Engine alarms: If you have one, how is it wired?

[TomY]

I have an ancient WIC Marine alarm. Old but it works. It has an On - OFF switch with a third position, TEST. I like having the lights in the cabin with a horn loud enough to hear in the cockpit.

ON, has a small green indicator light to tell you it's energized.

TEST, lights 3 bright red lights, Oil, Temp., Gear.

As well as a - + leads, there are 3 to senders. They all use the - side to close the switch. That's standard (I think) as senders only have one wire, that closes or opens the circuit on the - side.

My question is on hooking the (+) up to the engine panel. Connected to the keys ON post, the alarm goes off when you turn the key (because the Oil pressure sender is closed - no oil pressure when engine isn't running). It's loud and annoying while you heat the glow plugs.

I'm thinking, #1 - move the glow plug (+) to OFF post on the ignition switch(which has power if the engine battery is ON).

Or #2 - add a switch at the panel to turn the alarm off an on (and leave the alarm ON all the time).

Any ideas what works best?

 

[uncledom]

Generally the positive lead is connected to the horn and or lights and ground fron any sensor completes the circuit and fires it off.

 

[TomY]

Generally the positive lead is connected to the horn and or lights and ground fron any sensor completes the circuit and fires it off.

Yes, I know how it works, not changing any wiring to the senders on the (-) side.

I'm asking how people connect (+) to their ignition. As it is now, mine is usually OFF so as not to listen to the alarm while I energize the glow plugs. Engine running, Oil sender switch opens and turns horn off.

Then I have to remember to turn the alarm ON, for it to work.

 

[uncledom]

It goes to the “on” position of the ignition switch instead of the toggle switch. This way every time the key is in the on or run position the circuit has positive power.

 

[TomY]

It goes to the “on” position of the ignition switch instead of the toggle switch. This way every time the key is in the on or run position the circuit has positive power.

Then the alarm sounds, as you heat the glow plugs, for about 10 seconds. That doesn't work for me(hence, I turn it off at the device-first post). And the reasoning behind #2; second ON-OFF switch for alarm, at ignition panel.

Do others just tolerate the horn? Perhaps my horn is louder than most. I notice more recent alarm systems have no central device with lights and an On-Off switch.

 

[TomY]

Maybe I have answered this myself. I could simply move the glow plug solenoid (+) from the ON to the Batt. post on the switch. Then on starting: Energize the glow plugs, then turn ignition to ON and start. My engines glow plugs are manually activated.

Just a short dying horn sound, as the Oil sender switch opens and turns horn off.

That way I don't have to remember a second switch (and don't have to install one). At shut down, once key is turned OFF the horn won't sound.

I can't see a problem the glow plug circuit is separately fused.

Last fall, after changing the oil, I started the engine. I noticed the oil gauge (which has a separate sender), was only up to half it's usual reading. By the time I realized something was wrong and shut the engine down,...I had nearly 5 quarts of fresh oil,...in the bilge. As you probably guessed, the filter wasn't tight.

 

[uncledom]

My glow plug “on” is turn the key to the left, my “run/start” is turn the key right.

 

[uncledom]

From what you describe, your glow plugs are on when ever the engine is running. Maybe you need to start with a new ignition switch.

 

[TomY]

From what you describe, your glow plugs are on when ever the engine is running. Maybe you need to start with a new ignition switch.

Then I'm obviously making a mess of my written description.

My ignition switch only energizes a push-switch, that closes a soleniod (on it's own fused circuit), that energizes the glow plugs(which are old style and draw higher amperage).

Thanks!

 

[DArcy]

Another option would be to install a normally closed momentary push button switch in line with your horn. This would silence the horn as long as you hold it but activate it when not pushed. That way you could avoid any horn noise at all when starting, or allow it to test when you want.

 

[TomY]

Another option would be to install a normally closed momentary push button switch in line with your horn. This would silence the horn as long as you hold it but activate it when not pushed. That way you could avoid any horn noise at all when starting, or allow it to test when you want.

That's an idea. The best part being; with a momentary switch, you couldn't forget to turn the alarm back ON.
Brilliant, DArcy! For now, I think I'll just connect the switch to the glow plug solenoid, to BATT, and see how that goes. I'll keep your idea in mind.

The best alarm would not require any turning on (like the typical units sold that use a horn, only). And have an ON indicator light, so you can see it's powered. Plus a test switch to assure the alarm side, is working.

I love the exhaust alarm I mounted just above my water lift muffler. It has a simple band that holds the sensor against the exhaust hose. The sensor closes at 200F and sounds an horn and a red light. Best of all, it can be wired into the ignition circuit so it's always on when the engine is running. Fool proof.

 

[Juanona]

I love the exhaust alarm I mounted just above my water lift muffler. It has a simple band that holds the sensor against the exhaust hose. The sensor closes at 200F and sounds an horn and a red light. Best of all, it can be wired into the ignition circuit so it's always on when the engine is running. Fool proof.

