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Appliantology Newsletter: Special Weapons and Tactics in Appliance Repair
Special Weapons and Tactics in Appliance Repair
October 19, 2012
Special Weapons and Tactics in Appliance Repair
All Master Appliantologists acquire advanced repair katas during their years of hand-to-machine combat with malfunctioning appliances. Examples of how some of these Special Weapons and Tactics are used in appliance repair include:
– diagnosing elusive or subtle problems
– gaining insight into the condition of a component and assessing its likelihood of future or imminent failure
– testing specialized components to see whether they’re good or bad
– facilitating or implementing a particular repair
In this special issue of Appliantology, I’ll reveal some of my personal, favorite SWATs that I use on some service calls which can also be useful for amateur appliantologists working on their own appliances.
The Hand-Held Steamer
Good for all kinds of household tasks such as cleaning and disinfecting, the mighty hand-held steamer is indispensable for some appliance repairs. For example, defrosting a frosted-up evaporator coil or clearing a clogged condensate drain in a refrigerator. In fact, since I’ve been using my steamer, I can’t imagine doing these types of repairs without it! It’s makes quick work of these messy jobs.
Take a look at the icy mess in the freezer in this video; this repair would have taken over two hours without a steamer but, with the steamer, I did this entire repair in less than an hour!
You can buy the very same steamer I used in the video at Amazon for $15 less than what I paid for it! http://amzn.to/OPggAo
Refrigerator Temperature Data Logger
Sometimes I run into situations where I need a way to log temperature data inside a refrigerator for at least 24 hours to get a clear picture of what’s going on inside that box. A couple of examples are:
1. Customer complains of warm temperatures in the beer compartment of her Maytag side-by-side refrigerator but says that the freezer compartment is fine (and we know how accurate customer temperature measurements are… NOT!). You arrive and measure the freezer temperature using your infrared temperature gun and get readings that vary from +5F to +12F. Marginal temperatures for a freezer but was that because it was just coming out of a defrost or off-cycle? Was the door recently opened just before you got there? You don’t know, and all you have is the one data point: the measurement you just made. Wouldn’t it help your diagnosis if you could put a data logger inside the freezer for a day or so and then look at a graph of the actual temperature measurements inside that freezer over time?
2. Customer complains that the freezer temperature in her GE built-in refrigerator fluctuates over time from 5F to 10F to 20F and then back to hard freeze. You maybe even verified this yourself (if you spent enough time there to do this). But how much time in a typical service call day do you have to babysit freezer temperatures? And you still wouldn’t be able to gather enough temperature-time data points to discern whether or not there’s a pattern to the fluctuations which could then be correlated to some other process in the refrigerator (defrost cycles, compressor cycles, etc.). Even seeing that there is no pattern, that the fluctuations are random, is also helpful because it could indicate something as simple as the door not being closed all the way (hinge adjustment issue?).
In cases like these, you just gotta be able to look at the temperature inside the compartment over an extended period of time. Enter the Supco LT2 LOGiT Dual Channel Temperature Data Logger. Here’s a video of me showing you how to set up and use the data logger:
and you’ll need this software kit to get the data to your Windows PC, also available at Amazon: http://amzn.to/S3bmhb
Special Meter Technique for Testing a Microwave Oven High Voltage Rectifier
You probably know how to use a multimeter to make simple electrical measurements, like voltage and resistance. (If not, then see this page at my blog for a simple tutorial on using a multimeter: http://fixitnow.com/wp/2004/12/18/appliance-repair-revelation-making-basic-electrical-measurements/ ) But sometimes, you have to do a voltage test in an unusual way to check whether a component is good or bad. A common example of this is testing the high voltage rectifier (also called a diode) in a microwave oven. This is an inexpensive, common-fail part that will stop the microwave from heating if it breaks.
For most rectifiers, you test ’em by simply measuring the resistance and then switching the leads and checking it again– should read open (high resistance) in one direction and closed (low resistance) in the other. But microwave high voltage rectifiers are a special case because their internal resistance is so high that you’ll just read open in both directions and you can’t tell whether it’s good or bad that way. So, to test them, you have to actually do a voltage test using a 9 volt battery. This esoteric kata is fully revealed in this video:
The Mega-Ohm Meter (or “Megger”)
One of the common failures with a refrigerator compressor is that the varnish insulation on the motor windings starts to break down and then begins leaking current to ground. If the current leakage is large enough, you can deduce that this is happening by measuring compressor current draw– an abnormally high reading combined with the compressor running hotter than normal are sure signs that the insulation on the compressor motor windings is breaking down and the compressor is not long for this world.
Or you could directly test the compressor motor windings using an instrument called a mega-ohm meter, or “megger,” to directly test the integrity of the winding insulation. I use an inexpensive megger that cost less than $100 (back when I bought it a million years ago– it’s not much more than that now). This video shows using a megger to check the compressor motor:
You can buy the updated version of the Supco megger that I used in the video at Amazon: http://amzn.to/R8LDGd
The Clamp-On Amp Meter
Measuring current flow through a circuit or component is a powerful troubleshooting tool to have in your appliance repair SWAT bag.
For example, on a Bosch dishwasher that’s not heating, a quick current measurement a few minutes into the cycle will tell you whether or not current is flowing through the heater. If not, yet the control board is supplying 120 volts to the heater circuit, then you know the problem lies in the heating circuit itself because something in that circuit (heater, NTC, etc.) is open, stopping current flow.
Other times, the only way you can tell whether or not a part is bad is by measuring the current flow throughout that part. For example, the ignitor in a gas oven glows but the bake burner never fires up: is it a bad gas valve? Bad ignitor? Flip a coin and guess? No need to guess if you can make a simple current measurement. (Note that an ignitor can glow and still be bad– in fact, this is the most common case.) This video shows you how:
I prefer Fluke meters and I own two Fluke amp meters. Here’s the Amazon link to the one shown in the video, the Fluke T5, which is well under $100: http://amzn.to/Rd5pPh
And I also own the Fluke 322 which is a little more expensive (still under $100) but also more versatile: http://amzn.to/RIsQPf
You can find whatever appliance part you need through the parts search box at Appliantology.org:
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