Author Topic: Replacing defrost timer in a fridge  (Read 2475 times)

FLBiker

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Replacing defrost timer in a fridge
« on: May 01, 2017, 08:51:40 AM »
My fridge has been making a buzzing / fluttering / ticking noise for the last couple of weeks.  I thought it was a fan, but the location (top center of fridge compartment) has led me to suspect that it's the defrost timer.  Fridge is a 10+ yo Hotpoint.

1) Does this diagnosis sound plausible?

I took it apart and googled the part number.  I found it at SearsPartsDirect for $48 dollars.  I also found it at McCombs Supply (https://www.mccombssupply.com/) for $8.  They get good reviews as a google merchant.

2) Anyone have experience with McCombs?

3) If the replacement part from McCombs is garbage, am I risking any serious damage to my fridge?

Thanks!

sokoloff

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Re: Replacing defrost timer in a fridge
« Reply #1 on: May 01, 2017, 02:45:03 PM »
Do you have an ice maker? That's a common ice maker sound (and can be normal).

Your defrost timer is more likely to be in the fridge compartment or under the lower kickplate than in the freezer compartment. (No particular technical reason; just the way it seems to be done.)

You can check the operation of your defrost timer before replacing. Google / youtube search your specific model number (often found on a sticker on the door). In general, the timer will serve to cycle between (most commonly) energizing the refrigeration circuit and (less commonly, typically on a 15-ish minute cycle) energizing the defrost thermostat and heater. The defrost thermostat then ensures that the heater doesn't excessively heat the freezer area, but rather just enough to defrost the coils in the 15 minute cycle.

If you have the timer in your hand (not connected to the fridge) and want to test it:
1. Check for continuity across two of the terminals.
2. Turn the timer until you hear a click.
3. Verify that you no longer have continuity across those two and instead have continuity across two other ones.
4. Turn it more until you hear another click.
5. Make sure it's like in step 1.

Then, if you want, you can make a jumper wire that will simulate the "refrigeration on" setting on the timer and run the fridge. If the noise goes away, it was probably the timer. If the noise remains, it's obviously not the timer... ;)

There is no real risk of damage to the fridge, but the timer does control power to the refrigeration and to the defrosting, so it can "break" the function of the fridge (until you replace it with a good part). In general, I've had excellent results from buying whatever part is cheapest, searching by part number. Many fridge parts are very common across many lines and model numbers.

Edit: Sorry, I originally read that the noise was in the freezer compartment. So, ignore the bit about the location advice; you obviously know where the timer is...
« Last Edit: May 01, 2017, 02:51:17 PM by sokoloff »

FLBiker

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Re: Replacing defrost timer in a fridge
« Reply #2 on: May 02, 2017, 07:21:46 AM »
Excellent, thanks!

No, I don't have an icemaker.  And we've had this fridge since we bought our house 5 years ago, so I know the noise is new.

I've ordered the replacement part (from McCombs), so I'll probably just replace it and see if that works.  I might test it, but from the noise I'm hearing, my suspicion is that the timing mechanism is the problem (as in it's getting stuck / clicking irregularly).  Thus, to me, it might still work if I manually switch it between the settings, but the timer itself might still be broken.  Does that make sense, or am I misunderstanding how it works?

Thanks again.

sokoloff

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Re: Replacing defrost timer in a fridge
« Reply #3 on: May 02, 2017, 10:15:30 PM »
I think you're on the right track. For $8 and the part already on the way, I'd install it for sure without further testing.

Manguy888

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Re: Replacing defrost timer in a fridge
« Reply #4 on: May 03, 2017, 11:04:07 AM »
Please follow up and let us know how it goes - I just fixed my fridge this weekend (evap. fan) and am interested in learning more about how all of this stuff works.

FLBiker

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Re: Replacing defrost timer in a fridge
« Reply #5 on: May 10, 2017, 07:13:46 PM »
I'm happy to report that the $8 part did the job.  The freezer is still defrosting (which it was always doing) but there is no fluttering / buzzing sound.  My wife says that she thinks the freezer is working a little better, too, but I'm not sure.

And it was an extremely easy installation.  I had to take out two screws, remove a panel, and swap the parts.  I watched a Youtube video just to be safe, but it was dead easy.