Hi Tom, what exhaust alarm did you install? The one I found online seems to require tapping into the exhaust hose (and is a bit pricy, not that it isn’t worth it). My original temp alarm still functions but it’s one of those things that a simple backup would be a good idea.

Edit: in 2015 while making landfall in Norway the alarm went off, the engine was overheating. But the impeller looked like new. I went through the SW cooling A to Z and couldn’t for the life of me find what the issue was. I decided to replace the impeller while it was out and discovered that it was spinning on its hub. Something to suspect in an otherwise perfectly good looking impeller.

The weather has been beautiful here in Europe and we are through the Kiel Canal heading east. Happy sailing to all.

Max

 

[TomY]

I love the exhaust alarm I mounted just above my water lift muffler. It has a simple band that holds the sensor against the exhaust hose. The sensor closes at 200F and sounds an horn and a red light. Best of all, it can be wired into the ignition circuit so it's always on when the engine is running. Fool proof.

Hi Tom, what exhaust alarm did you install? The one I found online seems to require tapping into the exhaust hose (and is a bit pricy, not that it isn’t worth it). My original temp alarm still functions but it’s one of those things that a simple backup would be a good idea.

The weather has been beautiful here in Europe and we are through the Kiel Canal heading east. Happy sailing to all.

Max

Hi Max, we envy your weather!

This is the alarm I installed:

Easy install, no cutting into anything, just pull the metal strap tight and that's it. Stays put. Wiring is simple too.

On my OP, I ended up simply moving my alarm power lead (for both high coolant temp, low oil pressure alarm senders) to the BATT-ery post terminal on my ignition switch. Now I can push the switch to the solenoid that operates the glow plugs, before turning the ignition key to ON.

The alarm sounds briefly as I twist the key to ON - START, then goes off as the engine fires.

I always enjoy the posts and pics from your cruise.

 

[Juanona]

Thanks Tom, we will be home for a wedding in June (my son’s) so I will likely order one of those units. I just wrote the manufacturer to make sure it can sense through a heavy walled, ribbed exhaust hose which I installed this past winter.

Thank you for your comments; Lynnie is just finishing up her first blog of the season. We love being out on the water again.

Max

 

[dziedzicmj]

we are through the Kiel Canal heading east

that Baltic Sea can be quite cold in April. Stay warm.

 

[Juanona]

I already got a reply from Aqualarm: “(The sensor) is designed to go on the rubber hose part of the exhaust. If you think you have an abnormally thick hose, you may attach it to the metal part of the exhaust. The detector is set at 200 deg F, so you should not get any false alarms. I think most normal operating temps are around 180 or 190.” I will get one when I’m home in June; thanks Tom.

Dziedzicmj: we have a nice Reflex heater and manage fine when it’s cold. That said it has been short sleeve and suntan lotion weather here in Germany so far. Suspect we will get some cold blasts and the water is still quite cold. Happy sailing to you. My mom was from Ottawa and I am proud of my Canadian roots!

 

[DArcy]

Max, you are much better off in Kiel right now than Ottawa. We still have ice in the harbour. I was in meetings the last few days with people from Hamburg and they were saying how nice it is there this spring.

 

[Hagar]

I already got a reply from Aqualarm: “(The sensor) is designed to go on the rubber hose part of the exhaust. If you think you have an abnormally thick hose, you may attach it to the metal part of the exhaust. The detector is set at 200 deg F, so you should not get any false alarms. I think most normal operating temps are around 180 or 190.” I will get one when I’m home in June; thanks Tom.

The engine coolant will run 180 to 190°F but the exhaust temperature will be much lower since it comes into direct contact with the raw water. When I check ours with my hand it is only "pleasantly warm" I would think not more than 100-110°F.

 

[TomY]

The engine coolant will run 180 to 190°F but the exhaust temperature will be much lower since it comes into direct contact with the raw water. When I check ours with my hand it is only "pleasantly warm" I would think not more than 100-110°F.

I think you're right. I was concerned as I couldn't get quite the distance between the cooling elbow and muffler recommended by the water lift manufacturer. To be sure, I mounted the temperature sensor band just below the elbow. The hose is only warm and sensor never closes. I'm sure it would close very quickly the raw water strainer is clogged, even faster if you forgot to open the raw water intake.

 

[centerline]

Maybe I have answered this myself.

I could simply move the glow plug solenoid (+) from the ON to the Batt. post on the switch. Then on starting: Energize the glow plugs, then turn ignition to ON and start. My engines glow plugs are manually activated.

there you go! depending on how the glow plug system is wired, its not good to push that many amps thru the keyswitch anyway. (some systems dont have a GP relay, but are wired direct thru the button/switch)..

I like the buzzer to sound when the key is in the ON position with the engine NOT running, as this reminds anyone who pulls the engine kill cable to shut the switch off too.... most of the newer diesels and gassers dont have the issue like some of the older diesels did with the glow plug button and kill cable.

a toggle switch in the warning sensor line could be forgotton and leave the sensor circuit off all the time, and if one has a catastrophic engine failure when the engine is fully equipped with warning devices, but the operator FORGOT to turn the switch on that he installed, is a top nominee for a Darwin Award...