How Does a Water Dispenser Work?
A water dispenser looks simple from the outside, but inside it is a small fridge and a small kettle working side by side. Here is how the water moves, how it gets cold and hot, and what each part does.
Updated 14 November 2026
The basic working principle
A top load dispenser works by gravity. You turn a 19 litre bottle upside down on the top. Water flows down into a small reservoir until it covers the bottle neck; then air cannot get in and the flow stops by itself. Each time you take a glass, the level drops, a bubble of air rises into the bottle and fresh water flows down.
From the reservoir, water goes to three places: the cold tank, the hot tank and, on 3 tap models, straight to the normal tap. A bottom load dispenser does the same job, but a small pump lifts water up from the bottle in the cabinet. More on the two styles: Top Load vs Bottom Load Water Dispenser.
How the cooling system works
Most dispensers in Pakistan use compressor cooling, the same idea as a refrigerator:
- The compressor pumps refrigerant gas, such as R134a or R600a.
- The hot gas gives off heat in the condenser grille at the back.
- The refrigerant then expands in a coil wrapped around the cold tank and soaks up heat from the water.
- A thermostat switches the compressor off when the water is cold enough.
Models like Haier HDR-TC2C1G 2-Tap Water Dispenser with Fridge list cold water at 10 degrees C or below and about 2 litres of cold water per hour. Cooling power on our models is about 90 to 110 W. That is why you must keep the back grille dusted and 10 cm away from the wall.
Is there a compressor in every water dispenser?
No. Most of the dispensers we list have compressor cooling, including Orient, PEL, Dawlance, Homage, Electrolux, Gree, Haier, Midea and Panasonic models. A few simple models, such as Canon WD-103 Turbo 3-Tap Water Dispenser and PEL Classic 115 2-Tap Table Top Water Dispenser, are not listed with compressor cooling.
Non-compressor dispensers usually cool with a small electronic (thermoelectric) chip and a fan. They are lighter and quieter but give cool rather than chilled water, and struggle in a hot Multan or Karachi summer. If cold water matters most, check the "compressor cooling" line in the specs before you buy.
How the hot water side works
The hot tank is a small steel tank with an electric heater, usually 420 to 580 W on our models. A thermostat keeps the water at about 85 to 95 degrees C and switches off when it is reached. A second safety cut-out switches the heater off if the tank runs dry or overheats; models such as Orient Velvet 3-Tap Water Dispenser with Fridge and Homage HWD-49332 3-Tap Water Dispenser with Fridge list double overheat safety.
Canon bottom load water stations, such as Canon CHA-WB-T1225-B-30 3-Tap Bottom Load Water Dispenser, add glass kettles and a 1350 W heater for boiling-hot water for tea. The hot tap has a child lock on most models, which you press or slide before water comes out.
Parts of a water dispenser and what they do
- Bottle seat and support collar: hold the bottle and pierce its cap.
- Reservoir: the small tank under the bottle.
- Cold tank: usually 2.5 to 4 litres, wrapped by the cooling coil.
- Hot tank: usually 0.8 to 2 litres, with the heater.
- Compressor, condenser and capillary tube: the cooling system.
- Thermostats: one for cold, one for hot.
- Taps: hot (red), cold (blue) and normal on 3 tap models.
- Power switches: the red and green switches at the back.
- Pump and float: on bottom load models only.
- Drip tray: catches spills.
When something goes wrong, our water dispenser repair guide explains each fault.
How a bottom load dispenser and a fridge cabinet work
In a bottom load dispenser, a suction pipe goes down into the bottle in the lower cabinet. When the reservoir level drops, a float or sensor starts the pump. An empty bottle alarm, listed on Dawlance DBD-1035 3-Tap Bottom Load Water Dispenser and Ecostar WD-500BL 3-Tap Bottom Load Water Dispenser, warns you when the bottle is done.
A dispenser with fridge has a small cooled cabinet in the bottom, typically 16 to 20 litres, cooled by the same compressor. It keeps drinks and fruit cool but is not a full refrigerator. See Water Dispenser with Fridge Price in Pakistan.
Does a water dispenser purify water?
No. A normal dispenser only cools and heats the water you put in. It does not filter it or remove germs, so use clean bottled or filtered water. The hot tank does not kill all germs either, because it does not boil the water continuously.
Keep the dispenser clean, change the bottle often and clean the tanks every few months, as shown on how to clean a water dispenser. If you want filtered water from the tap, read water dispenser vs water cooler vs filter.
Can a water dispenser work without electricity?
A top load dispenser will still give room-temperature water from its taps during a power cut, because gravity does the work. The cold water stays cool for a while in the insulated tank. A bottom load dispenser needs power for its pump, so it stops. The Dawlance DBD-1034 3-Tap Bottom Load Water Dispenser lists a 12V pump that its maker calls solar and UPS friendly.
For power numbers and running cost, see water dispenser electricity consumption.
Temperature settings and switches
On most dispensers you cannot dial an exact temperature. The cold and hot thermostats are fixed at the factory, and you only switch each side on or off with the green and red switches at the back. Switch on cold first, and switch on hot only after water flows from the hot tap, so the heater never runs dry.
Touch panel models are different. The Canon CHA-WD-3T1150GB-361 3-Tap Water Dispenser lists a sensor touch panel with a temperature display and 6 temperature settings, and the Electrolux ELWD-BP3T-DD 3-Tap Water Dispenser with Fridge has a digital display panel. More such models: Digital Touch Water Dispenser Price in Pakistan. In winter you can switch off cooling completely and save power; in summer switch off the heater.
