Oil pressure alarm problems (again !)

Claude L.-Auger

Claude L.-Auger

.
Dec 14, 2003
1,450
Hunter 34 Lake of Two Mountains, QC, Can
Some of you might recall a fairly lenghty thread written last year where I described the problems with the Yanmar Panel Buzzer (Panel B-Type) along with the solution found disconnecting the yellow wire coming from the oil pressure switch going into the buzzer and connecting it to the red/white sail drive wire (not used on my boat since it has a shaft) going into the buzzer.
http://forums.hunter.sailboatowners.com/showthread.php?p=1055065&highlight=oil

Same problem has come up again. And the oil pressure switch is good, all connections are good, ground is good. So I figured I'd call my friendly Yanmar dealer and have him quote me a buzzer. Told me Part # 104271-91351. $250 (Canadian) + tax :eek:.

I asked about the part number since last year I had been quoted $102, which I still found high considering a simple radio Shack buzzer sells for less than $10 !

Being frugal I skinned the white and blue wire going into the buzzer (high temp alarm) and connected the yellow wire to it. Sure enough everything works fine. Turn the key, get the alarm and all 3 lamps. Start engine and alarm and lamps shut off. Kill engine and all 3 lamps and alarm come on again until key is turned back off.

I realize that Oil Pressure Switch and High Temp Switch going onto the same diode will make both lamps come on and alarm sound if there is ever a problem, therefore not telling me exactly which is which. Since in both cases one would promptly kill the engine to find out why the alarm is sounding, I am thinking that from that point on I can easily figure out if I have a high temp or low oil pressure problem.

Two questions come to mind: 1) is there any other problems with the solution as stated above and 2) The buzzer is sealed so the diodes cannot be replaced. Can I install external diodes and how would I connect them ?

Thanks for the help. Claude
 
JoeWhite

JoeWhite

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Mar 6, 2008
1,496
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
These buzzers usually have 2 inputs - one that makes intermittent sound ( indicating low oil pressure) and the other is steady ( indicating high water temperature). If your buzzer does not have 2 separate inputs - it is possible that someone has installed the wrong one. You can find the correct one at www.Digikey.com for 24.00.
http://www.puiaudio.com/pdf/AI-4219-P-C48-R.pdf this is an example of the buzzer. This one has only one input. Normally there are 3 screw terminals on the back.
 
Claude L.-Auger

Claude L.-Auger

.
Dec 14, 2003
1,450
Hunter 34 Lake of Two Mountains, QC, Can
JoeWhite said:
These buzzers usually have 2 inputs - one that makes intermittent sound ( indicating low oil pressure) and the other is steady ( indicating high water temperature). If your buzzer does not have 2 separate inputs - it is possible that someone has installed the wrong one. You can find the correct one at www.Digikey.com for 24.00.
http://www.puiaudio.com/pdf/AI-4219-P-C48-R.pdf this is an example of the buzzer. This one has only one input. Normally there are 3 screw terminals on the back.
Click to expand
Thanks Joe, FYI my buzzer is the original Yanmar Type-B panel buzzer. It is sealed, and it has 4 separate entries: red/black wire (12VDC), yellow wire (from Oil Pressure Switch), white/blue wire (from High Temp Switch), red/white wire (from saildrive switch when so equipped). The puiaudio one you show as an example is similar but with only 1 input besides the 12VDC. Have tried to look at Digiket site but lack the knowledge to input the info requested to come up with a part number.
 
Claude L.-Auger

Claude L.-Auger

.
Dec 14, 2003
1,450
Hunter 34 Lake of Two Mountains, QC, Can
Tks Kloudie,
I'm not sure I understand Ken's diagram. I now have only only circuit that still works (white/blue). Since the buzzer is sealed, how can you break the working circuit into 3 different ones ? Other than that and the *&?%$ radar everything is good. I just returned from a 49-day, 1000 miles trip around Lake Ontario and the Thousand Islands. Life is always good on the boat regardless of the various issues.
 
Claude L.-Auger

Claude L.-Auger

.
Dec 14, 2003
1,450
Hunter 34 Lake of Two Mountains, QC, Can
kloudie1 said:
Claude, I think that the diodes go in the wires between the buzzer and its connection with the ground side of the lamp. I think it would be fine to put the diode on the connections at the buzzer. The buzzer and lamp draw less than one ampere, so a small diode will work.
Like this:
http://www.radioshack.com/product/i...ce=CAT&znt_medium=RSCOM&znt_content=CT2032230
Click to expand
Kloudie, I have taken all the tape off from the several pigtails on the panel and did not see any bulge significant enough to indicate the presence of a diode in the lines. Also when I connect the Oil Pressure yellow line to the 1" yellow wire or to the 1" red/white wire I get no sound whatsoever but when I connect it to the blue/white wire (used for High temp sensor), then the buzzer sounds off normally when turning the key and shuts off when engine is started. That I believe indicates that the diodes are inside the buzzer shell and the first 2 are fried and the one connected to the blue/white wire is still good.

Connected this way, all 3 lamps work correctly when supposed to. I will take another look at where the connections with the ground side of the lamps are to check for diodes there but I'd be very surprised if that was the case.

My other solution is to splice a wire to the + side going into the buzzer (red/black wire) and connect it to + side of a small piezo buzzer, then connect the yellow wire from the OP switch to the negative side. Hide the buzzer behind the panel and try it. That buzzer should turn on when turning the key and shut off when engine runs. If it works that's the way it's going to stay. Sure I'll get 2 different sounds one for OP and one for High Temp, but I don't really care. The one we hear all the time when starting and shutting the engine is the one turn on and off by the OP switch.
 
Claude L.-Auger

Claude L.-Auger

.
Dec 14, 2003
1,450
Hunter 34 Lake of Two Mountains, QC, Can
Kloudie, I checked it out and the diodes are indeed inside the Yanmar buzzer and not on the lines to the lamps. I found a real low cost solution: As mentioned in last post I got a 12VDC piezo buzzer ($2.99 CDN) and spliced the Positive wire to the red/black wire going into the buzzer and connected the Negative to the yellow wire going to the Oil Pressure Switch. Works perfectly. Turn the key and the buzzer sounds. Start engine and a second later it stops. Kill engine and it sounds again until you turn key off. The test switch make the Yanmar buzzer sound off as it should and I left the High Temp switch connected to the Yanmar Buzzer. So, besides the lamps, I will now have 2 different sounds alerting me to loss of oil pressure or to high temperature. I tie-wrapped the 2nd buzzer out of sight behind the panel. Rather pleased with the results...and the $3 cost rather than $250. (before taxes !!!). Thanks Joe and thanks Kloudie for the input. Claude
 
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