Immersion Heater Not Working
The immersion switch is on but the cylinder stays cold, or it trips the consumer unit..
The immersion switch is on but the cylinder stays cold, or it trips the consumer unit.
What is actually going on
The immersion switch is on but the cylinder stays cold, or it trips the consumer unit.
The realistic causes, in order
A tripped thermal cut-out on the immersion stat after an overheat event A burnt-out element, often scaled solid in hard-water areas Damaged flex or a failed switch at the wall, which is an electrical fault rather than a plumbing one
What we test on site
Continuity and insulation resistance across the element Whether the cut-out has operated and why, rather than simply resetting it Cylinder thermostat calibration and mounting
Safe checks to make with an immersion heater that won't heat
- Check whether the circuit breaker for the immersion has tripped
- Confirm the timer or switch is genuinely calling
- Immersion work is electrical. A scaled element that trips a breaker should be replaced, not repeatedly reset.
Who does the work
- Gas Safe registered engineers — registration 554328
- Worcester Bosch accredited installer
- John The Plumb Ltd, company registration 10026483
Get an immersion heater that won't heat diagnosed properly
Element and stat replacement together is the sensible approach, since both age at the same rate.
Questions we get asked
Does an immersion heater that won't heat mean the cylinder needs replacing?
A tripped thermal cut-out on the immersion stat after an overheat event
What normally puts an immersion heater that won't heat right?
Element and stat replacement together is the sensible approach, since both age at the same rate.
Is it safe to keep using the system with an immersion heater that won't heat?
Immersion work is electrical. A scaled element that trips a breaker should be replaced, not repeatedly reset.