As a standard immersion heater is 3KW, so it would take 2 hours to heat 100 Litres of water. After an hour and a half, it will only have reached about 53 degrees.....
Podiatrists cite Plantar Fasciitis as being the most common cause of heel pain. Typical symptoms of this condition include sensations of pain, burning or heat in one or both heels.
The most common causes of heel pain are plantar fasciitis (bottom of the heel) and Achilles tendinitis (back of the heel). Causes of heel pain also include: 1  Achilles tendinitis. 2  Achilles tendon rupture.  Bone tumor.