Heat Timer Corporation

What is a Domestic Hot Water System? A Domestic Hot Water (DHW) system provides potable hot water to our sinks, showers, and tubs and other places where hot water may be ingested by, or come in direct contact with humans. This is as opposed to non-potable water which is not suitable for drinking and other domestic purposes but may be used for hydronic heating, industrial cleaning and other applications. Most plumbing codes specify that all piping, components, and heat-transfer devices in contact with the potable water shall be intended for use in potable water systems. Typical commercial DHW systems consist of one or more boilers that provide a reserve of hot water for use. Since demand for hot water is not uniform across the day, DHW control systems are sized to try to balance the costs of heating large tanks of hot water, while still being able to meet the anticipated demand during a peak period (usually when people are getting ready for work in the morning) Key Parts o...

The relentless march of new technology in the area of boiler design and domestic hot water systems, have given us many new and improved components and strategies for providing safe, and more energy efficient heat and hot water . But the news is not all good: the fact is that since 2000, cases of Legionella as reported by the CDC have actually increased across the USA. While many possible reasons exist for this puzzling fact, the fact is that even the CDC doesn’t fully understand why. Certainly, awareness of the disease has increased. Cases that were previously unknown are now properly diagnosed and easily reported on the internet. The increase in Legionella cases also does not differentiate incidents which are related to domestic hot water systems vs. those involving other systems such as cooling towers and air conditioning systems. And finally, increased aeration in the water due to low flow fixtures along with the aging population and infrastructure could also be contributing fa...