Variable Speed Evaporator Fan Motor Testing for KitchenAid Built-in Refrigerators

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Ever wonder what voltages you should be getting at that Variable Speed DC Evaporator.  Well here you go. 

Variable-Speed-Evaporator-Fan-Motor

Run the Diagnostic test and check for proper operation of the evaporator fan motor if it fails proceed to step 3. 

To enter the diagnostics mode:
• Press and hold the Water Filter Reset keypad, and then immediately press and hold the Power keypad. Continue to press both keypads for 3 seconds, or until you
hear a beep.
To advance the diagnostics sequence:
• To advance to the next step in the sequence, press and hold the Water Filter Reset key for 2 seconds, or until you hear a beep. The Diagnostics Chart shows the step number and the component being tested in each step.

Step Component Tested Result* Comment
1 FreezerThermistor 1, 2, 3 Normal, Open, Shorted
2 Refrigerator Thermistor 1, 2, 3 Normal, Open, Shorted
3 Evaporator Fan Motor 1, 2 On Good Speed, On Bad Speed
4 Condenser Fan Motor 1 On
5 Compressor 1, 2 On, Off waiting on 7 minute delay
6 Air Door 1 Fully open.**
7 Bimetal/Defrost Heater 1, 2 Energized, bimetal closed, Bimetal open***

Press the “Water Filter Reset” to exit diagnostics.

* Shown on the Water Filter Indicator display.

** The air door will close at step 01, and reset to the correct opening after exiting diagnostics.

*** The bimetal may be bypassed with an insulated jumper.

NOTE: During the evaporator fan motor operation, 5 to 17 volts DC will be present at the yellow and white wires. A constant 12 volts at the red and white wires will be present anytime the fan motor is operating. The remaining steps will allow you to check the resistance of the evaporator fan motor.

2. Unplug the refrigerator or disconnect the power.

3. Disconnect the wire connector going to the evaporator fan motor.

4. Set the ohmmeter to the R x 10K scale.

5. Touch the ohmmeter test probes to pins 1 and 4 of the evaporator fan motor connector. The meter should indicate approximately 1400 to 1700 Ω.

Here is that helpful little strip wiring diagram. Read this post to learn more about wiring diagrams.

image

 

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Modular Icemaker Diagnostics

MODULAR ICE MAKER TEST

There are two types of ice makers, those in which all of the parts can be individually replaced and those in which some of the parts are clustered together into a control module. To determine which model you have remove the outer face plate. If there is knob, pull it off first, then pry off the face plate with a small screwdriver.

A modular unit will have several holes in the module, each marked with a letter (similar to the one pictured below). These holes are for test probes. If there are no holes then the ice maker is a component model and the components can be tested individually.

In this section we will test the ejector motor, thermostat and mold heater.

Testing should be done with the power off, the shutoff arm in the down, "on" position and the ejector blades in the "start" position. The position of the blades will vary among ice makers, but the start position is always with the blades over (not in) the ice mold tray. If the ejector blades are in the mold, it will not be possible to properly test the control module. Furthermore, if the blades are in the mold area, then they did not complete their cycle, and may suggest a failure of the modular unit.

A modular ice maker’s thermostat can be tested and replaced individually.

How to Test the Thermostat

Test the thermostat for continuity using a multi-meter set to the ohms setting X1. Start by testing the thermostat when it is cold (10 degrees). Insert one probe into the hole labeled "T" and the other probe into the hole labeled "H". The meter should indicate zero resistance (continuity). After the ice maker has warmed up, repeat the test and this time the meter should indicate infiinity (no continuity).

If the thermostat does not pass both tests, it should be replaced

How to Test the Motor

clip_image003Caution: Conduct this test with the refrigerator unplugged. Test the control module motor for continuity using a multi-meter. Set the multi-meter to the ohms setting X1. Place one probe into the hole labeled "M" and the other probe into the hole labeled "L". The multi-meter should show continuity, with resistance possibly as high as 10,000 ohms.

If the motor does not pass this test, you will probably need to replace the control module.

