Sam Brown

[Sam Brown]

The most common cause of the condensate drain clogging is when water freezes in the drain tube. As soon as a little water freezes, it will cause more water to back up, which also freezes, making the problem worse.

You usually see clogs on models that are using what’s called a “duckbill” grommet at the end of the condensate drain line. These have a tendency to stick closed, causing clogs, and will usually cause this problem repeatedly until they are with a better solution, such as a p-trap kit.

[Sam Brown]

240 VAC appliances like electric dryers can indeed run just fine on 208 VAC power supplies. No adaptation needed. Naturally, due to the lower voltage, the heating element will run a little cooler than it would on a 240 VAC circuit, but it will still do the job just fine.

As for reading 208 VAC across L1 and L2 but 120 from line to neutral, that is correct. It seems counterintuitive, but that’s the way it is. Without getting too into the weeds, it’s because, in three-phase 208 VAC power supplies, the three phases are only 120 degrees out of phase with each other. Whereas in split-phase 240 VAC power, the split phases are 180 degrees out of phase.

I’ve written a blog post about power supplies over at our tech support site, Appliantology. Check it out if you would like a little more detail: https://appliantology.org/blogs/entry/1112-know-your-power-supplies/

[Sam Brown]

The answers to the homework are in the next unit’s video. So keep plugging away!

[Sam Brown]

The reason he didn’t go into more detail in that second video was because we had already gone through that circuit pretty extensively in the first video. There are only two possible bad actors for an open neutral to the evaporator fan: the defrost heater and the defrost bimetal. Of those two, the bimetal is the far more common-fail item, and a single voltage measurement across it will tell you if it has in fact gone open.

The purpose of the second video was more to show how you can easily be tricked by an open neutral if you get complacent with your diagnostics.

[Sam Brown]

The situation you’re describing would be extremely unlikely, but yes, it is very possible that it would load down the DC power supply. That power supply is only capable of supplying a certain amount of current before the voltage that it supplies begins to diminish below useable levels.

[Sam Brown]

A below spec (or even borderline) amp measurement on an ignitor is certainly enough troubleshooting to confidently replace it. The only feasible circumstance that would cause the situation you describe would be a bad ignitor out of the box, and that’s very rare.

[Sam Brown]

Glad to help! Always feel free to ask if you have any more questions.

[Sam Brown]

On question 12 I see on the schematic that L1 supplies power to M2 on the motor.

Take another look at that. At M2, L2 passes through the centrifugal switch on its way to the heater. But it doesn’t power the motor. Line for the motor come through M4. So which line is connected to M4?

[Sam Brown]

When a switch actuates, that means it has changed from its normal state. That’s why we say

When a switch is not actuated, it is said to be in its “normal” state.

That means that “unactuated” and “normal” mean the same thing here.

So if the NO (normally open) terminal of that switch is open, and the NC (normally closed) terminal is closed, would you say the switch is actuated or unactuated?

[Sam Brown]

I’ll go through the questions one at a time.

#4: Which timer cam and contacts must be made in order for anything else in the washer to get power?

You don’t even have to look at the timer chart to see the answer for this one — though the answer is there too. If you look at the labelling on the washer schematic (make sure you’re looking at the correct schematic). Both the switch and the contacts are labelled there.

#8: Which timer contacts supply Line voltage to the dryer motor?

The answer to this is written right on the dryer’s timer chart. It’s the smaller timer chart that’s just above and to the right of the dryer schematic.

#12: The dryer motor runs off L1 and Neutral.

You’re correct that the motor doesn’t run on 240 volts. But double check which line it uses in its power supply.

[Sam Brown]

I don’t believe I sent a file via email — could you clarify what you’re referring to?

[Sam Brown]

The key is in the wording of the question:

In the timed dry cycle, what is the function of the motor centrifugal switch? (select all correct answers)

Is the neutral to the timer motor completed through the centrifugal switch in timed dry?

[Sam Brown]

Remember how voltage drop works in parallel circuits: in parallel branches, each branch will drop the full supply voltage.

With the detector switch closed, the main coil is shunted, so it drops 0 volts. There’s no current flowing through it. But the other three loads (the ignitor, booster, and safety) are all in parallel to each other, so they each drop the full 120 volts.

Let me know if it still doesn’t make sense.

[Sam Brown]

I believe in that particular video, he simply used chassis ground as a reference. However, as we often stress, ground is never what you want to use as a reference. There’s a more detailed explanation of this in the little pop quiz right below the video. Make sure to check that out!

[Sam Brown]

Which door is Scott referring to when he said to close the door which let’s the optics relay reset?

He’s referring to the freezer door. You’ll notice that, if you close the door to the compartment, it will push that flapper closed. That’s why manually pushing on the flapper emulates the door closing.

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