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CharleyC · 06-28-2021, 03:45 PM

I have a 2001 Bounder 31W.
the exhaust fan above the stove has a resistor that opens the outer vent door.
the resistor is bad and there is no label saying how many ohms it is.
the ceramic resistor is aprox. 7/8" long and 5/16 square.

can anybody help with this?
vent - power range hood bounder pw part number 197286
( from quick reference list)

Arch Hoagland · 06-28-2021, 09:30 PM

here is a color code for resistors and I know it by heart. Does the resistor have colored bands on it and, if so, what are they?

KF5UMC · 06-29-2021, 02:36 AM

No color codes on ceramic style resistors only on carbon ones. Surprised there is no numbers on it. Look for a model number manufacture on the hood and then find a parts list that shows the resistor.

MrMark52 · 06-29-2021, 04:35 AM

Yeah it’s probably a wire wound resistor as opposed to a carbon resistor, so no bands.

Any more info on the hood? Is there a schematic for the circuit?

I’ve never seen a powered vent hood damper for an RV so can’t visualize the need for a wire wound resistor, unless they were using the resistor in series with the fan motor as a heater to heat a bi-metal that opens the damper door.

I would really like to see electrically or mechanically how the resistor is used - from that we can probably get an idea of what it’s resistance is.

CharleyC · 06-29-2021, 09:28 AM

attached is the photo{s} of the label on the shroud.
it looks like the attached upside down label, lower corner reads
TP WLC CC0431-04
the resistor may control the hood fan speed for low.
when powered, the vent door opens
the high speed runs, and no low speed.

also attached is the resistor,
it looks like the label is missing where the cut out
thank you for your response

MrMark52 · 06-29-2021, 02:10 PM

OK - the resistor being in series with the motor to attain a 2nd speed makes more sense. It’s the air flow from the fan that then opens the damper.

Problem with using a resistor is that it has to dissipate a lot of heat (signs of which can be seen in that resistor).

It would be a lot easier to buy a cheap PWM DC power supply and hide up inside the shroud. It has a speed control on it that you set it at a speed you like (and the motor can get started at that setting), and forget it.

Look for “DZS Elec 10A 12V-40V DC Motor Speed Controller 12V 24V PWM Variable Speed Regulator Governor Switch CCMHCN With Speed Control Knob”from Amazon

You mount it up inside the hood by first removing the knob and nut off the potentiometer, drilling a hole the size of the threaded shaft on the potentiometer in the fan shroud, connecting the wires from the switch low speed to the the power input, then hook the fan wires to the output of the control.
Once the control is wired, stick the potentiometer through the shroud, then install the nut and knob.
Hit the Low switch On and turn the knob speed control to make the fan run the speed you want.
Your done! One final check, turn the Low switch off, let the fan stop turning, then turn it on again to make sure the fan starts. If it doesn’t, set the speed a little higher.
And it may be that you have to first switch the fan on using High, then quickly switch to Low.

KF5UMC · 06-30-2021, 02:52 AM

Good idea on Pulse Width Modulation DC controller...for the resistor

See this link
https://ventline.com/i/u/6148923/f/R...oods_11-11.pdf

Resistor shows up on 2 hoods with same part number L7318-00. They don't show the value but try contacting the manufacturer. www.ventline.com n 574-848-4491

John

CharleyC · 06-30-2021, 12:08 PM

I did contact the ventline manf and they responded with the information needed:
10 Ohm, 10 Watt, Ceramic Wire-wound Resistor

Resistance Tolerance: ± 5%

Operating Temperature: -55°C to +275°C

Needs to be Fireproof

now I am searching for where to buy it.

thank you all for your help and input

MrMark52 · 06-30-2021, 12:14 PM

Digi-Key or Mouser Electronics.

But in the end, the PWM control will probably cost less, and for certain will not waste energy like the resistor will.