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Post by spiderbill on Jul 5, 2012 15:36:52 GMT
Can anyone tell me where the switch is for my engine compartment exhaust fan? I have a 2011 SO 42DS. I don't see a thermostat or auto control.
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Post by nornaj on Jul 6, 2012 1:27:37 GMT
It is probably the same as our SO39i. i.e. no switch. Fan is on continuously. Couldn't stand the racket. Installed a thermostat and a manual switch at the helm. regards NornaJ
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johnnyboy
Full Member
"Fortune Teller" SO 42 DS 2010
Posts: 41
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Post by johnnyboy on Jul 13, 2012 2:12:48 GMT
i think it comes on when the motor is on.
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Post by sitara on Jul 13, 2012 7:41:52 GMT
The engine compartment exhaust fan is on continuously with the motor in our 2012 SO36i. See Hints and Tips www.jeanneau-owners.com/hintsandtips/variablefan.html for the installation of a variable thermostat switch. This is a mod that I will be doing soon - can't stand the racket either. In the unlikely case of an engine room fire an exhaust fan sucking in fresh air is not a good option so an external cut-off switch for the fan would be a good safety option.
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Post by shiook on Jul 13, 2012 14:07:57 GMT
See also the historical discussions - Many stated Yanmar requires the vent system to ensure fresh air is available for full, clean combustion. I've not modified my 2010 36i until I've heard how well the thermostat alteration works for the motor for a year. I don't like the noise though and do like the solution!
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Post by sitara on Jul 13, 2012 23:14:06 GMT
I would have thought that an exhaust fan fulling air from the engine compartment would have been competing with the engine for air supply.
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Post by Don Reaves on Jul 14, 2012 12:22:32 GMT
That may be true from a technical point of view. But with a large enough intake, the effect would be minimal. But the real issue is to replace the air continuously around the engine with fresh air drawn from outside. The fan will ensure that the air in the engine compartment is replaced much more quickly than would happen if the engine alone had to do it.
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Post by gre2 on Jul 16, 2012 10:58:31 GMT
Our So37 has a thermostat located at the mouth of the hose in the engine compartment that lead to the fan motor. Comes on automatically when the temperature reaches a certain point. Works great but unfortunately I cannot tell you what the switch points of the thermostat are.
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Post by ianqv on Jul 16, 2012 19:07:28 GMT
See also the historical discussions - Many stated Yanmar requires the vent system to ensure fresh air is available for full, clean combustion. I've not modified my 2010 36i until I've heard how well the thermostat alteration works for the motor for a year. I don't like the noise though and do like the solution! Hi All, I#m pleased to say that the mod is still working perfectly!! I have set the fans to come on around 60 degrees. I hope this helps Best Regards Ian
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oasis36i
Full Member
SO 36i Oasis
Posts: 39
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Post by oasis36i on Aug 30, 2012 9:58:58 GMT
I have just purchased an SO36i and noticed that the engine fan is permanently on with the engine. After browsing the interweb, I have concluded this is a good idea.
The fan extracts hot air from the top of the engine compartment via a duct, encouraging cooler air to enter at the bottom via another duct. This cools the engine space generally by circulation (good for all of the electrics), ensures a good supply of cool air for the engine for combustion and reduces hot air entering the rest of the boat.
Resorting to my 20 year old physics, air density is proportional to pressure over temperature. A rise in temperature from room temperature to 100C (roughly from 300K to 400K) reduces air density by 3/4. This reduces the efficiency of combustion; one reason for keeping the engine air cool.
The trick must then be to ensure that the ventilation air intake and ventilation air exhaust are sufficiently balanced so that there is only a slightly negative pressure in the engine bay, thereby minimising the effect on air density, but ensuring that those oily smells get exhausted outside the boat, not into the cabin. I have to assume the boffins at Jeanneau did some tests on this.
So, I have 3 reasons for keeping the fan running: good air circulation to prolong life of all components (n.b. electrics), good cool air for combustion and reducing oily smells in the cabin.
I have one strong reason to stop the fan; I too hate the noise. I will invest in some high quality insulation at some point.
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Post by nornaj on Aug 30, 2012 13:02:11 GMT
Have now had several months operation with the fan on a thermostat plus a manual over-ride at the helm. We usually turn the fan on manually whenever motoring at or near cruising speed (when the fan noise doesn't add much to the engine noise), and off when operating at lower revs. If left off there is a definite build up of engine smell in the back end. So far, the thermostat has never triggered the fan. NornaJ
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