Tikkabik

So the repairman from Sears showed promptly this morning a few minutes past 8 AM to fix our fridge. I'm about $200 poorer for the experience, which is still less than half the cost of a new fridge, and we get to keep our ice maker and the other amenities this model offers that our "spare" backup one -- still at the other house -- doesn't. He gave the refrigerator a clean bill of health otherwise, and said that it should continue to last years.

It turns out the defrost circuit was shot, which, as you may recall, was one of the things I thought might be wrong. Not a common problem, the tech told me, but not exactly unheard of either. He figured it out by trying to manually trigger the defrost circuit. No joy -- it didn't turn on at all. So the circuitry that handles that function needed to be replaced.

Refrigerators work on a really simple concept: Convection. Heat causes air to circulate; warm air rises. Today's run-of-the-mill refrigerators typically have a refrigeration coil in their freezer compartments that chills the air to sub-zero temperatures; fans then blow cool air into the refrigeration compartments. Warm air naturally rises, goes over the condensor to cool, and is blown back down into the fridge. The freezer is the coolest spot in the fridge, because it's closest to the condensor.

Frost free refrigerators -- virtually all fridges available these days -- cycle a small amount of heat to those coils every few hours to keep frost from forming. The cycle period varies from model to model -- usually it's anywhere from four to eight hours. The defrost circuit causes the frost to turn to water, which then drips off the coils and runs into a drain through a channelled gutter in the back of the freezer, usually hidden behind a panel or underneath a tray.

The water drains into a drip tray underneath the fridge, and a fan above the tray typically evaporates this drip as soon as it forms, so you don't find puddles of water under your fridge after a few days.

When the defrost circuit doesn't work, the frost builds up, typically over a period of a few days or a week or so. This is what was happening. Eventually the frost gets so thick it blocks the air from going over the coils. This causes the fridge to warm up, because it can't do anything with that warmer air -- that gets trapped in the refrigerator compartment, driving the temperature up. This is consistent with what we were seeing: The fridge would warm up first, then eventually the freezer would start having problems with temperature regulation.

90 plus degree days and kids opening the fridge door to look for drinks and snacks all day long certainly don't help matters much. But the good news is the gaskets around the fridge door and freezer door both look soft and pliant and unbroken.

I had to manually defrost the fridge again yesterday morning, while Bonnie was at a doctor's appointment -- the fridge was heating up, and I didn't want the food to go bad. That got rid of a one-inch thick layer of frost that had accumulated on the back of the freezer compartment and a lot of frost that had condensed on the coils at the bottom of that panel, visible when you remove the bottom tray on the freezer. It was enough to fill up the drip tray twice, although I knew there was still more. I just didn't want to risk any more food spoilage than I had to.

The repairman took off a panel in the back of the freezer to show me the condenser and coils, which I knew were there but hadn't actually seen before -- the coils were still caked with ice, though they were free enough for air to circulate again. He did the rest of the job as he replaced the defrost circuit.

We'll know in the next few days if that does the trick, but I'm confident it should. Hopefully it's the last frickin' fridge story I'll have for a while.