immediately. The response was quick enough that we did not damage the impellor. All our sensors are tied to a bell that gets your attention on or off the boat. I think they are a good idea.

There are other good systems out there. Maybe someone can suggest an other manufacturer.

20001 Five Systems Monitoring Kit Single [] - $349.00 : AQUALARM, Warning Systems For Land And Sea

RT Firefly said:

Greetings,
Mr. F. Isn't this unit performing the same task as an exhaust temperature sensor? 20245 Exhaust Alarm Kit. Single Engine [] - $73.00 : AQUALARM, Warning Systems For Land And Sea
I wonder which "system" would give you the best (quickest) response? It seems the unit I cited has fewer moving parts and might be less prone to gumming/jamming up and require less servicing. A more passive system if you will. Good question.

Click to expand...

Thanks for the response, the kit I am looking at has the exhaust input (I will need to add the sensor band) for overheating exhaust. It also has the raw water inflow warning (I will also need the flow-sensor inline with the flow from the strainer to the impeller) to show a lack of water into the engine.



My thoughts are if I start up with a closed sea-valve or if weeds or a plastic bag block the water flow the alarm will go off even before there is time for a temperature increase anywhere in the engine. Seem right?

The exhaust temperature may just be belts and suspenders.

It seem the entire setup can be in my hand for a bit under $200.

What am I missing?

I don't think your missing anything but for a $150 more you could add low oil pressure, fire and high bilge. Just an idea.

Larry M said:

I don't think your missing anything but for a $150 more you could add low oil pressure, fire and high bilge. Just an idea.

Click to expand...

Interesting!

You gave me a thought, if the panel is just an indicator light and alarm responding to a closed circuit.

I could substitute other items for say the high water (I already have) and say the fire (Fireboy system with indicator on board).

I would like a exhaust temp. sensor and water flow on the gen-set and perhaps with a relabeling of these two items and the purchase of a flow sensor and exhaust temp sensor for the gen-set I could have both covered on one panel.

Hmmm Thanks for the food for thought.

Yes, you want both water flow and exhaust temp sensors. You can have flow, but still be in an overheat situation for a variety of reasons. Some folks think the Borel exhaust temp sensor is the best, but I've had good luck with most Aqualarm products (except their bilge pump switch). Defender has the Aqualarm on sale right now:

Marine Engine Overheat Detectors on Sale

If you want to go deluxe, add a pyrometer gauge to get a baseline and detect emerging issues before they hit the alarm stage:

http://www.sbmar.com/smx-marine-pyro-egt-gauge-kit.php

I have the twin engine six systems Aqualarm. Very good system. Much more trustworthy than volvo penta panel alarms.

SCOTTEDAVIS said:

Interesting!

You gave me a thought, if the panel is just an indicator light and alarm responding to a closed circuit.

I could substitute other items for say the high water (I already have) and say the fire (Fireboy system with indicator on board).

I would like a exhaust temp. sensor and water flow on the gen-set and perhaps with a relabeling of these two items and the purchase of a flow sensor and exhaust temp sensor for the gen-set I could have both covered on one panel.

Hmmm Thanks for the food for thought.

Click to expand...

Just be aware that some of the circuits alarm when broken and some alarm when made.

I have an old Aqualarm sensor w/ a beeper from RadioShack on my downeast boat back from 20 years ago when they only offered one size, 1-1/2NPT. It has worked well all those years and has saved me several times.
Install it in the discharge line into the exhaust, that way it warns of a blown-off engine hose as well as ceased water flow.
That said, I installed a newer 1" one on Island Seeker and it failed in short order. My son installed the same thing on his boat and it failed too, blocking flow to one of his manifolds causing other damage.
Now I see they have abandoned that style. I hope the latest ones are better.

obthomas said:

Just be aware that some of the circuits alarm when broken and some alarm when made.

Click to expand...

{Yes Dear, that alarm means everything is fine, when it stops we have a problem.....what!.... say again!...huhh?.... why are you packing your duffel? }

obthomas said:

Just be aware that some of the circuits alarm when broken and some alarm when made.

Click to expand...

Which ones alarm when broken? I'm pretty sure that on the Aqualarm systems, all circuits alarm when made.

On my Hatteras the engine temp alarm was a "normally closed" sender, meaning it alarmed when open.

caltexflanc said:

On my Hatteras the engine temp alarm was a "normally closed" sender, meaning it alarmed when open.

Click to expand...

I think that wouldn't work with the Aqualarm panel then.

