Heat-Timer® Corporation

Domestic Hot Water Solutions for Older Commercial Buildings

The graying of residential buildings is a very real problem for building owners, especially in older US cities like New York and Boston. In fact, in a recent study published using data from NYC’s PLUTO database, one can determine that the median age of a surviving residential building in greater NYC is over 90 years old!

As initiatives like Local Law 97 and other go-green rebate programs drive upgrades and updates to heating system infrastructure,the other frontier in the upgrade of these buildings has to do with their solutions to domestic hot water and the ever increasing difficulty of delivering consistent, and safe hot water to residents. With the dramatic increase in reported cases of deadly legionella bacteria in the water supply across the country (including recent outbreaks in NYC) the pressure is on for building owners to provide updated solutions that satisfy city regulations for safety, provide safe, consistent temperatures to folks at their sinks and showers, and do it as efficiently as possible.

Common Problems with Domestic Hot Water Systems in Older Buildings.

At the end of the day, the net problem is getting reliable hot water to residents safely, at all hours of the day. Especially so called rush hours, when demand for showers and such is high. Yet age and other factors conspire to keep older DHW systems from maintaining their operational readiness.

  1. Leaky Storage tanks. – Every tank has a shelf life of 15 – 30 years.
  2. System Sizing – Changes to apartment layout, resident count and increases in peak demand over many decades, can tax an existing system not designed for it resulting in frequent rebuilds of the light-commercial gas water heater originally spec’d. These rebuilds are expensive and wholly unnecessary in a properly sized system.
  3. Dissolved Mineral Content – Hard water supplies with high mineral content can tax piping and valves leading to expensive periodic rebuilds or replacements that take down hot water for the entire building.
  4. Temperature Creep – Older thermostatic mixers can fail in such a way as to prevent mixing during dormant periods, such as overnight. In these cases, the first hot water users in the morning can find the hot water initially arriving at the sink or shower to be almost 160 degrees Fahrenheit, a temperature that can cause burns and scalding in a matter of seconds. These mixers then have to be rebuilt causing more expense and downtime not to mention potential lawsuits.

Heat-Timer® ETS is a Key Part of the Modern Solution to DHW Upgrades

Whatever heating technology your domestic hot water solution employs, a good heating design engineer will specify a DHW system designed for reliability, efficiency, serviceability and longevity. In 2022 with outbreaks of legionella on everyone’s mind, we must also add Safety to that list.

One key part of this upgrade is an electronic mixing valve like the Heat-Timer® Electronic Tempering Valve to finally deliver perfectly regulated hot water to residents. Heat-Timer® encapsulates this system into our Electronic Tempering Station (ETS) which is a pre-plumbed, small footprint assembly saving installers hours and hours of time doing installation, and limiting overall install downtime. The internal ETV control module uses remote sensors tied to proprietary algorithms to electronically control one of the industry’s most durable 3-way stainless steel mixing valves. The Heat-Timer® ETS can deliver an adjustable domestic hot water temperature to the end user, under any condition allowing hot water to be stored at a temperature that kills bacteria, while providing perfectly safe temperatures to users at the sink.

The presence of dissolved mineral content can present a challenge to any valve design long term. One solution to the reliability requirement of a hot water system is a level of redundancy in the specification of components. In a properly designed domestic hot water system, no failure of a single component should take the system down.

A common solution to this is a dual valve ETS configuration. By specifying a second ETV or ETS Duplex, piped Isolation valves can be installed all around the mixing valve. In this way if the motorized valve fails due to scale, the alternate mixing valve can be immediately engaged, and there is virtually no downtime to end users. When you are finally able to repair the other valve, the replacement takes 30 minutes, not all day like before.


For more information on the ETV or ETS in your domestic hot water solution, call Heat-Timer® today.