Appliance Terms Dictionary, words starting with 'D'

Dave's Dictionary of Appliance Terms
The 'D' page

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Damp dry – With the advent of Permanent Press fabrics, this is a term not seen much any more. This was a dryer setting that left some moisture in the laundry, allowing for ironing (shudder!)

Defrost drain – a trough under a refrigerator’s evaporator coil, with a tube connected to carry the coil’s melted frost to the drain pan under the refrigerator, where condenser and compressor heat evaporates it.

Defrost heater – An electric heater in or under the freezer evaporator coil. This heater is turned on regularly to melt off accumulated frost so air can pass freely though the coil, giving up heat.

Defrost limit thermostat – a small bimetal thermostat (‘thermodisc’) that’s usually electrically in series with the defrost heater. Calibrated to open and turn off the heater when the coil temperature has been raised enough to ensure the coil is clear of frost. Several common temperature ratings are 45, 50, 60, and even 70 degrees F. Newer ones are rated in Celcius – you’ll usually find this rating stamped on the device. Inexpensive generic versions are readily available, and can be ‘bugged’ to the many different original harness plugs used. Wire nuts with a bit of silicone added for waterproofing work well for this.

Defrost timer – a very reliable, clock-driven switch (commonly being replaced with less reliable ADC circuit boards today) that is responsible for turning a refrigerator’s compressor off and its defrost heater on after a set amount of time. Usually wired to run along with the compressor and initiate a defrost after x hours of accumulated compressor run time. A common timer ‘trips’ into defrost after 8 hours, and has a defrost cycle of around 20 minutes (note, though, that the heater probably won’t be on for the full 21 minutes. In most cases, the defrost limiter will turn the heater off before the timer does.

Dehumidification – removal of moisture, humidity, primarily from room air in our usage here.

Dehumidifier rating – These machines are rated in pints/24 hours, or how many pints of water they’ll remove from the air in one 24 hour period.

Desiccant – any one of several chemicals, usually in crystal form, that are used to absorb and hold unwanted moisture. Most commonly found in refrigeration system drier filters to absorb moisture that would cause problems if allowed to circulate.

Detergent dispenser – Dishwasher or clothes washer mechanism that releases detergent into the wash load at the proper time(s). Operated by bimetal, wax motor, solenoid, and timer mechanical linkages.

Door gasket, or seal – Rubber or vinyl strips are used to seal the door openings on refrigerators, dryers, and dishwashers. Fiberglass and metal mesh material is used on oven doors. Refrigerator gaskets have flexible magnetic strips inside that ‘stick’ to steel cabinets and hold doors closed, while allowing them to be opened easily, preventing child entrapment.

Door hinge – Probably needs no explanation, there are many types of these, but all support and allow a door to swing open and closed. Many refrigerator door hinge assemblies have built in ‘automatic’ closers, usually simple cam systems, that ensure closure to keep warm air entry to a minimum.

Door latch – By US law, these can no longer used on refrigerators due to the child entrapment danger. Various styles are used on dryers, microwave ovens, dishwashers, and front load washers, which include a lock that prevents door opening while there’s water in the machine.

Door liner – The inner panel of an appliance door, referring mainly to refrigerators, upright freezers, and dishwashers.

Door lock – Latch or lock mechanism that prevents door opening. Commonly used in food freezers (keyed, manual), front load washers (and some top loaders lock during spin) and ovens (electrical, lock in 900F clean cycle).

Door reversal – This used to refer only to refrigerator doors, but these days many front load washer and dryer doors can be reversed too (a great idea!). Most refrigerator doors can be switched to swing in the opposite direction, and this has been a really great idea. Extra hardware is rarely needed for this job – existing hinges, screws, and handles are made so they can easily be moved over and used on the cabinet’s opposite side.

Door seal (see door gasket)

Door shelf end cap – This is the little plastic piece that latches into a refrigerator or freezer door liner, and to which the shelf rails attach.

Door shelf rail – the rail, usually metal, that prevents items on refrigerator and freezer door liner shelves from falling off.

Door spring – Used to counterbalance a door to keep it from falling heavily, these springs do a lot of work, and breakage is pretty common. Most doors use a pair of these, and it’s best to replace both of them when either breaks. But when it’s really hard to locate a replacement, a new hook can, in most cases, be bent back onto the broken one (that’s what usually breaks). Ovens, dishwashers, and drop-down dryer doors all use these.

