Engine alarm install

[timjet]

I just installed a Borel raw water alarm in my twin engine ACMY. The instructions say to supply 12v DC power from a source that is switched on when the engine is on. I connected the supply voltage to the unit from the key on hot side of the ignition switch on the bridge of the port engine, ie power to alarm when the key is in the on position. Problem is if the port engine is shutdown for any reason, the starboard engine is unprotected unless I leave the port engine key switch in the on position. I could run an additional wire from the stbd key switch to the alarm the same as the port engine, but I don't think that would be a good idea, having a source of 12v to each engine key switch even with the engine shutdown. I guess installing a diode in the wire from each engine key switch would solve the problem, but wouldn't have a clue on how to do this. Of course I could supply power from anything that is on the bridge that receives power all the time, but I would rather have the alarm powered only when the engine(s) are running, ie engine switch is on. Any ideas??

And along a related matter, I have a fuel transfer pump that will allow transfering of fuel between the saddle tanks. Very convienent until you forget you're transfering fuel, so to preclude this I want to install a small red "reminder" light that illuminates anytime the pump is energized. Since this is a reversable pump controlled by a DPDT switch (I think) I don't think it's a good idea to supply power to the light through the switch. Again, any ideas??

Tim

 

[Capn Chuck]

I guess I am confused. You have twin engines, but installed one alarm?

 

[timjet]

The Borel raw water alarms monitor raw water temperature just downstream where raw water enters the exhaust system. The thinking is that if a problem develops in the raw water system, these alarms will sound long before the coolant alarm thus possibly saving severe damage to the engine. A sensor is installed around the pipe leading to the exhaust. One electrical lead from the sensor goes to ground somewhere on the engine, and the other leads to the alarm unit located at the helm. The alarms can be purchased to either monitor one or two engines. The two engine alarms have two sensor inputs at the alarm unit and 2 LEDs to indicate which engine is tripping the alarm. A 12v power lead goes to the alarm unit to power the system. The instructions say to use a source of power that is switched on and off with the engines and thus the purpose of my question.
http://www.borelmfg.com/products_alarm.htm

 

[FF]

Many folks use a rotary switch that allows the use of the engines , usually second rotary for one for the house .

Hook it to the engine rotary , will function with either engine.

 

[RickB]

timjet wrote:And along a related matter, I have a fuel transfer pump that will allow transfering of fuel between the saddle tanks.

I don't see the point of having a temp switch on one engine exhaust and expecting it to tell you something about the other. If your port engine overheats and you shut it down why do you think that temperature sensor is going to tell you anything about the other engine? If the raw water pump fails on the starboard engine why do you think the sensor on the port engine is going to tell you anything?

And long before this switch thing does you any good at all your fuel transfer pump setup is going to get you fined off the face of the earth when you forget it is running and dump fuel over the side. All the little red lights in the world won't save you from that scenario.


-- Edited by RickB on Wednesday 9th of June 2010 05:54:16 AM

 

[timjet]

Rick,I don't think you understand. Each engine has it's own sensor. One is not dependent on the other. My question concerned the supply voltage for the alarm. By supplying 12v DC power from the engine key start switch, that switch would have to be on in order to power the alarm. If the engine start switch that supplied power to the alarm for whatever reason is off and the other engine is in use, the engine in use would be unmonitored. The simple solution is to install a simple on/off switch from the C/B panel on the bridge to the alarm. I would have to get in the habit of turning this switch on when using the engines.

RickB wrote:
And long before this switch thing does you any good at all your fuel transfer pump setup is going to get you fined off the face of the earth when you forget it is running and dump fuel over the side. All the little red lights in the world won't save you from that scenario.

-- Edited by RickB on Wednesday 9th of June 2010 05:54:16 AM

The exact purpose of the red light.
The boat came from the factory with a fuel transfer pump because the genset feeds from the port tank only. The genset burning half a gallon an hour, and running the air conditioner for 8 hrs at night during the summer and it wouldn't take too many nights out before you would have a huge fuel imbalance, hence the purpose of the transfer pump.


I just bought this boat and the current setup has the transfer pump switch located underneath the instrument panel in an area that is not easy to see. It would be very easy to forget you are*transferring*fuel and installing a light on the instrument panel would be a reminder that the pump is on.
Now, how do I install this light??


Tim

*




-- Edited by timjet on Wednesday 9th of June 2010 07:46:11 AM

 

[koliver]

You will also have a crossover line so that the more full tank will flow over to the less full side, until equilibrium is reached. This will not work if your boat is unevenly loaded, but most of us don't load with a deliberate list, so in most cases, that is all you need. It will have a valve on it, so you can isolte each tank. In my boat, the Espar and the diesel stove pull from the port tank and the genset from the Sb side. In the cooler months, we tend to tie to docks and use the heat stuff, and in the summer, anchor out and use only the genset, so I have opened that valve to correct the development of a fuel load list. It takes only 1/2 hour to correct, then close the valve.

 

[timjet]

Interesting. I'll have to get my manual out to see if I have that gravity fed transfer line. Since a transfer pump is factory installed, my guess is no.

 

[RickB]

timjet wrote:Rick,I don't think you understand.

You are right.

*

Take 12V power through an appropriate fuse from wherever you can easily obtain it and power one side of each switch. The wire from the other side of each (normally open) switch would lead to one side of a "little red light" and through a diode to one side of the warning buzzer. If either switch closed due to overtemp it would direct power to the appropriate light and through the diode to the master warning buzzer. The diode is there to prevent the other light from illuminating when one switch closes.