How To Test the Mold Heater

clip_image003[1]Caution: Conduct this test with the refrigerator unplugged. Test the control module heater for resistance using a multi-meter. Set the multi-meter to the ohms setting X1. Place one probe into the hole labeled "H" and the other probe into the hole labeled "L". The multi-meter should read in the range of 60 to 90 ohms.

If the heater does not pass this test, replace the ice mold heater.

How to Test the Ice Maker Water Fill Level

Icemakers are set to fill for X seconds regardless of actual water flow, and the volume of water required is specified in cc’s.
If your icemaker is producing small cubes, hollow cubes, huge cubes, or a solid slab of ice, one of the first things you want to check is the fill level. And it’s not as difficult as you might think. Unplug the refrigerator, pull the icemaker – usually one screw underneath, either 2 more or hooks above the cube mold – and unplug it. Take it to your sink and melt out any cubes with hot water. Then plug it and the refrigerator, back in, leaving it unattached from the freezer wall.
Manually start a ‘harvest cycle’ (see below) and hold a bottle under the fill tube. You’ll have to wait a few minutes, because the water enters near the end of one complete rotation of the cube ejector, which constitutes a ‘harvest cycle’. Regardless your type of icemaker, you’re looking for 130-150 cc’s, with most working best around 145cc’s, but anywhere in this range should work OK.

(When replacing your icemaker with a new one, always check and adjust the water fill level this way too. You’ll save yourself a lot of trouble.)
Manually starting a ‘harvest’ cycle:
Out of the two more common basic designs of domestic icemakers,
analog are most common.

Pop the front cover off yours and check the large gear front & center. If the front plate is metal, and you see a Phillips screw in the center of this gear, that’s great – you own a ‘microswitch’ design. This is one of the most reliable units ever made! Here’s what it looks like with the front cover off:

To manually start a cycle, either grasp the ejector and rotate upward (CW fr. front), or use a screwdriver to turn the smaller gear (CCW) if yours has a slot for this. Once you turn it a short distance, you’ll hear a little ‘click and the unit will start to run. Make sure the ice-sensing bail has clearance to raise & lower during this test cycle.
If there’s no screw, that’s OK too, you own a ‘modular’ unit, and even though we, make more income from those, they’re still pretty decent. Here’s what a modular looks like with the front cover off:

To start a cycle with this one, don’t attempt to turn the gears manually! You’ll need a short piece of insulated solid copper wire, 12-14 gauge. (Just strip a 4 in. piece out of some 12-2 ‘romex’ used in house wiring.) Strip the ends back about ¾ in. and bend it into a ‘U’ shape. This wire is inserted into the holes marked ‘T’ and ‘H’ in the front of the icemaker to bypass the thermostat and run a cycle. (don’t insert it into any holes except ‘T’ & ‘H’ !) Remove the jumper after a few seconds (or the heater will stay on), and let it run, waiting for the fill at the end. Again, make sure the ice-sensing bail has clearance to raise & lower during your test cycle.
Note: I stress this jumper wire needs to be insulated, because you’re briefly jumping 120V here. The usual precautions apply.
Both icemaker styles have a small screw to adjust water levels. The modular type has very little adjustment available, just one complete turn to both sides, though, which means the other components in the water supply have to be right (saddle valve installed properly – not to bottom of pipe, etc – clean fill valve screen, etc.) Just rerun a test cycle after each adjustment.

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Adaptive Defrost Controls (ADC) Part 4 – Maytag Refrigerators Trouble Shooting and Diagnosing ADC’s

MAYTAG, JENN-AIR, ADMIRAL, MAGIC CHEF

Maximum defrost cycle time is approximately 23 minutes.

The ADC adjusts the next defrost interval (time until the next defrost cycle) based on how long the defrost heater was energized during the last defrost cycle. The length of the defrost cycle is determined by the terminating thermostat. Logically, then, the shorter the defrost cycle, the less frost needed to be melted, so the longer the compressor can be run until the next defrost cycle.

To initiate defrost, find the ADC board. In Maytag-built machines, it is inside the temperature control housing, which also contains the food compartment (cold control) and freezer controls.

