Water dispenser not heating or not cooling: thermal fuse, compressor and airflow

• Switch off the MCB and unplug the appliance before checking anything.
• Make sure your hands and the floor are dry.
• Let the appliance cool down before touching anything inside it.
• Keep your hands and face away from hot steam.
• Never puncture, cut or recharge the refrigerant lines; that work is for a certified technician only.

Water from the dispenser's hot tap can be scalding. Keep children away while you test it.

A dispenser has two separate systems. The hot side uses an electric heater in a small tank. On many dispensers, the cold side uses a compressor and refrigerant, like a small refrigerator. The Modena DD 7315 manual names the refrigerant as R134a, and the Philips ADD4954 manual also lists R134a in its specifications. Because the two systems are separate, often only one of them has a problem, and the causes differ too.

Each side has its own switch on the back. The Modena manual says to use these switches to turn the heater and cooler on or off. The Philips manual describes a black heater switch with high, low and off positions, plus a green cooling switch. The Philips ADD4954 specification lists a heating power of 170W/350W at 220V-240V. A low-power heater like this takes time to reheat the water after heavy use.

So the first step is always the same: look at the switches on the back, then give it time. Only after that is it worth suspecting the parts inside the cabinet.

1. Switch and plug. Make sure the plug is in and the heater switch on the back is on. The Modena manual names a plug that is not pushed in properly, or a switch in the off position, as the first cause of a dispenser that does not work.
2. Give it time. The Philips manual says hot water takes about 30 minutes in position I and about 15 minutes in position II. The Modena manual explains that the water may not be hot if a lot of hot water was used in a short time; wait a while for it to heat up again.
3. The hot tank must have water in it. Both manuals forbid switching the heater on when the hot water tank is empty. Make sure water flows from the hot tap before you plug in and switch the heater on. The Modena manual also says to switch off the red heater switch before replacing an empty bottle.
4. Trapped air after a bottle change. Sanken explains that trapped air can keep water from reaching the heater. Switch the dispenser off and unplug it, then hold the hot tap open until the water flows smoothly without gurgling, and only then switch the heater back on.
5. The heating light is completely off. Sanken explains that if the indicator light is completely off, the thermal fuse has probably cut the power to protect the heater, because the tank was empty while the heater was on. Some Sanken models have a thermostat reset button on the back. If your model has no such button on the outside, do not open the cabinet; contact the service center.

A dispenser's cooling system gives off heat through a condenser at the back, just like a refrigerator. If that heat cannot escape, the water does not get cold.

1. Cooling switch. Make sure the cooling switch on the back is on. The Philips manual says cold water takes about an hour after the green cooling switch is turned on.
2. Gap to the wall. The Modena manual says the dispenser should stand at least 20 cm away from walls, appliances and furniture on all four sides. The Philips manual asks for a 15 cm gap between the unit and the wall, with the vents on the back kept clear.
3. Location. Keep it out of direct sunlight and away from heat sources. Philips says the unit should stand in a dry, ventilated place, not outdoors or anywhere rain can reach it.
4. After moving it. The Modena manual says to let the unit stand upright for 1 hour before first use so the refrigerant settles, and forbids turning it upside down or tilting it more than 45 degrees. Philips gives the same tilt limit to avoid damaging the compressor. If the dispenser was laid on its side on the way home, let it stand before switching on the cooling.
5. Heavy use. As with hot water, if a lot of cold water is used in a short time, it needs time to cool down again.

The Modena manual describes the sound of the compressor switching on and off, and of the pump when water is drawn, as normal.

On a dispenser with the bottle at the bottom, water is pumped up to the hot and cold tanks. A problem along this path is easy to mistake for a failed heater or cooler. The Modena DD 7315 manual says no water comes out of the spout if the unit is not plugged in, the bottle is empty, or something is blocking the pipe. When the water runs out, the hot and cold indicators on that model blink at the same time.

Check that the suction tube reaches the bottom of the bottle and that the bottle cap is fitted tightly, as the installation steps describe. Switch the heater off before you replace an empty bottle. The same manual says the sound of the pump running while water is drawn from the spout is normal.

The Philips manual says to clean the water tank and pipes before first use and after a long time out of use. The system should also be washed and disinfected every 3-6 months with a suitable cleaner, with the heater switch off while you drain it. The Modena manual explains how to drain it: unplug it and run water from the taps until nothing comes out. Then remove the drain cap on the back over a large bucket, and put the cap back when you are done.

• Tighten the drain cap before use; Philips warns that a loose cap leaks water onto the floor.
• Clean the dust off the black condenser at the back without bending its tubes.
• Do not pour water over the outside of the unit; clean it with a soft cloth.
• Leave the thermostat alone; the Modena manual says it is factory-set and must not be adjusted.

Well water, or refill water with a high lime content, leaves scale in the hot tank. Draining it regularly helps the heater keep working normally for longer.

Contact the authorized service center for your dispenser's brand if:

• the heating light is completely off with the switch on and water in the tank (the thermal protection or thermal fuse inside the cabinet needs checking);
• the heating light is on but the water stays cold after the waiting time in the manual;
• the cooling does not work even with the switch on and the vents clear. The Philips manual names a faulty cooling switch or a loose electrical connection as causes for service personnel to handle;
• there is a leak from the tank, a pipe or a tap (Philips says to contact service personnel);
• you smell burning, the power cord is damaged, or you suspect a refrigerant leak;
• the dispenser often trips the house MCB.

Bypassing the thermal fuse, opening the thermostat, replacing the heating element and repairing the compressor or cooling circuit are jobs for a technician. The Philips manual stresses that the cooling circuit must not be damaged, and that you should not replace a damaged power cord yourself.