Because of regulations put in place after the outbreak of legionnaire’s disease in the 90’s, installation of Domestic Hot Water (DHW) systems were changed for the sake of public safety. All DHW systems, whether storage based or tankless, must now meet the conflicting requirements of holding DHW at a minimum of 140°F (60°C) to comply with such standards as OSHA Technical Manual Section 3 Chapter 7, to combat Legionella growth, while delivering hot water at a temperature that prevents scalding injuries in sinks and other fixtures.
For decades, commercial plumbing installers have embraced a 3 way mixing valve or “tempering valve” as the perfect solution to the dilemma. Early tempering valves were controlled manually with fixed setpoints, but in 2020 we have evolved to using motorized valves under the direction of a standalone electronic control station that adds flexibility, reduces energy use, provides alerts and alarms, and generally improves the safety of any domestic hot water system. One of the most popular motorized tempering valve solutions continues to be the Heat-Timer ETV Platinum PLUS Electronic Tempering Valve (ETV). The ETV allows building owners to keep their water heaters and storage tanks above 140°F (60°C) while distributing hot water to users within a safe range. The Heat-Timer ETV control also has the ability to control a safety valve which shuts off the supply of hot water whenever the mixed outlet water exceeds an adjustable high temperature limit and provides a remote alarm to building managers.
One thing to consider even with a tempering valve system solution as advanced as the ETV, is the amount of time required for a contractor/plumber to plan, stage and install the entire system.
Consider that the basic system requires a sturdy frame to support and hold all of the components; the electronic tempering valve, safety valve, multiple pipes, unions, check valves and shut off valves, all need to be mounted to the frame while routing all piping connections in a neat and logical way to the Cold & Hot water supplies, water heater, recirculating loop and Mixed hot water output while allowing easy maintenance of the system. Low voltage wiring connections need to be made between the control module, ETV and temperature probes and a 120v, power wiring connection is needed for the ETV control module. The ability to mount the ETV control Module up to 500 feet from the valve offers increased flexibility for installation of system components.
Once completed all piping needs to be leak tested and all wiring needs to be verified for correct installation. Now, the system is ready for operation.
From years of experience, we can tell you that commercial plumbing contractors approach the challenge of installing a complete DHW system in one of three primary ways:
Regardless of the skill and experience of the installation team, none of these approaches will eliminate the on-site time and expense needed to fit, assemble and test all of the components required.
With Heat-Timer®, there is another, and better alternative – installing a fully integrated, pre-plumbed, pre-wired Electronic Tempering Station.
The Heat-Timer ETS Is the Pre-Plumbed Tempering Valve Solution Contractors and Engineers Have Asked For.
The Electronic Tempering Station (ETS) is a factory assembled and fully tested DHW system. Only five piping connections and a single 120V electrical connection are required to complete the installation. The entire compact system is mounted in a sturdy steel frame, ready to be bolted to a pad.
Once the mixed hot water requirements (gpm) of the building are known, designing a correctly sized DHW system is as easy as selecting the correct valve size. Once you’ve chosen a location, your only field work is to connect wiring for the 120v power supply and five piping connections. (Recirculation return, water heater/storage tank supply, Hot & Cold water supply and Mixed water outlet). The station also comes in both single and duplex (dual valve) configurations. The duplex models are designed for hot water distribution systems needing large quantities of safe tempered hot water, saving your customer money and you even more work.
Using the ETS, is Fast, Efficient, and Yes, Economical
The ETS is designed by an experienced engineering team, which ensures that the systems are fully code compliant. Heat-Timer® also provides detailed assembly drawings to allow contractors to accurately rough in the necessary connections. The money building managers and contractors save in installation time, raw materials, and quality generally pays for the cost of the ETS outright.
With the Heat-Timer® ETS, our contractors get the advantage of rapid, trouble-free installation and code compliance, while the building manager gets faster occupancy and an easy to service system with the advanced control and monitoring features of the Platinum Plus ETV control module.
The Heat-Timer® ETS is a win-win for everybody!
Original content posted on https://www.heat-timer.com/water-safety-for-all-time/
We all know the importance of rotating our tires. On most vehicles, tire wear is uneven front to back, so manufacturers recommend tire rotation at every oil change. Tire rotation enables all four tires to wear evenly, so they can all be replaced at once when they are worn.
