No Hot Water in Your Apartment in Portugal? Check These 6 Things First

1. Gas: empty bottle or closed valve

If your esquentador runs on gas bottles, lift the bottle slightly. An empty one is much lighter than you expect. Swap it, reconnect the regulator firmly and open it.

If the gas is piped, find the valve on the gas pipe near the heater. The handle should be in line with the pipe (open), not across it (closed). Check that the hob works — if the hob does not light either, the problem is the gas supply, not the heater.

After swapping a bottle, air can get into the hose. It may take a few attempts before the heater lights. If it still refuses after that, see our guide to gas bottles and water heaters.

2. Ignition batteries

Many esquentadores have a battery compartment at the bottom, usually for two large D-size batteries. They power the spark that lights the burner. When they are weak, you hear clicking without ignition, or the heater lights only on some attempts.

Replace both batteries, even if only one seems weak. It costs a few euros and solves more breakdowns than any other single fix.

3. Water flow and pressure

An esquentador only switches on above a minimum flow of water. If the tap is only half open, if cold water pressure is low in the whole flat, or if the shower head is blocked with limescale, the heater may not detect enough flow to start.

Open the hot tap fully. Try the kitchen tap as well as the shower. If one tap works and another does not, the problem is in that tap or shower head, not the heater — unscrew the aerator or shower head and clean the scale. Lisbon water is hard and this happens more often than people think; see limescale and hard water in Lisbon.

If pressure is low everywhere, cold water included, read low water pressure in the shower.

4. Electric tank: breaker, switch and thermostat

For a termoacumulador, go to the fuse board and look for a tripped breaker, often labelled "termo" or "água quente". Reset it. If it trips again straight away, leave it off: the heating element or its wiring may be faulty, and repeated resets can make it worse.

Check any switch or timer next to the tank. Many flats have one, and a timer set to the wrong hours after a power cut is a classic cause of cold showers.

If the breaker is fine and the tank is still cold after a few hours, the element or thermostat may have failed. That needs a professional.

5. Warning signs: stop and call

A yellow or orange flame, black soot around the heater, a smell of gas, or headaches and drowsiness when the heater is on are signs of bad combustion and possible carbon monoxide. Switch it off, close the gas, open the windows and do not use it until it has been checked. More in esquentador and carbon monoxide.

Water dripping from inside the heater, or a tank whose safety valve pours water continuously, also needs a professional.

6. Worn parts and age

If none of the above explains it, the fault is inside the heater. In an esquentador the usual suspects are the ignition electrode, the flame sensor (thermocouple), the water valve diaphragm or a filter clogged with scale. In a tank it is the element, the thermostat or the safety thermostat.

Heaters over 10 to 15 years old often cost more to repair than they are worth. We always give you both prices — repair and replacement — when both make sense.

If you rent: who does what

Tenants are usually responsible for small consumables such as batteries and gas bottles. The appliance itself belongs to the property, so a breakdown due to wear and tear is normally for the owner to fix.

Tell your landlord in writing (a message or email is fine) with the date and what you have already checked. A plumber's short written description of the fault helps if there is any disagreement.

A quick checklist to keep on your phone

Gas: bottle full? Valve open? Hob working?

Batteries: replaced in the last year?

Flow: hot tap fully open? Shower head clean? Cold pressure normal?

Electric tank: breaker on? Switch or timer on? Waited long enough after a power cut?

Warning signs: yellow flame, soot, gas smell, headaches? If yes, stop and call.

Still nothing: photo of the heater label, and call a plumber.

Common fault codes and blinking lights

Many modern esquentadores show an error code or a blinking light when they stop. The codes differ between brands, but they usually point to ignition failure, overheating, a flue or fan problem, or a water flow sensor.

Look the code up in the manual (most are available online by model number). A code that relates to the flue or combustion is a reason to stop using the heater until it is checked, not to keep resetting it.

After a power cut or a water cut

Ventilado and estanque heaters need electricity for the fan and controls; after a power cut they may need to be switched off and on at the socket.

After a water cut, air and sediment can reach the heater. Run the taps (cold first, then hot) for a minute to purge air before expecting hot water. If sediment has blocked the inlet filter, the heater may not start until it is cleaned.

When the problem is seasonal

In winter the incoming water is colder, so the same heater delivers less hot water at the same temperature. A heater that was just enough in summer can feel weak in January.

If that is the case, turning the temperature up on the heater and slightly reducing flow at the shower often solves it. If not, the heater may be undersized for the household.

Frequently asked questions