The Stovebolt Site Forums The Shop Area The Electrical Bay Heated relay

I installed daul 11" electric fans in my "59" Apache, I ran it for the first time yesterday and the fans worked great for about 15 minutes then they stopped and i noticed the relay for the fans was super hot, the wiring is all correct, the relay and fans are brand new, Wadda Ya think?

Pappa J, two things come to mind --- 1) too much current for the relay, or 2) bad relay. I lean toward the former as starting point. If the relay was originally intended for only one fan then you may have "over-amped" it. What is the current rating on the relay? What is the sum of the current draws for both fans? Did it work again after it cooled down? jt

The fans draw 25 Amps total and the relay is rated at 30 amps, I just double checked the wiring again and it is correct. And the fans do come back on once the relay cools down. The relay turns on the fan at 180F and shuts it off at 160F
What i dont understand is the directions say to use a 180F thermostat, But if the fan turns on at 180 and the thermostat is just starting to open i will never get any water thru the radiator and thus the fans will never shut off, and they do run costintly until the relay overheats and shuts off........

Does the relay have 3 wires for the contacts? If I understand you correctly it is also a temperature sensor. Besides the common lead, if there are connections for both normally-open and normally-closed contacts then you may have it wired to the wrong contact where the fan is turning off at 180 instead of on. Just a thought. I think I'd be talking to the manufacturer next. Keep me posted.

I'll be back in a couple of days. My daughter is taking me sailing for Father's Day. jerry

Well I contacted the manufacturer (ron francis) He says i need to hook another relay up for the other fan, says one relay is handling to many amps. Thanks for your help jerry, Bon Voage!

Most relays like a lot of electrical things are rated for a peak rating and not a contunious rating. In this case of your relay it was rated for a peak load of 30 amps, so for example the surge of amp load that occurs when you turn on both fans would likely exceed 30 amps when the fans are first turned on. The contunious load of the fans is supposed to be 25 amps but things like the size of the wire used, the distance the current has to travel etc will affect the total amp load. Ideally most relays are designed to work at 70 percent of their rated capacity on a contunious basis. Also check when you go shopping for a relay, be aware that there are two kinds, the contunious duty and the intermintent ones which act like a heavy duty switch. Getting the right ones the first time will save you some social embarrasment....Thanks Randy.

Thanks randy, I think i got it right, We will soon see..............