FIXED KRFF507ESS00 Defrosting issue

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go-rebels

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The situation... note that the thermistor was in the correct location. This was after 30 minutes defrosting the outer case and some time heating the coils directly. Notice that the entire top of the evaporator was covered with ice preventing any airflow over the coils. My previous defrost attempt to melt the ice with the plastic cover in place was entirely ineffective.
43739
43740
 

go-rebels

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Note that to take off the plastic evaporator cover you MUST remove the vertical air vent that runs to the top of the frig, and to that you MUST remove the plastic ceiling. That is described here:


Don’t be afraid to pull down hard to separate the snaps.

The small water filter electrical connector is particularly difficult to separate. I needed an extra pair of hands to hold the ceiling while I pried the miniature connector lock with the tip of a pointy knife while pulling the connector apart.

The vertical air vent is snapped into the rear of the frig with 3 pairs of clips that are easily separated. Then, with the ceiling removed you’ll need to pull the left upper corner free that is slightly trapped by the ice maker housing. Once the left upper portion of the vertical air guide is free then everything comes apart easily.

20hr later my frig is at 36F and my ice maker is filled. I checked the programming and the defrost mode remains at the basic 8hr setting (not "ADC".)
 

Jake

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Not so fast.:)

Go-rebels we need the last two digits of your model number, that is extremely important for this problem.

KRFF507EWH00 or KRFF507EWH01?

Which is it?

Jake
 

Jake

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go-rebels

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The fan motor was running most of the time I was manually defrosting the coil. No problem there. And the frig cooled quickly after I put things back together.
 

go-rebels

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Correction: while I was defrosting the coils, the fan was running all the time. Obviously I don't know if the fan runs all the time.
 

guardians

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Take your time. Read the service test instructions all the way through before starting. There's nothing difficult to do. If you have any questions, just ask. I'll boil it down where we're at so far so you don't get confused. Basically your defrost cycle wasn't turning on so we're checking the defrost system components. The defrost system consists of defrost heater, defrost thermostat and the control board. The defrost thermostat (bi-metal) must be closed before the defrost heater will turn on. Test #6 will tell you if the thermostat is open or closed. It must be closed (01).

Test #7 tells you what defrost mode you're in. According to the test results your machine is set to Adaptive Defrost Control (01). The machine will start a defrost cycle after the compressor has 8 hours of run time which can take between 9 and 96 hours. Use switch #3 on the UI to change the defrost cycle from 01-ADC to 02- Basic 8 hr. The defrost cycle will start after every 8 hours. Go to test #38. The display will show OF. Use switch #3 on the UI to display Lo (long defrost). Press SW1 and SW2 simultaneously for 3 seconds (or unplug the refrigerator) to exit service mode. A defrost cycle will start immediately upon exiting service mode. There's a couple ways to check if the defrost heater is on.

1- Listen for the water drops to sizzle as they hit the defrost heater.
2- Put your hand on the back wall near the bottom and you can feel the heat from the heater.
3- Remove the back wall and actually see if the heater is on
4- Use an amp meter on one of the wires in the power cord. (2 amps or higher= heater on. Less than 1 amp =heater off)

The defrost heater is like a light bulb. It's either good or bad. If the defrost heater is on, don't order a control board yet. Changing from ADC to Basic 8 hr may have fixed it. If the heater is not on you'll need to remove the back wall and check the heater for continuity. Continuity= replace the control board. No continuity= replace the heater.

2 important points to remember-

1- If the evaporator is completely frosted over you must first defrost it and remove all the frost.
2- Remember we're working from a tech sheet for a different model and we're assuming the service tests are the same.

WP12729128 Heater
View attachment 36498

Control board in stock here: W10807590
So, add me to the list of this problem.

I made all the changes outlined here the last time I melted the ice, changes all the settings mentioned and reloated the thermostat.

so now I'm thinking heater coil. I can't seem to find it though. I removed the lower back panel, don't see it. I also removed a middle left side panel, that seems to be the circuit boards.

Can anyone post where this is?

Thanks!
 

Jake

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There is no defrost heater on the refrigerator evaporator. Just on the freezer evaporator.

We need the model number of your refrigerator, that's very important. The model number tag is located inside the refrigerator section on the upper walls or ceiling.

There have been fan motor problems in the refrigerator section on these models, THUS you get that frost build-up too if the fan does not run at all.

Here's another member that reported the same:

Here's the evaporator fan motor for the refrigerator section for model KRFF507ESS00:
W10633627 Motor-Evap


Here's the refrigerator fan motor for model number KRFF507ESS01:
W11033168 Fan Motor & Harness


Jake
 

Jake

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Ok,

Correct, there is no defrost heater on the fresh food evaporator coil, only the freezer evaporator coil has the defrost heater. This is a very complex dual evaporator cooling system with the 3-way involved.

This how it works:
If the refrigerator compartment is calling for cooling the control determines if the refrigerator evaporator coil temperature has been above a predetermined temperature (approximately 35°F) for 15 minutes. This is to assure the evaporator coil is
defrosted.
- If the evaporator coil is below the predetermined temperature the refrigerator fan turns on to circulate air over the evaporator coil to defrost it. The fan will operate until the evaporator coil is above the predetermined temperature for 15 minutes.
- If the evaporator coil is above the predetermined temperature but for less than 15 minutes the refrigerator fan turns on to circulate air over the evaporator coil to defrost it. This continues until the 15 minute time is met.
• When the evaporator coil is above the predetermined temperature for 15 minutes or more the 3 way valve moves to the closed position. At the same time the compressor, condenser fan, refrigerator evaporator fan turn on.
• With the 3 way valve still in the closed position the compressor evacuates the refrigerant from the low side of the system and pumps it into the high side of the refrigerant system.
• After a predetermined time (approximately 2 minutes) the 3 way valve changes position allowing refrigerant to flow from the high side, through a capillary tube, and into the refrigerator evaporator coil allowing cooling of the refrigerator compartment.
The refrigerator evaporator fan also turns on and circulates air across the evaporator coil. Heat is removed from the air and recirculated back to the compartment.
• When the refrigerator temperature cools below the control setting it will either:
- Turn the compressor, condenser fan, and evaporator fan off and switch the 3 way valve to the open position.
- Or, if the temperature in the freezer compartment is above the control setting or is within a predetermined amount from the cut in temperature the 3 way valve changes position allowing refrigerant to flow from the high side, through a capillary
tube, and into the freezer evaporator coil allowing the cooling of the freezer compartment. The freezer evaporator fan also turns on and circulates air across the evaporator coil. Heat is removed from the air and recirculated back to the
compartment.

So if the refrigerator evaporator fan is running, and you moved the the thermistor to the proper position, and put the control board in 8 hr defrost instead of ADC, then I really don't have a clue why it's still frosting up your refrigerator evaporator coil. Unless there is a problem with that 3-way valve sticking and allowing the refrigerator evaporator coil to get a CONSTANT flow of refrigerant through it and not closing that 3 way valve to the refrigerator evaporator after the temperature in the refrigerator has been satisfied.

I'd suggest having Whirlpool come out to see if it is that 3-way sticking open for the refrigerator evaporator coil.

I'm closing this thread as its getting too long.

Jake
 
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