The ADC board should have six terminals: DEF HTR, COMP, L2, DEF TSTAT, TEST and L1.

Make sure the compressor is running. If you try to initiate defrost without the compressor running, it will cycle through the test mode in two seconds, and there will not be any current draw through the defrost heater.

Use a jumper wire to short between L1 and test for a few seconds. This will place the unit into a 23-minute defrost mode. The defrost heater will heat up. If you have an ammeter, the heater will be drawing about 4 to 5 amps.

If the above procedure caused the heater to heat up, the ADC board is probably bad; replace it.

If the defrost heater does not energize, test the defrost heater and terminating thermostat.

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Adaptive Defrost Controls (ADC) Part 3 – General Electric Refrigerators

GENERAL ELECTRIC / HOTPOINT / RCA
including PROFILE, ETERNA and SELECT models

Trouble Shooting and Diagnosing ADC’s

These machines use a very complex "control board" accessible at the right rear of the refrigerator. In addition to defrost functions, this board gets inputs from thermistors and controls the operation of fans, damper doors and heaters throughout the refrigerator, as well as water-in-door, icemaker, ice crusher and auger functions.

Thermistors are simply variable resistors. The resistance of a thermistor varies inversely with the temperature of the thermistor; the lower the temperature, the higher the resistance. Thus a thermistor can measure the temperature in a space and translate that into an electrical signal that a logic board can use.

For example, if the temperature in a space gets too low, the thermistor will tell the logic board, and the logic board can close an air damper to warm the space a little.

Defrost intervals (time between defrost cycles) are controlled by the frequency and duration of freezer and fresh food door openings, defrost heater runtime and compressor runtime.

Maximum defrost cycle time is 45 minutes.

Minimum time between defrost cycles is 8 hours. (accumulated compressor runtime)

Maximum time between defrost cycles is 60 hours. (accumulated compressor runtime)

If the refrigerator is not defrosting, because of the complexity of the control system, there could be a number of reasons

Thermistor Values

           Temp F            Temp C             ohms
              -40               -40            166.8
              -31               -35            120.5
              -22               -30              88
              -13               -25              65
               -4               -20             48.4
                5               -15             36.4
               14               -10             27.6
               23                -5              21
               32                 0             16.3
               41                 5             12.7
               50                10              10
               59                15              7.8
               68                20              6.2
               77                25               5
               86                30               4
               95                35              3.2

Test the defrost heater and terminating thermostat as follows: unplug the fridge, and unplug the blue connector from the control board. Using an ammeter, test the resistance between the blue wire on the blue connector, and the orange wire (pin 9, the last pin) on the J7 connector (this connector is marked N on the board, for "Neutral.") You should see 22 Ohms of resistance. You are testing through the defrost heater and terminating thermostat, so if you get either an open reading or no resistance, one of these components is bad. When you reinstall the blue connector and turn the power back on, the defrost heater should heat up. If not, the terminating thermostat is bad.

There are two thermistors in the evaporator compartment, near the top of the evap. They are a control thermistor and a high-temp thermistor, which basically does the same thing as the terminating thermostat. You can test these thermistors according to the table above. However, it is easier to just replace one or both of them. (They are both the same thermistor.)

If the heater, thermostat and thermistors test out OK, replace the main board.

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Two Ice Machines – Two problems

Two Scotsman Ice Machines, both with the same trouble reported, both had different problems.  The first ice machine had been repaired numerous times but had never worked properly.  The second ice machine just recently quit performing up to expectations.  So the trouble reported on both of the units was very slow ice production.  I’ll start off by saying that ice machines are nice to have under certain circumstances, but, when you put one in your house you are putting a commercial appliance in a residential application.  You should be prepared to have them serviced on a regular basis.  This means more often when they just break, a appliance repair is not the same as preventative service. 

