Engine Panel Alarms

mregan · April 30, 2017, 03:41:55 AM

Did the '86 have a low oil pressure alarm and a high engine temp alarm. I replaced the panel this winter (kept all the gauges) Marked everything on the back of the panel and what I disconnected on the boat. Was there today. Got everything wired up but the alarm. I realized I only had one alarm and some small circuit board that was wired into the alarm. Was getting confused how to wire the alarm and the low oil pressure light and engine alarm light (lights never worked on the old panel) Looked at the wiring diagram I had from the alternator to volt meter change. Showed 2 alarms buzzers. Was looking on Catalina direct and they made mention that boats before 1990 didn't have a high temp alarm, only low oil but there is a part you can buy for the engine to add a high temp alarm. Will check tomorrow to see if PO had installed that part. If not, I'm assuming I wire the alarm to the low oil pressure. If that's the case, what would turn on the high engine temp light on the panel?

Ron Hill · April 30, 2017, 02:39:30 PM

mre : Look at your old panel and see if there is a "dog house" shaped PC board on the back of the temp gage. if there is, that PC board needs to be taken off and mounted on the back of the new temp gage.

That is only one of the two types of Hi temp alarms. It changed analog movement of the needle to digital and set off it own hi temp buzzer.
The other involves a second lead off the engine thermostat housing.

A thought

mregan · May 01, 2017, 06:21:52 AM

Ron
I do have the dog house panel. That explains part of the wiring confusion. My other problem is some of the labels I attached to the wiring fell off so I can't figure out how to wire the buzzer to both alarms. When the new panel came in, I pulled all the gauges off the old panel and installed them on the new. All the diagrams I can find show the 2 separate buzzers.

Ben H. · May 02, 2017, 06:52:37 PM

Quote from: Ron Hill on April 30, 2017, 02:39:30 PM
The other involves a second lead off the engine thermostat housing.

Ron,

Could you explain this other method? I don't have said dog house and am looking to wire up a new dual buzzer I have for the control panel.

Dave Spencer · May 02, 2017, 07:23:42 PM

Ben,
I have an M35A engine but I suspect the answer is similar for the M25. I've attached a picture of my thermostat housing. The temperature gauge sender is at the 6 o'clock position and the temperature alarm switch is shown at the 9 o'clock position. The switch has a single wire that goes to the High Temp alarm at the engine panel. There are some schematics in the Tech Wiki that show this. While they aren't exact to the Catalina configuration, the schematics show what I think you need fairly clearly. The question is whether or not you have a blank port that can accommodate a switch. If not, it would be a relatively simple matter to tap a new hole (although this would certainly require some bravery!)

http://c34.org/wiki/images/9/9c/A_and_B_series_engine_schematic_12b-82b_108c_%2839144_rev_m%29.pdf

Stu Jackson · May 02, 2017, 08:10:11 PM

Quote from: Dave Spencer on May 02, 2017, 07:23:42 PM
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If not, it would be a relatively simple matter to tap a new hole (although this would certainly require some bravery!) .........................
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Many skippers have reported doing this tap for many, many years. If I find a link, I'll post one, but I wouldn't be surprised if it's in the TECH NOTES and/or on this forum.

mregan · May 03, 2017, 07:50:13 AM

Ben
If you don't have the temp alarm switch in the thermostat housing (my M-25 (1986) doesn't) I think you need the dog house control board. From what Ron mentioned and what I could find online, the control board converted the temp signal somehow and it would act like a high temp alarm switch and it allowed the one buzzer to act as a high temp alarm buzzer and low oil pressure buzzer. If you had to go with 2 buzzers, you need the additional temp alarm switch in the t-stat housing.

mregan · May 03, 2017, 08:04:24 AM

Just did a search of tapping a new hole in the temp housing. Someone had previously mentioned removing the pet cock and installed the temp alarm in the pet cock hole. I'm going to take a look at mine. Wondering if you could pull the petcock, install a T fitting and re-install the pet cock and put the temp alarm on the other side of the T.

Stu Jackson · May 03, 2017, 08:22:21 AM

The only reason for the petcock on the top of the housing is to remove air from the loop to the water heater. My guess is you could remove the petcock completely. I haven't used mine in 17 years.

Engine Overheating 101 - How to Burp Your Engine (Reply #6) http://c34.org/bbs/index.php/topic,4518.msg26462.html#msg26462

Maine Sail put an automatic air vent on his engine. I don't think we have room above ours to do that.

KWKloeber · May 03, 2017, 04:04:14 PM

I wouldn't tee the hi temp switch unless I did a laser thermometer check to see if the switch was "seeing" the same temp as it would inside the housing. Maybe that's overkill. It's easy to drill and tap for the 1/8" temp switch (if you can get the cap bolts off,) and it's not a bad idea anyway to change the thermostat anyway while you're in there.

One of the downsides of the location of the sender and switch we have on the T caps, is maintaining a good engine ground with the rust, bolt corrosion, thermostat gasket, etc. I've been putting a bonding jumper into my harnesses lately -- that clamps onto the temp gauge sender and jumpers to the nearby alternator ground post. I have also just added oil pressure senders to an M-25 and an M-25XP, and also jumper a ground bond wire to the oil switch/oil-pressure sender bracket (like are used on the A-series and B-series engines.)

Quote from: mregan on May 03, 2017, 08:04:24 AM
Just did a search of tapping a new hole in the temp housing. Someone had previously mentioned removing the pet cock and installed the temp alarm in the pet cock hole. I'm going to take a look at mine. Wondering if you could pull the petcock, install a T fitting and re-install the pet cock and put the temp alarm on the other side of the T.

Ron Hill · May 04, 2017, 02:53:46 PM

mre : You already have the "dog house " hi temp PC board alarm. Remount it on the back of the temp gage!!
As the analog temp needle goes thru 190F degrees the digital signal sounds the alarm. The PC board has it's own built in buzzer alarm!!

I even wired in a "press to test" spring loaded toggle switch which is wired from Sender to Gnd.
I periodically "test" the alarm to make sure it is operational.

A few thoughts

KWKloeber · May 04, 2017, 04:41:26 PM

Just remember that those Seaward inventions do fail, not if but when. And you'll be adding a hi temp switch then anyway. There's no replacements available.

kk

Quote from: Ron Hill on May 04, 2017, 02:53:46 PM
mre : You already have the "dog house " hi temp PC board alarm. Remount it on the back of the temp gage!!
As the analog temp needle goes thru 190F degrees the digital signal sounds the alarm. The PC board has it's own built in buzzer alarm!!

I even wired in a "press to test" spring loaded toggle switch which is wired from Sender to Gnd.
I periodically "test" the alarm to make sure it is operational.

A few thoughts