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What temp for thermal switches for e-fan?

mini_mull

mini_mull

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I was wondering what the ideal temp for thermal switches would be if I were to run dual electric fans (ie windstar). I run a stock 195* thermostat that keeps my TBI happy. I was guessing 200* for the first and 205* for the second would be ideal. Are these the kind I would need? Some are listed normally open and some normally closed, would one make wiring simpler (like I wouldn't have to wire my relays backwards)? Which one?

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=MBI&PartNumber=RF993655&Description=Thermal+Switch

Please weigh in on whether that would be the optimum temps.
 
good ??? I just picked one up at the scrap yard today for $50 and I dunno how to hook it up. I need to review the tech writeup. Do you run seperate switches or run both off the same one? that makes alot of sense to have them seperate though!
 
200* may even be a bit low. I'd say somewhere around 210* if you can do it, that's still only 15* over a normal thermostat temp, yet enough that coming to a stop at a light, the fan may stay off.
 
Actually being in AZ, I NEED the A/C to come on at every stop light, esp in the summer time (April-October). Might wear out the motor faster, but if I wire them separate and pick up an extra motor when I can, it should work good, and be dependable. I'll probably wire them each to have a separate manual on too, for the really hot days when I want to switch on both at the light to bring that condensor's temp down even faster.
 
CutlassKid85 said:
thats the same one I'm using. Only issue I'm having with it is sometimes it won't come on until the motor is sitting around 225-235, but after it finally kicks on that first time it turns on at the right temp for the rest of the trip. :doah:
Click to expand...

Yea I had to have the thermo switch replaced because the first one was faulty
 
I picked up a temp switch that kicks my fans on at 200 that screws into the top of my water pump. Works great.
 
mini_mull said:
Actually being in AZ, I NEED the A/C to come on at every stop light, esp in the summer time (April-October).
Click to expand...

Yes, with A/C on, the fans MUST be running unless the vehicle is at high speed. I have mine wired so that the fans turn on whenever the compressor is running. I have two fans, each with it's own relay. All you need to do this is a diode from the clutch to both relay coils. This makes an OR function so that the fans turn on whenever the temp is high enough OR the compressor is running.

You could also make a way to turn the fans off above a certain speed, but I'm thinking the ultimate way might be a temp sensor on the condensor coil + a temp sensor on the radiator. Then both would connect to the relay coil through a diode.

I don't think a manual switch is a good idea. If you run the A/C without the fans on, the high-side pressure skyrockets until your high-side safety switch trips (if you have one) or you vent refrigerant through the safety valve on the back of the compressor.
 
Mine both turn on at the same time, through the temp switch or if I cut the A/C on, they shut off at 175, I have yet to see them shutoff once they've turned on... except when I turn the key off... damn the heat.:crazy:
 
dyeager535 said:
200* may even be a bit low. I'd say somewhere around 210* if you can do it, that's still only 15* over a normal thermostat temp, yet enough that coming to a stop at a light, the fan may stay off.
Click to expand...

With the WInstar fans on my ElCamino, using a 185* stat, I just wired both fans together and used a switch that turned on at 210 and off at 190. Most of the time, it wouldnt come on unless I was sitting at a long light on a hot day and when they did, they brought the temp down pretty fast. Couldnt see any reason to run the two fans separate. Also had a wire from the A/C compressor to the relays so when the air was on, the fans were on basically over riding the switch.
 
are you guys running these fans by themselves or in conjunction with the manual fan? and do you have them mounted as pushers or pullers? ive been thinking bout add electric fans but havent got around to it yet.
 
mr.smartass said:
I picked up a temp switch that kicks my fans on at 200 that screws into the top of my water pump. Works great.
Click to expand...

part number?

The reasons for running separate switches would be so that if anything went wrong with one circuit, I could keep right on going with the other, no worries. It'd also keep there from being such a load on the electrical system when both switched on at the exact same moment. It would also keep less wear and tear on the motors since I'm guessing that sometimes just one coming on would kick the temp down fast enough that the other one never kicks in. It's not necessary, but I can't think of any reason not to do it, unless I can't find enough places for switches. I think having a temp sensor in the condensor would be great because I'm not sure my compressor ever switches off in the summer, even at speed. But I'm not sure how that could be installed, maybe the probe type in between fins?
 
the way my 96 z28 is setup is that the one fan runs constant and the other is a backup if over a certain temp. of course my camaro dosnt have a mechanical fan.
 
mr.smartass said:
Mine both turn on at the same time, through the temp switch or if I cut the A/C on, they shut off at 175, I have yet to see them shutoff once they've turned on... except when I turn the key off... damn the heat.:crazy:
Click to expand...
With the sensor in the water pump, why would the temp ever drop below 175 once the engine is warmed up? Maybe if you have a 160 T-stat.
 
lak2004 said:
Yea I had to have the thermo switch replaced because the first one was faulty
Click to expand...
where did you get it replaced at?

Mine just went out. So far Oreillys said they don't have any like the jegs type and the guy at carquest sold me a temp sensor:mad:. Damn truck over heated because of that.
 
Okay so I live in Phoenix (basically the surface of the sun). And I wanna know if these things will quell 110F heat? I also plan on towing with this set up, and haul heavy loads every day. Anyone here in PHX running these?
 
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