Electrical Connections

[ecotourist]

I'm trying to get our range hood fan to work less erratically. It has push button switches - on/off, faster and slower. There are 3 speeds. The LED shows each speed exactly as instructed, but the fan may or may not come on at the indicated speeds. I'm pulling the various electrical connections and cleaning each one with "Tech Accessories - Tuner Control Cleaner and Lubricant".

One friend suggests I put a little dielectric grease on the respective pins before reconnecting them. Another says just reconnect them dry.

What do you recommend - apply dielectric grease or reconnect them dry?

 

[billt460]

I think a bit of dielectric grease would help. And it would aid in preventing any further corrosion. Range hoods are subject to a lot of steam and condensation.

 

[Lubener]

I'm trying to get our range hood fan to work less erratically. It has push button switches - on/off, faster and slower. There are 3 speeds. The LED shows each speed exactly as instructed, but the fan may or may not come on at the indicated speeds. I'm pulling the various electrical connections and cleaning each one with "Tech Accessories - Tuner Control Cleaner and Lubricant".

One friend suggests I put a little dielectric grease on the respective pins before reconnecting them. Another says just reconnect them dry.

What do you recommend - apply dielectric grease or reconnect them dry?

I doubt the dielectric grease will help your issue. It may make the issue worse. Dielectric grease does not conduct electricity and its presence within any connector may prevent the circuit from functioning at all. If actual application of tuner cleaner into the push button switches, then working the switches does not resolve your problem, the switches are likely worn out or damaged.

 

[ka9mnx]

No. Think of what goes through a fan hood...grease.

 

[mk378]

Start with does the motor spin freely? If the motor is binding up it will have inconsistent speed or not start.

 

[supton]

I don’t think the grease will hurt-but I don’t think it will help. I would look first for a cracked solder joint, followed by a badly crimped wire.

 

[Bailes1992]

Sounds like an ideal location for Stabilant 22.

 

[ecotourist]

The switches correctly control the LED read out. The motors (2 of them) run fine at all 3 speeds when they agree to run. If the motors start at some speed they will run at that speed as long as the switch is left on. But sometimes (often actually) they won't start.

For what it's worth they seem to start more frequently when switched to the low or high speed. Getting them started at some speed doesn't seem to have any effect on whether they will run at another speed.

Sure sounds like a poor connection somewhere.

And there are a number of very tight bends in the wires so @supton 's suggestion of a badly crimped wire is also possible. Our range hood is 30" wide and there is an otherwise identical 36" model. The entire switch assembly (no longer available) is identical for both sizes probably accounting for the too long wiring. https://www.jennairreplacementparts.com/PartDetail/Switch/49001295/1185755

 

[eljefino]

The motor's worn out and gunked up.

Same think happens with bathroom fans, they fill up with hairspray and dander and seize.

 

[Pablo]

The motor's worn out and gunked up.

Same think happens with bathroom fans, they fill up with hairspray and dander and seize.

I was thinking this as well. If connections and controls are solid, it's the motor

 

[ecotourist]

The motor's worn out and gunked up.

Same think happens with bathroom fans, they fill up with hairspray and dander and seize.

If the motors are worn out or gunked up why do they (two fans two motors) run fine if the get started? They certainly aren't seized.

I could take the motors out and clean them but it wouldn't be easy. So I'd want a high probability of a good outcome. The squirrel cage fans aren't "clean" but look quite good - way better than every bathroom fan I've taken down whether running or not.

 

[fantastic]

If the motors are worn out or gunked up why do they (two fans two motors) run fine if the get started? They certainly aren't seized.

I could take the motors out and clean them but it wouldn't be easy. So I'd want a high probability of a good outcome. The squirrel cage fans aren't "clean" but look quite good - way better than every bathroom fan I've taken down whether running or not.

Your motor is having a hard time "Starting" & that's also the time the motor demands the most amperage. This is one sign the motor is getting "weak". If you've cleaned the connections & double checked wiring then it's the motor but always replace the switch if replacing the motor. Also, just for double checking get a new switch, & hook it up, to see if the contacts may be worn.

 

[ecotourist]

Can't get a new switch. Parts are all unavailable. Too bad because it's a very good unit. It's an older Jenn-Air and similar models cost in the range of $2000. So it's worth a lot of effort.

