How To Repair Tumble dryers

Along with the growing trend towards automatic washing machines away from twin tubs, there is an increased demand for tumble dryers. A tumble dryer is often purchased as a twin to an automatic washing machine; many manufacturers market the items as a matching pair and provide a stacking kit as an optional extra to enable the dryer to stand on top of the washing machine. This saves a considerable amount of space in your laundry area.

Apart from their obvious drying action, most modern tumble dryers are equipped to cool the clothing at the end of the drying cycle; this helps stop creasing and allows you to remove the clothes easily.

Dryer components

The usual features of a modern tumble dryer are a two-heat setting control and a clockwork timer which includes a cooling period as mentioned above. With all dryers it is very important to keep air circulating over the dryer heating element(s) clear and free from the dust and fluff which normally accumulates over a period of time. The filter, which collects lint and fluff, should be cleaned every week by removing the circular disc and peeling off the coating of fine, dry lint.

One type blows air through its heater and into the drying drum; another has a motor fan which sucks air through the front of the drum and over its heating elements. In the latter case, the air is passed through the drum and filter and ejected through a vent at the front, top or rear of the machine. For most machines you can buy a flexible hose which fits over the vent to eject the warm, moist air away from the room to the outside through a window or through a permanent outlet in an outside wall. The belt-driven revolving drum is powered by an electric motor; the fan may also be belt-driven on some models.

Element cut-out

Tumble dryer heating elements have thermal overload cut-out units (TOCs) positioned close by; these are designed to prevent the element overheating when in use and to provide a constant drying temperature. One model has an auxiliary cut-out fitted in addition to the TOC; if the drum temperature rises above a safe working limit, it will stop the machine.

Rear element

One type has its heating element and TOC mounted on the rear panel; this is convenient for servicing and repair work, since access is easy. Front element Another type has the heating elements mounted above and below the door; the TOC is also fitted here. The spiral elements are fitted on the inside of the heat shield and are spaced with porcelain insulators.

Timer

Most machines are fitted with a clockwork timer switch; this usually gives a I2-minute cold tumble before stopping.

Heater switch This is a simple rocker action switch which usually provides two-heat selection from the element(s) by means of a thermostat.

Bearing strip

This strip is located on the lip of the drum inside the machine; it is lubricated with a heatproof silicone PTFE fluid and usually consists of a braided tape glued onto the lip. If the tape runs dry, it could cause a rumbling noise as the dryer operates; see below for the necessary repairs.

Dryer repairs

Regularly check the condition of the filter, belts and drum. The drum should swing freely; lightly grease its bearings to ensure it does. You can oil the door hinges lightly, but not too much since any component behind or above the door could be affected. Any belts fitted should be correctly in line with their pulleys; they should not be overstretched or cracked. The jockey pulley (found on dryers which have one belt for the drum and one for the fan) should have spring tension; a little light oil on the wheel spindle will keep it free. Don’t forget to put a drop of oil on the wheels; if the machine is on the floor and you have not fitted a venting kit, you may have to move it to an airy position before you use it.

Warning

If you are in any doubt about carrying out repairs on your tumble dryer. Refer to the manufacturer or call in a recognized service agent.

Replacing belts

The belt used to drive the drum – and the fan as well on some machines — is made of elasticated material. The cabinet will probably have to be removed if you need to replace the belt which drives the drum. Take out the lower front panel screws, lift the panel off and remove the screws from the rear of the cabinet. Undo the screws from the front of the cabinet, some of which you will find behind the door and others on the lower panel.

Pull the bottom sides of the cabinet slightly out of position and lift them upwards; take care not to scrape the drum. Undo the screws in the back panel, remove it and release the belt from the jockey pulley. Slacken the clamp around the fan and slide the fan assembly off the motor shaft. Take out the nuts from the tie rod (remembering to note their positions for reassembly) and unscrew the nut which secures the drum shaft through the ball race bearing. Remove the nuts and bolts holding the side struts to the machine from the back panel, hold the tub in position with one hand and pull slightly on the back panel with the other; this should create enough space to slide the old belt out and the new one in. Always fit replacement belts as recommended by the manufacturer. Reverse the procedure for reassembly.

Another type of dryer has separate fan and drum belts. To replace the fan belt, which is elasticated, remove the back panel and substitute the belts. The drum belt on this type of dryer is more complicated to replace. Remove the back panel and fan belt and disconnect the drum belt from the tensioning jockey pulley; you can make access to this part easier by removing the cover on the base of the dryer. The base cover is held in place with plastic rivets in two pieces; prise the centre out first and then the outer portion. The base cover can now be removed. The next step is to remove the volute assembly. This is a metal plate upon which the fan assembly is mounted; the fan itself is held with screws. Before you remove the volute, hold the drum in a horizontal position so the front bearing face is not disturbed. Holding the drum in one hand, slip off the old belt and slide on the new one; slide the volute assembly back on and secure the parts you have removed.

Removing drum

Should you need to remove the drum because the bearings are worn, the procedure is similar to replacing belts. You will have to remove the lid since the drum must be lifted out through the top of the dryer. The front bearing felts often become worn; this is indicated by a rumbling noise from the front of the dryer. Bearing felts have now been superseded by plastic bearings which are fitted on the heat shield assembly of modern tumble dryers; you can adapt your machine to accept plastic bearings. Two front and two rear bearings, clips and an instruction sheet are available in the form of a kit for this purpose.

Replacing timer

If the dryer does not stop at the end of its cycle, the timer switch is faulty and you will have to replace it. On one model you remove the lid of the dryer, pull off the timer knob and remove two screws which hold the switch to the cabinet. Carefully note the wiring connections and fit the replacement timer, reversing the procedure for removing the faulty one.

Another model also requires the removal of the cabinet before you can replace the timer; lift off the top of the dryer, pull off the knob and remove the two screws and washers. Be careful not to drop these spacer washers or screws into the body of the dryer; change over the wires and fit the replacement timer.

Replacing cut-out

If your dryer is fitted with an auxiliary cut-out which fails, it will usually stop the feed to the heater; it is a preset unit and you will have to replace it. Two screws hold the unit in position; simply push the leads over the correct terminals of the replacement.

The thermal cut-out (TOC) is working constantly and it is therefore likely it will need replacement at some time. If it fails, there will be a total lack of heat when the dryer is operating; the contacts of the TOC soften and a gap forms between them which prevents power reaching the heater. The TOC is usually secured to the heater with two screws; loosen the unit and detach the leads. Be careful not to damage the TOC as you do this, since it is a complete item; if you break one of the spirals, you will have to buy a new element. Remember to replace the sealing compound round the edges of the TOC unit since this prevents air leaks.

Replacing heater switch

This is held in position with spring clips; by squeezing the clips you can withdraw the switch from the front of the dryer. Make a note of the wiring and replace the new switch in the reverse order of removal. On some models, you have to remove the top of the dryer; the leads are replaced in the same way and the switch is also mounted on fixing lugs.

Renewing front bearing strip

If the front bearing strip runs dry of lubricant, this could cause a rumbling noise when the machine is working. To replace this strip you have to remove the drum; if you remove the cabinet and strut, you will have enough room to lift the drum carefully out. You may need to spring out the front and rear cabinet panels slightly to do this. Strip off the old adhesive after removing the tape; if you leave a lump of adhesive, a knock may develop. Make sure you replace the recommended braided tape or strip and check it is soaked with silicone PTFE fluid; this is heatproof and also acts as a lubricant.

23. May 2011 by admin
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