Whirlpool fridge repair in Nairobi.

Bacteria multiply quickly above about five degrees. If the fridge side is warm, move milk, meat, fish and cooked food to the freezer or a cool box with ice, and keep the door closed as much as you can. If the freezer is still frozen, do not open it more than you need to.

As a rule of thumb, fresh meat, fish, dairy and cooked leftovers should not stay in a warm fridge for more than a few hours. Food that has thawed and warmed should not be refrozen if it has been warm for long. When in doubt, throw it out: a repair is cheaper than being ill.

Medicines that need refrigeration should be moved to a cool box and kept as cold as the label asks. If you are not sure whether something is still safe, check the instructions on the packaging or ask a pharmacist.

Many people ask for a gas refill as soon as a fridge stops cooling. In practice, a fridge uses no gas. It circulates the same sealed charge for its whole life. If the charge is low, the fridge has a leak, and a refill without finding the leak means paying again in a few weeks.

Most cooling faults are something else: a blocked air channel, a stopped fan, a dirty condenser, a failed defrost heater, a worn door seal, a start relay, a thermostat or a board. These are found with a few tests, and they are usually cheaper to put right than a gas job.

When the tests point to a leak, we find it first, usually at a joint, a pipe that has rubbed or a corroded coil, repair it, pull a vacuum to remove air and moisture and then charge the exact gas the fridge was built for, by weight. That is the only way a gas job lasts.

A freezer with thick ice works harder and holds less. If your freezer is not no-frost, defrost it when the ice is a few millimetres thick. Switch it off at the wall, empty the contents into a cool box, and open the door. Put towels underneath to catch the water.

Never use a knife, a screwdriver or any sharp tool to chip the ice. The cooling pipes run very close to the surface, and a puncture lets out the gas and ruins the freezer. A bowl of warm water placed inside speeds things up, and a hairdryer on a low setting held at a distance can help, if you keep it away from water.

Wipe the inside dry before switching on again, and give the fridge a few hours to cool before refilling it. If ice builds up again within weeks, the door seal or the defrost system needs a technician.

Cold air has to move. Pack the shelves loosely enough that air can circulate, and never block the vents at the back or on the ceiling of the compartment. Keep the bulky items on the shelves and leave the door bins for things that tolerate warmth.

Raw meat and fish belong on the lowest shelf in sealed containers, so they cannot drip onto other food. Dairy and cooked food go in the middle. Fruit and vegetables belong in the drawers, where the humidity is higher.

Let hot food cool to room temperature before putting it in. Hot pots warm the fridge, force the compressor to work and bring in moisture that turns into frost. Cover liquids, because uncovered liquids add moisture to the air.

The condenser coil releases the heat the fridge removes from the food. On older fridges it is a grille on the back; on newer ones it may be a coil under the fridge behind a kick plate. Dust and kitchen grease form a blanket on it, which traps the heat.

Unplug the fridge before you start. Use a soft brush or the brush attachment of a vacuum cleaner to lift the dust, then a damp cloth for grease. Clean the area around the compressor too, and remove dust from the fan if there is one. Do it every few months, or more often in a dusty kitchen.

A clean coil can make a noticeable difference in how long the compressor runs and how much power the fridge uses. It is one of the cheapest and most effective bits of maintenance you can do yourself.