Unfortunately, even with proper maintenance, a tire will still fail occasionally due to a stray nail or a winter pothole. That is why most cars still carry a spare tire that can be swapped in for the flat tire, preventing you from being stranded far from home late at night.
It turns out that a similar situation exists for building managers looking to the health and efficiency of their hydronic heating systems. Much like our tire rotation analology, failure to rotate the hydronic load across the system can lead to early pump failure and unnecessary replacement expenses.
What is a Pump Sequence Control?
A pump lead-lag (PLL) controller (also called a pump sequence controller) can balance the run time of multiple boiler pumps to minimize the number of scheduled and unscheduled service calls. It can also automatically manage a backup or standby pump, which like a spare tire, will be ready to use in case of a pump failure. Unlike a spare tire, which requires a roadside repair to install, the PLL will switch over to the backup pump automatically, with no interruption in heating system availability.
A simple system managed by a PLL consists of two or three pumps. Each pump is sufficient to meet the heating system demand. The PLL controller will balance the run time between the two pumps, as much as doubling the preventive maintenance interval of the pumps. An example of a simple 3 pump system is shown below:
In this system, the Heat-Timer PLL Control is shown with a 3 pump single boiler configuration. This system is often referred to as a 3 pump, 1 call, 1 flow piping. Named because there is only one place where hot water is called to the heating system and only 1 flow from the boiler to the pumps. In the above configuration the Heat-Timer PLL controls the pumps, the flow switch, and monitors the input of “proof of flow” sensors. With these capabilities and more, many configurations of boilers, pumps and number of calls and flows are possible. For instance, in a two boiler system, the Heat-Timer® PLL can manage three pumps; two primary pumps, one for each boiler, and a back-up pump that can automatically connect to either boiler via PLL controlled solenoid valves. The PLL monitors the flow to each boiler. If the flow to one boiler is interrupted, then the PLL will open the solenoid valve between the backup pump and the boiler with the failed pump. The backup pump will then provide uninterrupted flow to the boiler until the primary pump can be replaced.
Our Tire Rotation Analogy Extended
Honestly, who would remember to rotate their tires at the scheduled interval if the dealer didn’t nag you?
Fortunately for building managers, a PLL control operates completely independently. It would be as though your tires rotated themselves every 10,000 miles. Heat-Timer’s PLL control for instance offers two distinct modes of rotation, either time based rotation or alternating demand rotation which activates a different pump each time a call for hot water is initiated.
Sometimes no matter what you do, you get a flat tire. Likewise if one of your pumps should fail, you need to know immediately. The Heat-Timer® PLL control continuously monitors pump flow rate to the boiler or boilers. If the on-call or primary pump fails the PLL can sense the interruption in flow in less than a minute and immediately failover to the remaining pump or the backup pump. An alarm is set locally on the panel and can be sent to alert building management of the pump failure. Because of the automatic failover, there is no interruption to building heat and to the comfort of the occupants and no weekend or holiday emergency call.
Having a spare tire is useless if it is flat when you need it. When was the last time you checked the pressure in your spare tire? Having a back-up pump that won’t start when needed is equally useless.
A building manager does not need to worry about this because the Heat-Timer® PLL can prevent having a “flat spare”. Our controllers have an “exercise” feature that will periodically run standby pumps for a short time to break up rust and sediment and lubricate pump seals. Periodic exercising of the back-up pump will ensure that it is ready to run when called on.
Heat-Timer® PLL Controller is A Robust Solution to Multiple Pump Management
For the building HVAC manager, adding a second or third feedwater pump controlled by a Heat-Timer® lead-lag controller is an inexpensive way to increase hydronic heating system reliability, while reducing expensive emergency service calls and preventive maintenance intervals. What used to be a late night emergency becomes a minor problem that can be dealt with at a convenient time.
Original content posted on: https://www.heat-timer.com/pll-controller-is-a-robust-solution-to-multiple-pump-management/
Heat-Timer® corporate office and manufacturing facility is conveniently located in Fairfield, NJ. Here, Heat-Timer® manufactures its electronic controls, sensors, valves and actuator products using specialized computer controlled equipment and automated testing systems.