My dryer drum is rotating and the heater is working, but condensation is building up in the drum instead of dispersing. No matter how long the cycle, the clothes don't dry. I've checked the filter, vent and outlet pipe, and they're clear. Any ideas, please?

It sounds like the drain is blocked with lint or mold gel.

check the exhaust tube externally and internally for excess lint build-up on the sides. You may not have the vent obstructed, but you may have the venting restricted. Clean out lint if there is excess. It may need a good scraping/ brushing to help your machine breathe. Just an extra thought.

if your heater coil is working

dryers have a cool down cycle built in

the coil heats shuts down
and drum rotates till end of cycle

First check to see that the exhaust venting line is clear (not full of lint) as well as the path in the dryer to the line. This is the most common cause of no heat.
Second set the knob to heat turn on dryer with the lights off and the door open but the "open door" switch so that it still rotates with the door open. Look at the back of the rotating drum for a orange/red glow behind the drum (the heater coils). If there is no glow the heater coils are probably broken.
As the dryers age, the amount of thermal cycles the heater elements go through until the point when the coil wire breaks. There usually two heater coils behind the rotating drum (one hotter than the other and when combined the hottest heat temperature setting. You will need to pop open the top where you see the belt that turns the drum. The belt is removed from the spring loaded tensioner pulley at the base of the dryer. Then you can lift the drum out to get to the heater coils. Since no heat, both should be broken and will require replacement.

First check to see that the exhaust venting line is clear (not full of lint) as well as the path in the dryer to the line. This is the most common cause of no heat.
Second set the knob to heat turn on dryer with the lights off and the door open but the "open door" switch so that it still rotates with the door open. Look at the back of the rotating drum for a orange/red glow behind the drum (the heater coils). If there is no glow the heater coils are probably broken.
As the dryers age, the amount of thermal cycles the heater elements go through until the point when the coil wire breaks. There usually two heater coils behind the rotating drum (one hotter than the other and when combined the hottest heat temperature setting. You will need to pop open the top where you see the belt that turns the drum. The belt is removed from the spring loaded tensioner pulley at the base of the dryer. Then you can lift the drum out to get to the heater coils. Since no heat, both should be broken and will require replacement.

It sounds as though the fan motor is faulty, usually these motors distribute the heat from the heater box into the drum. Because the heater box is getting hot I doubt if the fault is the thermostat so it may well be the motor or associated wiring

Might be a limit or a the heater element.MY REPAIR PAGE

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Check the "Bias thermostat" for continuity with a multimeter. IF it is bad, replace with this part.

Go to http://fisherpaykelparts.net/techhelp/fisher-paykel-top-load-dryers-us-models/ Check posts on "Heaters" in this forum will work you through your problem

check the temperature switches in the back for continuity and also the moisture sensor on the exhaust housing at the rear of the unit. all these switches should be normally closed.
good luck...jay