I've cleaned all the connections I can get apart. I couldn't get a few connections apart so I squirted cleaner into them and moved the parts around. I haven't found anything that looks burnt.

There are 2 large capacitors. They look fine. Their connections have been cleaned.

An update: The motors now start and run fine on all speeds. But it did something like that yesterday too. As I left it plugged in, it eventually stopped working. I'm going to leave it plugged in (potentially for a day or two) to make sure it keeps working.

Taking the motor and fan assemblies out would not be easy. I would have to drill out a row of pop rivets (and of course replace them to put it back together). I could do that too if I have to.

So you ask, "Why not just buy a new Braun (or similar) range hood?" A reasonable one would only cost a few hundred dollars. I could do that too but the space is beautifully set up for this particular unit in custom cabinets. And taking the fittings apart (made especially for mounting this unit) might leave a mess. And it's a very nice looking unit that works very well - when it works.

Fingers crossed.

 

[TheLastWord]

QUOTE: "There are 2 large capacitors. They look fine. Their connections have been cleaned."

Can not judge by appearance. How old? Do you have a DMM with capacitance ability?

But 2 motors and 2 caps is impressive for a quality unit. Jenn Air does make good stuff.

Take safety precautions.

 

[ecotourist]

QUOTE: "There are 2 large capacitors. They look fine. Their connections have been cleaned."

Can not judge by appearance. How old? Do you have a DMM with capacitance ability?

But that is a good sign for a quality unit. Jenn Air does make good stuff.

Take safety precautions.

I have an analog multi-meter. It has the usual Volts (to 600 and 1200 Volts DC), Amps & Ohms. I don't know how to assess a capacitor electronically.

Here's what it says on the capacitors:

Ducati energia​

16.27.0929​

12.5 uF +/-5%​

330V 10000 h/cl. B​

-25/85/21 p2​

CE​

S 50/06​

EN 60252-1​

They're big units, 2 metal cylinders each about 1" diameter X 2" or 2 1/2" long. (They're now back in their 2" X 2" X 8" plastic box).

The range hood (which was made in Italy) is possibly 20 years old. I doubt that any components have ever been replaced.

I know that capacitors can be dangerous. I left the range hood unplugged for a day before touching them. And only took one connection off to clean it at a time.

 

[ecotourist]

@TheLastWord I've been looking at the Ducati energia website. It looks like their capacitors are designed to deform (push out one end) when they fail. There was no sign of any deformation with these 2.

 

[oldgrayman]

@TheLastWord I've been looking at the Ducati energia website. It looks like their capacitors are designed to deform (push out one end) when they fail. There was no sign of any deformation with these 2.

If they open circuit they won't deform .

 

[ecotourist]

Update:

There is still something wrong. As it has warmed up, the fans (both of them) still work on speeds #1 and #3, but no longer on #2.

Both motor and fan units seem to be working just fine on all 3 speeds (when they're working).

The switch should be okay too. There is no #2 speed control per se (as the controls are actually just on/off, faster, and slower) and everything works correctly except when the fan should be running on #2. It won't start on #2, slow down from #3 to #2, or speed up from #1 to #2. But the LED always reports the instruction accurately - including when it should be on #2.

Going to check out the capacitors tomorrow. Maybe one of them is blown. After +/- 20 years in service they're both well past their 10,000 hours of rated service.

 

[Pablo]

Maybe I missed it, but how is the fan speed actually controlled?

 

[ecotourist]

Maybe I missed it, but how is the fan speed actually controlled?

There are 5 push buttons and a LED. One button is for lights, one is for a timer and 3 are for the fan.

There is an on/off button which is supposed to start the fan at the middle (#2) speed. There is a (+) button. And there is a (-) button. With these 3 buttons you can access all 3 speeds.

As noted above everything is currently working correctly except when the fan should be running on #2. When you push the "on" button it hardly ever starts (it should start on #2), though it will run correctly on #1 or #3. The fan stops when you try to go from #3 to #2, or from #1 to #2. The LED always displays the instruction correctly - it's just that the fan (usually) doesn't come on when the LED is displaying #2.

I believe the push button controls are working correctly. The instruction for the fan are always displayed correctly by the LED, but when the instruction is speed #2, the instruction is either not getting through to the fan motors or it's not being implemented.

The 2 motor and fan assemblies do run on all three speeds (though not often at the middle #2 speed).