Question About T@B Converter Fan

Mouseketab

T@B Converter Fan.... Does it run every time it's charging the camper battery, or only when it needs cooling while charging the camper battery? (I added some circuits to my converter, and have had it off and apart for several days). I got everything connected again, and everything works, but I have yet to hear the converter fan. I am currently running lights and the 12V fridge with the trailer unplugged, and I'll give it a couple of hours. WFCO 8725P

Bayliss

@Mousketab, below are my notes regarding the converter fan (which I made after watching a WFCO troubleshooting video.)  As the notes indicate, the fan turns on when a certain (unknown to me) 12V load level is reached.  If you are not hooked up to 120V AC, and running the refrigerator and lights on DC power, I would think it would kick on.  However, you might try adding a greater 12V load (e.g., add the radio and/or TV) to see if that causes the fan to turn on.  Something you might also want to try, as indicated in the last line of my notes, is to disconnect the 12V power and plug in the 120V AC to see if that briefly kicks on the fan.  (You might want to wait a few minutes after disconnecting the 12V power, just in case there is already residual power in the circuit board capacitors.)  Finally, if none of that works, is there any possibility that you disconnected the fan while working on the WFCO?

WFCO CONVERTER FAN NOTES:  While the fan on the WFCO cools the 12V circuit board, it is load based, not temperature based.  Therefore, the fan will turn on, and remain running, as long as the converter is drawing a certain 12V load threshold.  They don't say what the load threshold is.  Thus, the fan will likely kick on, and remain on, whenever you are running a sufficient load (e.g., the water pump, turning on lights, the radio, etc.)  If the power draw (i.e., load) drops below the pre-determined threshold, the fan will turn off.  NOTE:  Even without a load, when you first plug in the trailer 120 VAC power, the fan will briefly turn on, then off (due to charging of the circuit board capacitors.)

Mouseketab

I've got a feeling, the fan got disconnected, or didn't get connected correctly. I had the converter completely out and disconnected. I've tried running down the battery some, then plugging back in, tried turning on just about every 12V thing I have, and no fan, checked all the fuses. I'm a bit too tired and sore to deal with it tonight anymore. So I will open everything back up tomorrow.

MuttonChops

@Mouseketab ,@Bayliss;
Believe the Power Center Fan will only operate above a specific 12VDC Load (current draw) when the Power Center Convertor {120VAC -to- 12VDC} circuit is operating.

The Power Center Fan will not turn-on if T@B Battery Only 12VDC is being used . . . the convertor circuit is off so no power center internal heat is being generated.

Mouseketab

Even when plugged in to shore power, converter fan is not coming on

ScottG

I find that if I plug-in to shore power then connect the battery, the fan will run for a few seconds before shutting off. It's very consistent. Might be be a good way to test if you haven't done so already.

Otherwise I rarely hear the fan run. 

JCALD

When we bought our 400 the converter fan would come on when on shore power and the battery was being charged.  After a couple of months the fan started to run very erratic going from slow to high and back to slow.  Shortly after that it quit all together.  It was replaced under warranty.  I suspect you could easily find a replacement on line from a PC parts house if you are out of warranty.

Mouseketab

Well I've done everything I can think of. Replaced all fuses, rechecked all 110 connections, let the battery lose some power overnight and plugged it all back in to charge, turned on all 12V stuff when plugged in, even took the fan out and tried it with a 9V battery. The fan worked with the 9V battery, so it's something in the circuit board that came loose. So I guess I'm getting a new converter. Which honestly is what I should have done in the first place instead of trying to save money and add circuits to the 8725. I'll get a new 8735 and wire that up. The converter is about 7-8 years old, so it's probably time.

JCALD

I really think you can just change the fan.  It is nothing more than a computer cooling fan.

Mouseketab

But the fan worked when I disconnected it from the converter, so it's not the fan itself, it is in the circuit board connecting the fan to the rest of the systems. The fan is not getting power somehow. All the 110 connections tested good, all the 12 volt connections tested good. The new converter is just over 130, The higher power converter is probably best anyway. That is what nuCamp puts in their units.

Bayliss

@MuttonChops, thank you for the input in your post.  Although that level of specificity was not included in the troubleshooting video, it makes sense.  I will update my notes to reflect your comments.

P.S.  I just found this info on the "load" issue (from WFCO web site FAQ):

Should my fan run all the time?

No. The fan is controlled by the load. The fan will start running at a low speed when you have approx. 3.0 to 6.0 DC Amp draw.  It will increase in speed as you add more load until you have approx. 14.0 to 15.0 Amps draw.  At this point, the fan is at its maximum speed and will stay there even if you add more load, should amperage drop below 3.0 to 6.0 DC amps, the fan will shut off.

ALSO, for additional info on the fan operation, watch this WFCO video:

Why does the fan on my converter run all the time?

Bayliss

@Mouseketab, for whatever value it is (maybe just for nice to know info?), I found the below information on a site discussing troubleshooting an RV converter (unfortunately, I don't know how to locate the thermostat/temperature sensor unit):

"Test the thermostat/temperature sensor unit which controls the fan by blowing heat onto the heat sink using a hair dryer or a shrink-wrap gun. Use your test meter to confirm 120-volt power is passing to the thermostat/temperature sensor unit, and then that 120-volt power is passing from it after it heats up. If it is not, the thermostat/temperature sensor unit is faulty. With the 120-volt power on, if the thermostat/temperature sensor unit is functioning and power is conveyed to the fan but it does not start up, the fan is faulty."

Mouseketab

Bayliss said:

@Mouseketab, for whatever value it is (maybe just for nice to know info?), I found the below information on a site discussing troubleshooting an RV converter (unfortunately, I don't know how to locate the thermostat/temperature sensor unit):

"Test the thermostat/temperature sensor unit which controls the fan by blowing heat onto the heat sink using a hair dryer or a shrink-wrap gun. Use your test meter to confirm 120-volt power is passing to the thermostat/temperature sensor unit, and then that 120-volt power is passing from it after it heats up. If it is not, the thermostat/temperature sensor unit is faulty. With the 120-volt power on, if the thermostat/temperature sensor unit is functioning and power is conveyed to the fan but it does not start up, the fan is faulty."

My dad suspects the same thing. He is coming by this weekend to see if we can troubleshoot this. I know the fan is not faulty, because I pulled it from the unit and tested it with a 9V battery.