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.
Heel pain is a common symptom that has many possible causes. Although heel pain sometimes is caused by a systemic (body-wide) illness, such as rheumatoid arthritis or gout, it usually is a local condition that affects only the foot. The most common local causes of heel pain include: