[leonelson]

My defrost heater failed to function and consequently ice started to build up around the evaporator coils.
What I did so far is this:
First i have a Admiral top freezer type fridge. I removed the back panel and trays to access the heating element and bi metal. My defrost timer is located in the fridge with the controls. I check the timer for operating capability by turning it to the defrost mode, waited 5 minutes and it started the compressor // this timer is a 10 hr mode type. I did a resistance test on the defrost heater and it proved to approximately 4 to 5 ohms. Now this is where I am stuck >> I unplug the heater from the Bi metal and then turned the fridge to defrost mode. I took a continuity test of the plug that gos to the defrost heater. I could not get a reading, i unplug the bi metal or thermostat and tried a reading of continuity on that plug and never received a reading. The fan works OK and there is an additional female plug that is not used so I tried a continuity reading on that it has 5 wires. I selected the black and white one with that plug, and received a reading. So I do not know if my defrost heater or bi metal or timer is defunct??
Thank you for your patience>>

[PS Staff - Sheila]

Put everything back together but leave the back panel in the freezer off and try this.

Wait until the fridge is running at the normal temperature.

With the compressor running turn the timer knob until the compressor shuts off.

The defrost cycle should last 20 to 25 minutes.

If the heater comes on your heater and bi metal are fine and the timer will have to be replaced.

If the heater does not come on check the bi metal to see if you have continuity.

If there is no continuity replace the bi metal.

The heater is about a 650 watts and you should have a reading of about 20 ohms.

If you don't get reading around 20 ohms replace the heater.

If the timer does not advance of the defrost cycle you will have to turn the knob until the compressor start back up.

Can you please verify your model number as I can't locate it in our database.

[leonelson]

thank you for your reply yes the model number seems to be located in Canada through whirlpool but you are right for I have tried too locate in the US but it did not show. I have the part numbers for all three identities from whirlpool ca // the model number is Admiral Top freezer AFT4200
I will order the necessary parts but i have switch the defrost timer through its cycle it really only takes about 5 to 7 minutes too turn the compressor on.
And within the cycle I tried a continuity test of the Bi Metal with no reading and only received approx 4 to 5 ohms on the heater

Too continue> I re tested my Defrost Heater/ by removing the element and configuring so it would plug in a normal receptacle/ seems OK it started too heat up without losing heat etc. So I have made an order for the Bi Metal and timer>>
Leo