In the kitchen in work we have a water heater. It's fairly new, only about a month old. It's also not very good, spending most of it's time holding water at around 80°C, not enough for a proper cup of tea.

There's a button to press to force it to reheat the water but it often has the opposite effect. If I press it when the temperatures reading in the 80's, it often drops to 70-odd degrees before slowly climbing.