Both of these ice machines had not been cared for properly.  Both of the condenser coils were packed with lint and dust, both were dirty and had partially clogged spinners.  All of which alone can cause low ice production.  After cleaning both of the ice machines and getting them in the proper condition to run, I needed to find out what else was causing the issues, because it was very slow production.  The first ice machine that had not worked properly in years was making very small irregular shaped cubes.  The way that this unit makes ice is by spraying (re-circulating) water onto a cold mold and it slowly freezes.  The pump pumps water through jet bases, through spinners and out of the jet caps.  The water comes out in a nice even spray pattern onto the evaporator mold.  In this case the cap and spinners were starting to wear down, when the water wears down the edges it makes the holes bigger than normal, thus causing and irregular spray pattern.  This is what the customer called for. But, along with making irregular cubes, the ice was melting prematurely, this was from something else that is very rare.  Upon inspecting the foam insulated cavity (storage bin) I found out that it was saturated with water.  When the insulation gets wet form the unit sweating it looses it’s r-Value.  That’s why the unit had always seemed to not keep up in production, but in combination with the worn caps and dirty condenser, it became a real problem. 

The second ice machine had similar problem, it needed new caps and spinners.  But, it also had more problems leading the customer to call us.  After getting it to make the proper size cubes it seemed to just take a 3 times the amount of time to make ice as it should.  It freezes the re-circulating water with refrigerated heat removal, after inspecting and ruling out the sealed system I had to find out what was actually causing the slow production.  Remember that it removes the heat from the same water by re-circulating it over the mold.  So I drained the water tank at the lowest point, now it has only air to freeze, after letting it run for about five minutes it hadn’t cycled yet, but instead it had water in the tank again and was spraying a full water pattern.  It turned out to have a bad water valve, it wasn’t seating properly and continued to let in fresh water, so it couldn’t properly freeze the existing water do to the fresh water constantly coming in.  This is actually very common, but it was very easy to figure out because it was letting in a lot of water, sometimes it can be difficult to find because it cane be a slow leak by the valve, or even a periodic leak. 

In this case the customer expected both of the unit to have the same problem because to him they were doing the same thing, but in reality they had totally different problems.

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Adaptive Defrost Controls (ADC) Part 2 – Frigidaire Refrigerators

GIBSON, TAPPAN, KELVINATOR, and WHITE-WESTINGHOUSE

Trouble Shooting and Diagnosing ADC’s.

On the initial plugin, or when power is restored to the fridge after a power outage:

If terminating thermostat is open, the fridge enters a compressor (cooling) cycle.

If the terminating thermostat is closed, the first defrost cycle occurs 1 hour

after initial plug-in.

Maximum defrost cycle time is 24 minutes.

Minimum time between defrost cycles is 6 hours. (compressor runtime)

Maximum normal clock time between defrost cycles is 12 hours.

Maximum time between defrost cycles (in "vacation" mode) is 72 hours.

Vacation mode is not entered unless the door has not been opened in at least 24 hours.

Note that the ADC will only enter the defrost mode if the terminating thermostat is closed. If the terminating thermostat is open when defrost is initiated, the ADC board will wait for six minutes and then return to the cooling mode.

ASSUMING that the fridge has been on and running,

and the terminating thermostat is closed,

defrost is initiated by pressing the door (light) switch

at least five times within six seconds.

The defrost heater should start heating up within 8 seconds.

If the above procedure caused the heater to heat up, the ADC board is probably bad; replace it.

If the defrost heater does not heat up, test the defrost heater, terminating thermostat and cold control for continuity as follows:

Unplug the fridge from the wall. Unplug the ADC board from its connector.

Test the connector for continuity between the following leads:

Defrost Heater = DEF TERM (blue) to DEF OUT (brown).

Terminating Thermostat = DEF TERM (blue) to NEUTRAL (lt blue).

Cold Control = COLD CONTROL (orange) to L1 (black).

Replace the defective component.

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Adaptive Defrost Controls (ADC): Part 1 – Whirlpool / Kenmore Refrigerators

Trouble Shooting and Diagnosing Whirlpool ADC’s.

Maximum defrost cycle time is 21 minutes.

First defrost is 6 hours after initial plugin (cumulative compressor runtime.)

Minimum time between defrost cycles is 8 hours.

