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
Caution: 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
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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