How many hours maximum vodonagrevatel can be included?

Electric water heaters are designed for long, continuous operation. However, it is not always so used. The water heater in the shower we turn on in night mode, in the morning you can wash, already disconnecting from the network. So it saves energy. The heater in the sink, you may need to use intensively and then working around the clock, but in the case when the demand for hot water is not high, then turn on the timer for heating at night. Its volume is enough to wash the dishes a few times, hands. In the sink once the water heater refused, cover heater, replace a new one did not work and bought a new one. New works for a long time, even forgot when purchased. In General this technique is fairly reliable, in my opinion.
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