Maximum time between defrost cycles is 100 hours.

The ADC adjusts the defrost interval according to compressor runtime, and length of the last defrost cycle.

ASSUMING that the fridge has been on and running,

and the terminating thermostat is closed,

defrost is initiated in most models by turning the cold control on and off as follows:

OFF for 15 seconds, then ON for 5 seconds, then

OFF for 15 seconds, then ON for 5 seconds, then

OFF for 15 seconds, then ON for 5 seconds, then turn the cold control off.

The defrost heater should start heating up within 8 seconds.

To terminate defrost, unplug the fridge.

Note that the ADC will only enter the defrost mode if the terminating thermostat is closed. You will hear a click as the relay on the ADC board switches from the "cool" mode to the "defrost" mode. If the terminating thermostat is open, you will hear a second click and the fridge will return to the cooling mode; you probably have a bad terminating thermostat.

If the defrost heater does not come on at all, try initiating defrost as follows:

Unplug the fridge for 30 seconds.

While it is unplugged, turn the cold control off.

Then plug the fridge back in.

The defrost heater should start heating up within 8 seconds.

The ADC board relay will also click as described above.

If the above procedure caused the heater to heat up, the ADC board is probably bad; replace it.

If the defrost heater does not heat up, test the defrost heater and terminating thermostat. You can test them for continuity together, without opening up the evaporator. Find the test plug in the wiring harness with a brown lead and a pink lead (inside the control box.) Unplug the fridge and disconnect the ADC, then test for continuity between this

brown lead and any white lead. You are measuring resistance through the heater; you should see some resistance, and some continuity. If not, the heater is bad.

Now test between the brown and pink leads. You are now testing continuity through the terminating thermostat. If the evaporator has been running and the terminating thermostat is cold, you should see continuity. If not, the terminating thermostat is bad.

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Whirlpool Refrigerator leaking water?

Refrigerator leaking This customer called the manufacturer to see who they recommended for service after four trip from the servicing appliance dealer.  It was a Whirlpool Refrigerator Model # KSRV22FHBT01, the trouble reported was a periodic leak, only a small puddle of water once every couple of days.  After searching the obvious I started to fumble with the Drain Pan.  All of the sudden the corner of it lifted away from the rest.  So the periodic leak turned out to be from the defrost drain pan.  This customer is a single woman with an automatic defrost controlled refrigerator.  So the refrigerator only had to defrost about once every two days.  I can understand how the other Appliance Professional didn’t find the problem.  By just looking at the drain pan it looked fine.  But after touching it, it came apart.  I was happy to find the problem with little trouble, a service call like this can sometimes turn into a trouble shooting night-mere, because it’s a periodic problem.

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KitchenAid Refrigerator burn marks

I was called out to this refrigerator (Kitchen Aid Model KSSC42QTS00) due the mullion being scorched (burnt) along the outside.  This well over a  $5,000 refrigerator, so this was very unattractive.  This is a simple fix even though I’m never satisfied with the results.  I would expect the engineers to come up with something a little more impressive for the repair, none-the-less, it’s a simple fix.  But there is another root cause to the problem which must be fixed as well.  There is normally a small amount of heat generated along the mullion in order to prevent the appliance from sweating like a cold glass of water does.  On older refrigerators this was controlled by an energy saving switch and a low voltage heater.  Due to energy efficiency they are now incorporating the the heat removal (refrigeration) techniques into the process.  This is done by using the hot gas lines off of the condenser and running them through the mullion to warm it up.  If a customer neglects cleaning there condenser coils this can cause excessive heat build up which can cause the scorching to occur, this is usually the case.  But, other times a faulty part is responsible.  This leads me to look at what is involved in the heat removal process, in this case it was a defective condenser fan motor.  Now that the cause of the problem is solved, the cosmetic damage can be fixed.  The involves a mullion repair kit from whirlpool.  This consists of a thick white tape that wraps around the plastic mullion to hide the discoloration, it is only tape and does not look as good as I would expect.  But at this time it’s all that is recommended by the appliance manufacturer. 

Burnt Refrigerator mullion

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