The Aqualarm water flow and oil pressure switches are normally closed, but "normally" means when there is no flow / no pressure. (So those circuits should only be energized when the engine is running.)

QB said:

Which ones alarm when broken? I'm pretty sure that on the Aqualarm systems, all circuits alarm when made.

Click to expand...

On my aqualarm system the bell sounds with ignition on because the oil and water switches are closed (made). They open when water flows and oil pressure builds to silence the alarm. My temperature switches provide a ground (make) when overheated. The fire alarm shorts as does the high water alarm (makes) so you are right. I stand corrected.

QB said:

I think that wouldn't work with the Aqualarm panel then.

The Aqualarm water flow and oil pressure switches are normally closed, but "normally" means when there is no flow / no pressure. (So those circuits should only be energized when the engine is running.)

Click to expand...

Yes, the Hatteras has a proprietary panel of relays. Though I am pretty sure Aqualarm has a replacement for that too. If you have any questions, contact them, they very helpful.

My theory was to go straight for the "potential overheat" symptom... so replaced our original analog water (coolant) temperature gauges with digital gauges that have built-in programmable alarms.


Our normal engine ranges should be between 160-181°F, over 200°F would be worrying... so I set the alarms for 185°F... on the theory that would get my attention and I could begin troubleshooting (including shutdown) right away.


-Chris

ranger42c said:

My theory was to go straight for the "potential overheat" symptom... so replaced our original analog water (coolant) temperature gauges with digital gauges that have built-in programmable alarms.


Our normal engine ranges should be between 160-181°F, over 200°F would be worrying... so I set the alarms for 185°F... on the theory that would get my attention and I could begin troubleshooting (including shutdown) right away.


-Chris

Click to expand...

Chris, do you have a source for those digital temp indicators.

Saw these on a guy's boat, he says they're pretty slick. Looked cool.

EGT Digital PMDW Series Pyrometer Gauge + Probe Kit - Marine Engines

You can purchase a thermal switch disk in any temp range for $10 and hold it on the exhaust elbow with a hose clamp then wire it into your existing alarm system.

Larry M said:

We have an older Aqualarm Five System Monitoring Kit. I've never had the exhaust temperature go off but we did lose our water flow and the sensor did it's job. We shut the engine down immediately. The response was quick enough that we did not damage the impellor. All our sensors are tied to a bell that gets your attention on or off the boat. I think they are a good idea.

There are other good systems out there. Maybe someone can suggest an other manufacturer.

20001 Five Systems Monitoring Kit Single [] - $349.00 : AQUALARM, Warning Systems For Land And Sea

Click to expand...

I am surprised the exhaust temp alarm didn't go off. You must have been quick on the shut down!

I've been thinking of installing an alarm system. Aqualarm make good ones and they've been doing it for more than thirty years.

Yes they do make some sensors in both normally open and normally closed versions. I think Bertram as well as Hatteras used the normally closed system.

Arcticspud said:

I am surprised the exhaust temp alarm didn't go off. You must have been quick on the shut down!

Click to expand...

Not really...I have had 3 instances where the water flow alarm went off and not even a degree change in engine temp...I realize that's not exhaust temp but.......

The Aqua alarm goes off at a reduced water flow..not necessarily a complete blockage....a Lehman at reduced power probably doesn't need a huge flow to keep from overheating or setting g off the exhaust alarm...depending what it is set at.

fryedaze said:

Chris, do you have a source for those digital temp indicators.

Click to expand...

They're made by CruzPro (they have a website) and I bought 'em on-line from downwindmarine.com.

My thought was that increasing engine temps can come from several sources (i.e., not just raw water flow).

FWIW, I'm intending to continue swapping out existing analog gauges to their products, as time and budget allows. That way I can set alarms on oil pressure, too. Also, looks like their fuel tank gauges can give me a better idea of fuel consumption -- compared to just guessing, using engine performance curves -- without the expense (and installation) of a real Floscan system.

It turns out that CruzPro's built-in LED backlighting means I can remove a whole bunch of extra circuit wiring -- for dash lights -- under the helm, too.

-Chris

I've got the Cruze Pro tank level gauges.
I installed it 10 years ago. Its singularly one of the best things I added to my boat. Their products are great.

meridian said:

You can purchase a thermal switch disk in any temp range for $10 and hold it on the exhaust elbow with a hose clamp then wire it into your existing alarm system.

Click to expand...

You can tie this into your existing temperature sensor and alarm on the engine.

Fan Limit Switch Therm O Disc 60T12 610064 | eBay