12 volt solenoid controlled engine water thru hull

[67c&ccorv]

Can't find the original thread where I posted on this subject but here is the engine inlet water supply electric solenoiod thru hull ready for installation in my vessel;

It is a 12volt DC powered valve that is normally closed and operates when the ignition switch is turned "on".

Draws 20 watts when operating...LED indicates it is powered up.

If the valve fails I can remove it - insert a hose barb - and reconnect the inlet water line to the engine.

[ndutton]

20 AMPS?? Mama Mia, that's a spicy meatball! And that's long continuous load. You're asking an awful lot of your ignition switch and wiring. Please keep a wary eye on the recommended amperage of each.

edit:
I just did a quick voltage drop calculation and assuming 15 feet wire length (to the panel and back) 4 amps ignition load, 20 amps valve load and maximum 3% allowable voltage drop for the system, you need #6 wire for the ignition circuit. To double check I ran the same calculation excluding the 20 amp valve and the wire size came up to 14 gauge (nominal, within 2% of the table figure). Brutha, this is a red flag for me.

You might consider a relay for the valve load.

[hanleyclifford]

Sure won't have to worry about excessive voltage at coil+.

[smosher]

Originally Posted by hanleyclifford

Sure won't have to worry about excessive voltage at coil+.

HAHA There's another fix to excessive volts at the coil

[67c&ccorv]

Originally Posted by ndutton

20 AMPS?? Mama Mia, that's a spicy meatball! And that's long continuous load. You're asking an awful lot of your ignition switch and wiring. Please keep a wary eye on the recommended amperage of each.

edit:
I just did a quick voltage drop calculation and assuming 15 feet wire length (to the panel and back) 4 amps ignition load, 20 amps valve load and maximum 3% allowable voltage drop for the system, you need #6 wire for the ignition circuit. To double check I ran the same calculation excluding the 20 amp valve and the wire size came up to 14 gauge (nominal, within 2% of the table figure). Brutha, this is a red flag for me.

You might consider a relay for the valve load.

How about wired to my house battery bus bar and activated by separate switch?

These are the tech specs for the valve;

http://www.stcvalve.com/STC-DOWNLOAD/2S160-500.pdf

[joe_db]

Where did you get 20 amps?
I see 14 to 20 *WATTS*. At 12 volts make that 1 to 2 amps.

[hanleyclifford]

I really like this idea but have a couple of reservations. The circuit should be isolated from the ignition by means of a separate oil pressure switch unless this is intended to be part of the coil resistor plan. Secondly, this valve is stainless and should be isolated from the (less noble) bronze thru hull with a non conductive close nipple or fitted with a zinc which would make a mess in the bilge.

[67c&ccorv]

Originally Posted by joe_db

Where did you get 20 amps?
I see 14 to 20 *WATTS*. At 12 volts make that 1 to 2 amps.

Geez...you are right Joe!

I just spent the last hour on the STC website looking at all the electrical info they had;

...in the wiring diagrams for the coils they suggest using 18awg size wire - which is what comes with the pre-wired units.

And I hooked up the unit to one of my low powered transmormers and it worked fine - whacking myself on the head because when I initially investigated the units I specified that I wanted one that had a low power draw!

Sorry guys!

[ndutton]

Whew, I can breathe again. Ignore everything I said.

[Sailwood]

I don't know if anyone else has commented or if my immediate concern has been expressed by others, but something bad bugs me about leaving the engine cooling up to an electronic gizmo. Did I miss something in the thread?

Doug Soden

[67c&ccorv]

Originally Posted by Sailwood

I don't know if anyone else has commented or if my immediate concern has been expressed by others, but something bad bugs me about leaving the engine cooling up to an electronic gizmo. Did I miss something in the thread?

Doug Soden

This idea is in response to the problem of constantly having to open and close the engine intake water thru hull fitting which is located in a difficult to reach location under my port cockpit locker on my C&C Corvette.

You literally have to hang upside down to open/close the thruhull - makes for Chinese fire drill if anyone is sitting on the port cockpit locker as I shut off my water intake every time I turn the motor off and begin sailing.

The idea is that one opens the manual thruhull fitting at the start of the day and then it is left alone for the duration of the trip-day-sail whatever?

Water will only be admitted to the engine when the key is turned on and the engine is running.

The valve is a normally closed valve which has an LED indicator to indicate it is working - if it fails I have an engine water flow alarm and hot engine alarm detector.

I should point out the these valves are extremely well made (all 304 S/S) and are routinely used in industrial processes/manufacturing systems where failure is not an option.

Should be enough to alert me to shut the engine down in the event of valve fail.

Will be mounting the system this coming week or two with launch on July 16.

Cheers!

[toddster]

Nice idea. Is the LED on the dash panel or down in the bilge? Theoretically, one could do the same for the exhaust. Even the fuel, I suppose, but I don't think I'd want to do away with manual engine checks at start up.

I have similar solenoid valves on lab equipment that operates every day - they open when the equipment is powered up and stay that way all day. They last about 5 to 8 years. Sometimes the AC-operated ones start "buzzing" which is a little annoying and makes me a little nervous about their longevity.

[67c&ccorv]

Originally Posted by hanleyclifford

I really like this idea but have a couple of reservations. The circuit should be isolated from the ignition by means of a separate oil pressure switch unless this is intended to be part of the coil resistor plan. Secondly, this valve is stainless and should be isolated from the (less noble) bronze thru hull with a non conductive close nipple or fitted with a zinc which would make a mess in the bilge.

Hanley - I am not too worried about the corrosion issue as I am in fresh water and I use a sealant on the threads which insulates the parts from one another.

If I was in salt water I would taking an "all the same metals" approach.

Don't know if you can see it but the s/s bolts are insulated from the bronze thruhull base by nylon washers and insulator on the threaded portion that contacts the base.

Cheers!