Alarm sounds even before glow plugs warmed

[OS2Dude]

I recently installed a newer engine panel in the cockpit of our 1985 Catalina 30 similar to this one by CatalinaDirect. I found just the plate in a swap shop while visiting FL. I wired my existing meters along with a new alarm and lights I got from CD as in the panel above and now there is an ear splitting sound as soon as I turn on the ignition. It sounds the entire time I'm warming the glow plugs, until I crank the engine. The engine starts fine, no issue there, but I like to go out at night once in a while and I would rather not wake the folks who live aboard around me.

Is there a circuit I can add to the alarm (Low Oil Pressure) so it won't sound for 30 - 45 seconds? Perhaps a capacitor or something to delay it? I don't mind the light coming on immediately.

The original alarm was a little pizzo buzzer thing that made no sound at all, and the original lights were broken. Original panel was a gold decal on black plastic and was scraped so bad it could not be read...

Engine is an M-25

 

[bawlmer]

That is the same panel I have on my 270. A low oil pressure alarm usually precedes a catastrophic failure if the engine is not immediately turned off. I don't know if a delay is a good idea. You can order a replacement buzzer from Catalina Direct. I did. It is not that loud. If you insist on going the delay route you can buy a time delay module from an electronic supply house. 15 years ago I could give you a bunch of them off the top of my head. Today not so much. Maybe the audio level of the buzzer is just relatively higher than the old defective one it replaced. You can also put tape over the transducer to lower the sound level. Also there is a glitch on that panel that concerns the low oil alarm. Catalina may have fixed it by now. Check and see if the low oil light lights up when the alarm sounds. If it doesn't you can hook the OP light up in series with the buzzer. The buzzer will then sound very sickly and low. I discovered this the hard way. Probably not the factory fix though.

 

[bawlmer]

Chris. Please disregard the part about the OP light. I just read that yours lights up. Catalina must have solved the problem. My apologies.

 

[OS2Dude]

That is the same panel I have on my 270. A low oil pressure alarm usually precedes a catastrophic failure if the engine is not immediately turned off. I don't know if a delay is a good idea. You can order a replacement buzzer from Catalina Direct. I did.

The buzzer is new from CD. The old original buzzer was very quite, almost non-existent. In a perfect world I'd like it so the alarm would not sound until the engine was running. That would take care of the concern about a valid Low Oil Pressure alarm not being delayed. Maybe some kind of relay with the volt meter input? (That is only active with the alternator running, correct?)

 

[Laszlo]

Mine is so quiet I can hardly hear it. The light works but faint. Replaced buzzer no luck. If I switch wire to high temp warning I get loud alarm.

Laszlo

 

[bawlmer]

OP alarm is from a on/off sensor on the engine. It is a normally open switch that is lightly grounded through a pull down resistor on the engine. This causes the alarm to sound. It's the default state of the circuit so I don't know if a delay will be effective. Also your buzzer is dual purpose as the other terminal is the high temp alarm. It makes a beeping instead of steady tone. I think the answer is to mechanically dampen the sound of the buzzer with tape or cloth or both. I wound up with a spare buzzer due to an issue on my panel which I incorrectly diagnosed. Turns the PO had all the warning lights and buzzers disconnected. I hooked everything back up and found a factory service bulletin that solved the problem. It sounds like you have an updated version of my Seaward High Efficiency Panel. Everything as you described seems to be working to factory spec and I would advise against adding additional complexity. From my previous adventures I know way too much about these circuits. I will be happy to send you my old functional buzzer if you PM me with your address but I think it will be as loud as the one you have now.

 

[bawlmer]

Lazslo. Disconnect the Low OP light and the buzzer will work fine. That is what got me spun around. I have attached the service bulletin from Catalina that addresses this and other issues. Look on page 2 in the LOW OIL PRESSURE LIGHT section in the middle of the page. Hope that helps.