Heat Merchants Willis Immersion Heater

The Willis type immersion is fitted in parallel to the main domestic hot water cylinder and heats the water from the top down. So, for a shower (typical requirement – 35 litres @ 40°C), the Economiser will heat only the top 35 litres of the cylinder in about 10 minutes, and the unit should then be switched off.For maximum efficiency we recommend that the Economiser be fitted in conjunction with a timer. This will ensure that the heater is switched off after the required time. You can then set it and forget it.