Aux Fan Timer

[DancinCampers]

Well, I have been thinking of adding a timer to run my aux condenser fans after I stop, to help in keeping the area under the doghouse from heating up so much. Today I finally installed one. We are leaving next week for the summer, so will be able to report on whether it makes a difference or not.

I bought a 15 min timer from Home Depot & a 30amp 12volt relay from Radio Shack.

Here is what it looks like before install:



The timer controls the relay coil. I tapped my 12v power from the chassis fuse box, Aux Circuit B. The power from the relay goes to a tap on the red wire for the fans before it splits into a Y to feed both fans.

I mounted it behind the front cap on a steel support with a large zip tie, where it does not get direct airflow thru the grill. Hopefully this will keep it from getting wet. I can reach it thru the bottom grill opening to turn it on.

[DancinCampers]

Well, I have been thinking of adding a timer to run my aux condenser fans after I stop, to help in keeping the area under the doghouse from heating up so much. Today I finally installed one. We are leaving next week for the summer, so will be able to report on whether it makes a difference or not.

I bought a 15 min timer from Home Depot & a 30amp 12volt relay from Radio Shack.

Here is what it looks like before install:



The timer controls the relay coil. I tapped my 12v power from the chassis fuse box, Aux Circuit B. The power from the relay goes to a tap on the red wire for the fans before it splits into a Y to feed both fans.

I mounted it behind the front cap on a steel support with a large zip tie, where it does not get direct airflow thru the grill. Hopefully this will keep it from getting wet. I can reach it thru the bottom grill opening to turn it on.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DancinCampers:
Well, I have been thinking of adding a timer to run my aux condenser fans after I stop, to help in keeping the area under the doghouse from heating up so much. </div></BLOCKQUOTE>May I also recommend that you allow the engine to idle for about 2 to 3 minutes before shutting down the engine "after" a hard Interstate run. The water pump circulating coolant through the engine and bringing everything down to equilibrium works much better than shutting down and running the condenser fans.

I see no harm in running the condenser fans as you suggest and I hope your initiative returns the results you are attempting to achieve.

[oemtech]

Brazels should be able to add this via the ECM upgrade...

[DancinCampers]

I did have Brazel change my fan run parameters when they did the reprogramm. The tech said he programmed 2 min at above 108C.

But I don't think that program works once you turn off the engine. Maybe wrong on that.

I do run my engine for several minutes after I park, but I think this will not aleveate the heat soak that occurs in the doghouse after shutdown.

But only time will tell.

[Tom N]

IMHO, running the fans after shutting down the engine would do nothing but push more hot air from the hot radiator into the engine area.
Thus causing slower cool down of the dog house.

[Tom N]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DancinCampers:

I do run my engine for several minutes after I park, but I think this will not aleveate the heat soak that occurs in the doghouse after shutdown.

But only time will tell. </div></BLOCKQUOTE>

Why would you contiue running your engine after stopping??? Your cooling is much more effective when moving than when stopped. IMHO this would generate more heat. And, if I recall correctly Allsion recommends not doing this.

[DancinCampers]

Like I said only time will tell.

Running the fans will be equivilant to coasting downhill with the engine off. No new heat being generated, but old heat being removed. I actually think I'll remove more heat from the doghouse by cooling the exhaust manifold & headers.

I believe that running the engine for a few minutes is beneficial because the engine has heat not removed by the radiater yet. Running the engine at idle under no-load, which is generating less heat than when running at 60mph, allows the radiater to remove some of that heat before shutdown.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tom N:
Why would you continue running your engine after stopping??? Your cooling is much more effective when moving than when stopped. IMHO this would generate more heat. And, if I recall correctly Allison recommends not doing this. </div></BLOCKQUOTE>Tom, Allison recommends not to idle your engine for excessive periods of time.

Any professional truck driver has standing orders to allow their engine, turbo, and cooling system to idle down for a brief period of time before shutting down the engine. This practice assures for a heat equilibrium to be achieved before shut down and goes a long way to eliminate concentrated heat spots.

Suggesting that a heavy duty, gas powered vehicle owner allow their engine to idle for 3 minutes before shutdown after a hard run is reasonable and prudent.

[Full-Timers]

Everything I have read about what to do in the case of overheating says to pull to the side of the road and LEAVE ENGINE RUNNNG to help cooling.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Full-Timers:
Everything I have read about what to do in the case of overheating says to pull to the side of the road and LEAVE ENGINE RUNNNG to help cooling. </div></BLOCKQUOTE>.... and in the event of a real problem open the hot water valve to the dash heat because there's a core in there that will shed some heat as well.

[BEBOP]

It occurs to me that a good time to do this is when you pull off the freeway into a reststop, especially if you are climbing mountains.
Sounds like good advice to me,
thank you,
Bebop

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BEBOP:
..... when you pull off the freeway into a reststop, especially if you are climbing mountains...... </div></BLOCKQUOTE> Exactly! You're the man!

[Tom N]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> No new heat being generated, but old heat being removed. </div></BLOCKQUOTE>

True, no new heat being generated, but where does the heat go from the radiator?? Your fans are blowing it back into the dog house area.

Now if you placed a fan that blew ambient air directly into the dog house area you would cool that area.