Whirlpool WED87HED Dryer Hi-Limit Thermostat/Inlet Thermistor Testing and Replacement

WhirlpoolWhirlpool WED87HEDDifficult⏱ 3 - 4 hours

Инструкция на английском (оригинал iFixit). Непонятные термины — в разделе «Основы → Словарь».

Use this guide to test the hi-limit thermostat/inlet thermistor on your Whirlpool Duet WED87HED Dryer and replace it if necessary. These components are combined into one unit, so if either component fails, you will need to replace the whole unit. These components control your dryer's temperature. The inlet thermistor lets the main board know what the inlet temperature is, and the hi-limit thermostat shuts off the heater if it overheats. The hi-limit will reset and allow the heating element to operate again after a cooling period. When the hi-limit fails, the dryer may not heat at all, or sometimes it will overheat until the thermal cutoff or thermal fuse operates. When the inlet thermistor fails, your machine will display an error code. This guide is rated as difficult, mainly because of the amount of disassembly required. None of the steps are particularly difficult in themselves, except perhaps removing the front lower bulkhead.

Сначала выполнить:Do these first:

🧰 Tools

5/16" Nut Driver
Phillips #2 Screwdriver
6-in-1 Screwdriver
5/16" Socket
Socket Wrench
FixMat
1/4" Nut Driver
3/16 Flat Head Screwdriver
Spudger

⚙️ Parts

Whirlpool Dryer High-Limit Thermostat & Inlet Thermistor - WP8557403

ШагиSteps

Safety Precautions

Before you begin your repair, unplug your dryer.
Your power cord may have four prongs rather than three. The additional prong is a ground connection.

Unfasten the top panel

Throughout this guide, keep track of each screw and reinstall it exactly where it came from.
Use a 5/16 inch nut driver to remove the two 15.7 mm-long screws securing the top panel to the rear panel bracket.

Remove the top panel

Grasp the top and slide it 1/2 to 1 inch toward the rear of the machine.

Step 4

Lift the top panel upward to separate it from the chassis.
Remove the top panel from the machine.

Disconnect the control panel

Disconnect the control panel cable from the main board.

Step 6

Disconnect the drum light connector.

Unfasten the control panel

Use a 1/4 inch nut driver to remove the two 16.3 mm‑long sheet metal screws located at each end of the control panel.

Remove the control panel

Lift the control panel up and tilt it away from the chassis to remove it.
Make sure to thread the cable through the hole in the chassis.
During reassembly, thread the cable through its proper hole before reinstalling the control panel.

Disconnect the door switch

Use a small flat blade screwdriver or a spudger to unlatch both sides of the door switch connector.
Unplug the connector.

Unfasten the front panel

Use a 1/4 inch nut driver to remove the three upper front panel 16.4 mm-long sheet metal screws.
Tilt the machine backwards and prop it securely, or have a friend hold it.
Use a 1/4 inch nut driver to remove the four sheet metal screws on the bottom edge of the panel:
Two 16.4 mm screws
Two 13 mm screws

Step 11

Use a Phillips driver to remove the two 15.8 mm‑long screws inside the door area below the drum opening.

Remove the front panel

The panel is heavy and awkward. You may want to have a friend help you with this step.
Pull the bottom of the panel away from the chassis about two to three inches.
Lift the front panel off the small tabs on the chassis near the top of the panel and remove it.
Make sure you don't snag the door switch wire harness as you remove the panel.

Unfasten the cover plate

Use a 5/16 inch nut driver to remove the 16.2 mm-long cover plate screw.

Remove the cover plate

Remove the cover plate.

Disconnect the cord

Mark the cables with a permanent marker if needed and take a picture or draw a diagram.
Use a Phillips driver or a 1/4 inch nut driver to remove the three 21.4 mm-long screws.
If your plug has 4 prongs, there will be a ground connection from the cord as well. Use a 5/16 inch nut driver to remove this connection.

Remove the cord

Pull the cord carefully down through the round hole.
Make sure you replace the connections correctly when you reassemble.

Unfasten the cord terminal block

Use a 5/16 inch hex driver to remove the 16.5 mm-long green ground screw.
Use a Phillips driver to remove the two 15.3 mm‑long cord terminal block screws.

Move the cord terminal block

Move the cord terminal block behind the rear panel.

Unfasten the rear panel

Use a 1/4 inch nut driver to remove the eleven rear panel screws.
Ten 20 mm-long screws
One 12.9 mm-long screw under the water inlet.
Throughout this guide, keep track of each screw and reinstall it exactly where it came from.

Step 20

Use a 1/4 inch nut driver to remove the 16.4 mm-length screw holding the main board bracket to the chassis.
Use a 1/4 inch nut driver to remove the two 20 mm-long screws from the top rear of the machine.

Remove the rear panel

Put on gloves before continuing, as the rear panel is sharp.
Lift the panel about 1/2 inch and tilt it to the rear to release it from the vent pipe.
Slide the panel off the vent pipe and remove it.

Reassembly information

During reassembly, perform the following:
Make sure that the vent pipe is fitted into the collar on the panel.
Make sure the tabs at the bottom are aligned to the bottom rim of the chassis.
Position the panel so its screw holes match with the chassis.

Remove the lint filter

Pull the lint filter up out of the lint filter slot to remove it.
These photos show the front panel in place, but the procedure is the same if the front panel is already removed.

Unfasten the lint filter housing

Use a 1/4 inch nut driver to remove the 16.4 mm‑long mounting screws securing the lint filter housing.

Remove the lint filter housing

Pull the filter housing outward from the chassis and down to remove it.