Dead simple.

And again, no matter how many little red lights you use to remind you that the fuel transfer pump is on, you will forget it. If you have a pump installed like you describe, just remove it and install a piece of tubing and a valve in its place. You would then have an equalizing line that you can use when and as you desire.


-- Edited by RickB on Thursday 10th of June 2010 08:41:59 PM

 

[Arctic Traveller]

I just purchaced the exact same alarm system for our twin engine Defever.* As delivered from the factory, there is only ONE power wire for both alarm sensors.* My plan is to simply power it off one engine switch, and if a problem develops requiring me to shut down one engine, I'll simply solve the problem right away and restart the engine once the impeller is replaced or the strainer is cleaned. Another option would be to use a relay wired to allow only one engine at a time to energize the coil. As for the fuel transfer pump, I added a wind up timer switch in the supply circuit, the same as used for shower fans or public restroom lights.* I also have one on the macerator pump.* They come in a varity of time intervals, and are dead simple to install, as there are only two wires.* Works for us. If you really wanted an indicator light, simply wire one side of the light to the power wire to the pump, the other to a convenient ground. If you use a ground in the pilot house, you only have to run one wire from the engine room...........Arctic Traveller

 

[RickB]

timjet wrote:

Problem is if the port engine is shutdown for any reason, the starboard engine is unprotected unless I leave the port engine key switch in the on position.

That is why you shouldn't power off the switch. Why complicate things and disable the other sensor at the same time? Just fuse the 12V supply and be done with it.

 

[timjet]

Arctic Traveller wrote:

My plan is to simply power it off one engine switch, and if a problem develops requiring me to shut down one engine, I'll simply solve the problem right away and restart the engine once the impeller is replaced or the strainer is cleaned.

I'm not sure that is a good idea for me. I would want to have the ability to continue on with one engine knowing that it is properly monitored. Additionally, the impeller on the port engine is impossible for me to get to. At 6'3" I can't store my legs anywhere to get to it!

Since you have installed the system I will comment. In talking with another boater who installed one expressing my concern about the clamp that is included with the alarm, he mentioned that he installed an additional SS hose clamp to more securely attach the sensor to the exhaust hose. I will do that and fashion a small rubber protector on top of the sensor and underneath the new SS hose clamp. He also suggested testing the sensor with a heat gun periodically, which I think is an excellent idea. Such a cheap and simple system for added peace of mind.

Where did you find a DC wind up timer?

*


-- Edited by timjet on Friday 11th of June 2010 06:07:01 AM

 

[timjet]

RickB wrote:

*
Rick Wrote:

That is why you shouldn't power off the switch. Why complicate things and disable the other sensor at the same time? Just fuse the 12V supply and be done with it.


Rick,
Your're right. I've gotten it to complicated. I will use power from elsewhere on the bridge and provide a fuse. I do like your diode idea and if I were more knowledgeabe would probably do it.


*

 

[Arctic Traveller]

timjet wrote:


Where did you find a DC wind up timer?

*

They are available in about any electrical supply store, and places like Home Depo, Lowes etc. I was in Home Depo today and saw them while getting a timer for our water heater (no reason to let it run 24 / 7)* They are not specifically rated for DC only, but can more than handle the limited amount of current from a small pump.* Just to be sure, check the name plate data on the pump, then check the switch rating prior to buying.* The DC rating will be less than the AC rating, but it should still be well within the capacity of the switch to handle. ...................Arctic Traveller

*

 

[FF]

Backwoods Solar has them in their catalog.

Most will need to use a relay if over 4-5A is controlled by the timer.

WE use them to time 2 hours of engine driven refrigeration , easier than a log entry.

AND you never "forget" to secure the unit.

 

[timjet]

koliver wrote:

You will also have a crossover line so that the more full tank will flow over to the less full side, until equilibrium is reached.

A simple soultion to a problem, however a hole in the bottom of a fuel tank will eventually leak. The transfer pump does require one to pay attention, but you will never have a fuel leak due to a hole in the bottom of the tank.

 

[timjet]

OK, I got this figured out. First I supplied power for the alarms from the engine blower switch. The blowers are supposed to be on anytime the engines are running so they became a logical choice.

Second concerning the fuel transfer pump; my opinion the pump is a better option than having a gravity fed fuel transfer line between tanks for the simple reason the pump does not require the transfer lines be plumbed into the tank from the bottom. A hole in the bottom of a fuel tank will eventually leak allowing fuel into the bilge which will eventually be pumped overboard by the auto bilge pump. If you are lucky enough to just happen to be aboard when the leak develops you will limit the spill. If not .....

The transfer pump is a better option in my opinion and with a LED that illuminates when the pump is energized, a good reminder that the pump is operating. Yes if you forget the pump is on you will indeed eventually pump fuel overboard through the fuel vent, but the LED should remind you that it is on. I successfully wired the pump and switch with two LED's in such a way that when the transfer pump switch is moved toward the port tank the LED on the left side of the switch illuminates and vis a versa. The mechanics of how this is wired is to understand how a DPDT switch works (this switch allows reversing the polarity of the pump), and with the knowledge that an LED will only illuminate with the proper polarity. A blinking LED can be used to further grab your attention.

 

[FF]

A somewhat simpler and perhaps easier to operate "Cure" might be a Cole Hersee key switch as used with auto stule terminals.

Most diesel start switches lack an ACC output.

AS in your car this powers items that should be OFF during the start, like the radio, heater fans etc.

Simply power what you need from the acc position.