Hot water tank: the water heater operates in forced-circulation mode only
That’s not the way to cut your electricity bill! If your water heater is only heating up when forced to, you need to act quickly. Use this troubleshooting guide to identify the faulty part before attempting to repair it yourself or calling in a professional.
THE POSSIBLE CAUSES FOR THIS ISSUE:
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Malfunction of the day/night switch
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Faulty or malfunctioning thermostat
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Heating element is scaled up or out of order
WARNING
Before carrying out any work on your appliance, make sure you disconnect it from the mains.
Risk of electric shock.
Malfunction of the day/night switch
This is the first thing to check when a hot water tank only heats up in forced-circulation mode. To be absolutely sure, follow these instructions, taking care to observe all safety precautions :
- Switch off the power supply at your electricity meter
- Locate the day/night switch, which is usually found at the end of a row of circuit breakers
- Check whether the contactor is mechanically jammed by trying to change its position
- Once power has been restored, check terminals C1 and C2 on the contactor
If it is working properly, the timer switch should switch automatically to off-peak hours. If not, you will probably need to replace the peak/off-peak timer switch. We recommend that you call in a qualified electrician to do this.
The day/night switch is a special module fitted to the fuse box, usually at the end of a row. It allows you to switch on your water heater at night during off-peak hours. Provided, of course, that you have signed up for an off-peak tariff with your electricity supplier!
Faulty or malfunctioning thermostat
The thermostat regulates the water temperature inside the tank. If it stops working properly, it can disrupt the operation of the water heater and force it to run continuously in forced mode. To access the thermostat, remove the cover located underneath the water heater. Check that it is working properly using a multimeter set to ohmmeter mode. Disconnect the thermostat’s connectors and place the multimeter probes on the contacts, which are usually marked on the thermostat (most water heaters have a wiring diagram to guide you). If there is no continuity, you will need to replace it.
Buy a thermostat for an electric water heater
Heating element is scaled up or out of order
Is your thermostat working properly? The water heater may be limescale-clogged, particularly its heating element. This could explain the problem you’re experiencing. In this case, you’ll need to drain and dismantle your hot water tank to descale it. Depending on the condition of the heating element, you may be able to keep it after descaling or replace the faulty heating element. This is no easy task! If you have never carried out this procedure before, we advise you to call in a qualified heating engineer.