Disconnect the moisture sensor

Squeeze the locking tabs on the moisture sensor connector.
Disconnect the connector.

Disconnect the main board

Label, photograph or make a sketch of the connector locations and of the main board bracket position on your machine.
Disconnect all of the connectors on the main board front half.

Step 28

Label, photograph or make a sketch of the connector locations and of the main board bracket position on your machine.
Disconnect all the connectors from the rear half of the main board.

Unfasten the main board from the main board bracket

Use a 1/4 inch nut driver to remove the 12.8 mm‑long sheet metal screw that retains the main board to the main board bracket.

Separate the main board from the main board bracket

Lift the rear corner of the main board nearest to the side walls of the chassis.
You want to release the locking tab on the side of the main board.
Slide the main board toward the front of the dryer to release the tabs securing it to the main board bracket.

Remove the main board

Remove the main board from the main board bracket.

Remove the main board bracket

Use a 1/4 inch nut driver to unfasten the 16.4 mm‑long sheet metal screw holding the main board bracket.

Remove the wiring harness from the main board bracket

Lift off the main board bracket from the chassis and turn it so the bottom is exposed.
Using long nose or slip joint pliers, pinch the locking wings of the harness retainer clamp.
Separate the harness from the main board bracket and remove the main board bracket.

Unfasten the upper front bulkhead

Use a 1/4 inch nut driver to remove the two screws securing the upper front bulkhead to the front of the chassis.
One 16.4 mm-long sheet metal screw
One 19.8 mm-long sheet metal screw
Use a 1/4 inch nut driver to remove the two 16.5 mm‑long sheet metal screws securing the top plastic portion to the upper front bulkhead.

Remove the upper front bulkhead

Remove the upper front bulkhead and set it aside.

Release the belt tension

Take careful note of the belt path before proceeding.
Be very careful during this step! The idler arm is under spring tension and may pinch you, or it could damage the belt switch if the arm is allowed to snap down.
Push the idler arm (the metal upside-down "L") up to relieve the tension on the drive belt.
Remove the belt from the motor pulley.
Gently lower the idler arm until it rests parallel to the dryer floor.
During reassembly, refer to your notes or the belt path link to rethread the drive belt.

Unfasten the lower front bulkhead

Use a 1/4 inch nut driver to remove the four screws securing the lower front bulkhead.
Two 16.1 mm-long sheet metal screws on the left side of the lower front bulkhead.
Two 13.2 mm-long sheet metal screws on the right side of the lower front bulkhead.

Remove the lower front bulkhead

While supporting the drum, lift the lower front bulkhead off of the hooks on the chassis.

Step 39

Lower the bulkhead about 2 inches to free the drum rollers tucked under the drum.
While supporting the drum, remove the lower front bulkhead.
During reassembly, tilt the bulkhead to the right to get the rollers under the lip on the front of the drum. Once the drum is on the rollers, you can move the bulkhead to the upright position.

Remove the drum

Use the belt to lift the drum a few inches.
Swing the drum out of the front of the dryer.
Note which end of the drum faces the front.
If the belt is broken, stand in front of the drum and put your arms inside it. Lift it up and pull it through the front opening of the machine. Having someone to help you with this is a good idea.
Make sure you get your drum back on the rollers when you reinstall the lower front bulkhead. Take your time and don't force it.

Hi-limit thermostat/inlet thermistor information

The following steps show how to test and replace the hi-limit thermostat/ inlet thermistor.

Disconnect the hi-limit thermostat/inlet thermistor

Pull the spade connectors straight off to disconnect the hi-limit thermostat portion of the hi-limit thermostat/inlet thermistor.
Be sure to grip the connectors and not the wire when disconnecting.

Test the hi-limit thermostat

If you do not need to test the hi-limit thermostat, skip this step.
This step requires a multimeter. If you aren't familiar with how to use one, here is a guide that will help you.
With the hi-limit thermostat disconnected, you can check it for continuity. It should show continuity (less than 1 Ω) at room temperature.
If it shows OL or anything above 1 Ω, replace it.

Disconnect the inlet thermistor

Free the inlet thermistor connector by lifting the black locking tab with a small flathead screwdriver or spudger.
The locking tab is fragile, so only lift it a small amount to free the connector. Make sure to grasp the connector, not the wires when disconnecting them.
Once freed, pull the connector straight out to disconnect the inlet thermistor.

Unfasten the hi-limit thermostat/ inlet thermistor

Use a 1/4 inch nut driver to remove the two 12.8 mm‑long sheet metal screws securing the hi-limit thermostat/ inlet thermistor.

Remove the hi-limit thermostat/ inlet thermistor

Remove the unit by pulling it straight out from the mounting hole.
Note the orientation with the thermistor connector to the rear of the machine for reassembly.

Test the inlet thermistor

This step shows how to test the inlet thermistor. If you just need to replace the hi-limit thermostat or inlet thermistor, you can skip this step.
With the thermistor removed from the heater housing, test for resistance with the multimeter across the two small terminals.
The value shown (61.8 kΩ) is acceptable for a good thermistor at room temperature (68°F/20°C). The nominal range at this temperature is 61.2‑63.7 kΩ.
If the device shows outside this range, replace it.

To reassemble your device, follow these instructions in reverse order. Repair didn’t go as planned? Ask our Answers community for help.

«Whirlpool WED87HED Dryer Hi-Limit Thermostat/Inlet Thermistor Testing and Replacement» — автор Bill Gilbert, iFixit, лицензия CC BY-NC-SA 3.0. Показано без изменений. Открыть оригинал и комментарии →