[kyx]

About a week ago, we realized that the refrigerator wasn't cold enough and took a look at our freezer and saw that there were ice that was building up. So, we surfed the net to see what the problem was and that's probably due to a defrostation problem.

Had a look at the thermostat and it seemed fine.
Took out the defrost heater and took a look, it didn't look fine. we don't have a multimeter to test the heater and thermostat.

called up a parts shop and they said that the defrost heater part for our Maytag model has been discontinued but that they have a defrost heater that works universally for most fridges. we bought that and fixed the new defrost heater in.

The fridge keeps running and only stopped once for around 20 minutes.

How would we know if the heater will work ? What if the defrost thermostat isn't in good working order, will that somehow affect the heater ?

Please advise.

Thank you

[denman]

Here are your parts
Replacement parts for MAYTAG PTB1821ARW REF - TOP MOUNT | AppliancePartsPros.com

How would we know if the heater will work ?

First remove the evaporator cover in the freezer so you can see the heater.
Do not let them de-ice.

Manually force a defrost cycle by turning the defrost timer cam (Item 2 in Section 2) till the fans and compressor turn off.
There is usually a hole in the cover to allow you to do this.
Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
Note: That you may still have a defrost problem if the timer is stalling during it's rotation so is never getting into a defrost cycle.

If the heater is not on.
Unplug the unit.
Remove the wire for one side of the heating element from the wiring and measure it for continuity, usually around 20 ohms or so.

If the heater is OK
Remove one wire to the defrost thermostat and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.

What if the defrost thermostat isn't in good working order, will that somehow affect the heater ?
Yes it will.
If it never closes then you will not get a defrost as it kills power to the heater.
If it does not open just above freezing then the heater will say on too long during defrost.