Door switch (also see lid switch) – ‘Makes’ or breaks a circuit when a door’s open or closed. Used on dryers to prevent running with the door open and burning out an element, or worse. Turns refrigerator interior light(s) and fans on and off – and on newer ADC systems, ‘tells’ the computer how often the door is opened. Prevents your dishwasher from spraying you with hot water when its door’s opened. Opening and closing the oven door hits this switch, turns on interior lights and lets the EOC (electronic oven control) know whether it can latch the door to clean, and whether it should allow a broil cycle, etc.

Drain check valve (see also drain loop)– Dishwashers use one of these to help prevent drain ‘gray water’ from finding its way back into the machine. Most are just a simple rubber flapper valve, but they do their job effectively. Still need a high loop or air gap in the line, though.

Drain heat exchanger – This is what I call the 6” hooked piece of 12 gauge copper wire that I hang over defrost heaters. This wire extends down a refrigerator’s drain and transfers some of the heat from the defrost heater, preventing drain freeze up.

Drain hose – Connects an appliance to the house drain. Used in clothes washers, dishwashers, and dehumidifiers, to get rid of ‘gray water’.

Drain impeller (see impeller) – Usually refers to a dishwasher’s pump impeller, responsible for pumping water out of the machine (as opposed to its wash impeller, which recirculates wash water and does most of the actual cleaning work).

Drain loop – 1) The detail most commonly left out of dishwasher installations. A machine’s drain line should be tied up as high as possible under the kitchen cabinets before connecting to the house drain, or connected to an ‘air gap’ (which see). This prevents sink gray water from migrating into the dishwasher. Also, if the drain runs down through the floor before connecting to the house drain, the wash water’s siphoning out is a sure thing unless a loop or air gap is used. 2) Refrigerator defrost drains often use a loop too. This loop, or trap, keeps warm air from entering the cabinet.

Drain pan – Most commonly referring to the pan underneath refrigerators, this pan collects defrost water. The water evaporates from this pan, which needs occasional cleaning, but not emptying in normal use.

Drain pump – Newer clothes washers and dishwashers use a separate pump/motor assembly to drain their water.

Drain trap – A loop in a drain line, designed to hold a small amount of liquid, to prevent the movement of unwanted gases through the drain (refrigerator drain traps keep warm air out of the food compartment; house drain traps keep sewer gases out of the living area).

Drain trough – A funnel shaped trough located under the evaporator coil of self-defrosting refrigeration systems. Catches defrost water from the coil, and directs it through a connected tube and into the drain pan, where it evaporates.

Drain tube – The small hose that connects the drain trough to the drain pan. Often runs through Styrofoam dividers, where its drain water can freeze and clog with ice, causing problems.

Drier filter – a small torpedo-shaped refrigeration system component, usually located between the condenser coil outlet and the capillary tube. Filled with desiccant, often silica gel, this very important device also has a fine screen in its outlet. Responsible for catching impurities and moisture, keeping the system clean and dry. Should be replaced whenever a system is opened for service.

Drip pan – usually refers to the pans, or bowls, under range surface units and under some gas burners. Catches spills.

Drive block – Washer component, usually aluminum, that mounts the tub to the spin shaft.

Drive coupler (also see 'coupler') – Newer washers made by Whirlpool no longer use a drive belt, but a ‘direct drive’ coupler between the motor and transmission, to transfer power. Made of two plastic pieces with a rubber drive cushion between them.

Drum seal – Clothes dryers use seals, usually made of felt, to seal the gaps where the rotating drum mates to the rear bulkhead and cabinet front. Some seals are attached to the drum, others to the cabinet, but all service the same purpose – prevention of air intake through this gap. Air leakage here causes air bypass around the heating element or gas burner. In electric dryers, this causes premature thermal fuse and/or heating element failure. In gas machines, thermal fuse problems as well as fires can result.

Drum support – as the name suggests, this is a bearing surface that supports the weight of a dryer drum and its load of laundry. Rollers and various types of plastic slides are used to do this. Years ago, these were rollers using ball bearings and lasted for many, many years.

Drum vane – the ‘paddle(s)’ mounted to the inside of the drum of dryers and front-load washers. These do the work of moving the laundry through a dryer’s airflow or a washer’s water/detergent solution.

Dual-action agitator – the term coined for top load washer agitators with a top half that moves somewhat independently of the bottom half. Most of these incorporate a ratcheting auger that rotates in only one direction, driven by the agitator’s oscillating bottom half. This system provides excellent laundry ‘turnover’ in large loads. The upper half does very little work in small loads.

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