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Don’t Replace “Like For Like” When It Comes To Hot Water Systems, Says Rinnai

Don’t Replace “Like For Like” When It Comes To Hot Water Systems, Says Rinnai

June 10th, 2020

Hot water for handwashing and hygiene is a critical component in combating the COVID-19 virus, especially on healthcare sites.

For many years, gas-fired storage or cylinder tank water heaters were the preferred mode of hot water delivery. However, new technology in the form of continuous flow can give limitless amounts of hot water.

So when a stored water unit comes to the end of its working life, or has failed, it is sometimes assumed that replacing “like for like” is the easiest solution.

However, according to Rinnai, new technologies and practices are combating the current public health challenge. The technology in hot water delivery is continuous flow hot water heating, with temperature-accurate and controlled delivery.

“If we look at the ‘like for like’ method, out with the old one and in with a new gas-fired stored water heater, there is actually a major amount of work involved in this."

–Pete Seddon

Product Development Engineer, Rinnai

“Changing old for new does not mean it is better”

During the lockdown, Rinnai has continued to offer full support services to essential works such as NHS facilities, care homes, schools and supermarkets.

Part of this key service is providing on-demand hot water using continuous flow technology, and Rinnai is warning their clients to think twice before assuming that a traditional gas-fire stored water heater is their best option.

Rinnai advises that any site needing a new hot water heating and delivery method should start with the design and sizing of the system. Before it is updated, it is important to check the current system can produce the hot water required that day.

Pete Seddon from Rinnai, a UK supplier of continuous flow units explains further, “If we look at the ‘like for like’ method, out with the old one and in with a new gas-fired stored water heater, there is actually a major amount of work involved in this.

“Changing old for new does not mean it is better. Most plant rooms are limited in space which would require the old equipment to be completely removed before the new one can be installed.

“Not only that, but if the appliance being replaced was non-condensing and the new appliance was condensing, then the flue would most likely require changing. This is in addition to the provision to discharge condensate.”

Seddon also explains that plant rooms are rarely designed to allow the space for equipment to be dismantled before its removed. “It takes so much time. And time is in short supply now,” he adds.

“The hot water system would have to be completely shut down to allow such major works to take place and a healthcare site cannot simply allow this to happen.”

Guaranteed to supply temperature accurate hot water

Due to the size and weight of these older appliances, installation can also be problematic. They are usually manufactured from enamel-lined (glass-lined) mild steel, which is not only heavy but very fragile, potentially requiring specialist lift equipment.

Seddon explains how continuous flow solutions can make this whole process a lot easier:

“This type of technology is normally a similar size to a modern-day combi boiler, weighing at most 30kg, which is a one-person lift. This type of box is available in two sizes, equating to either 774 or 954 litres per hour at a 50-degree rise.”

Provided there is a constant supply of gas and water, these units are guaranteed to supply temperature accurate hot water in unlimited quantities in all types of healthcare sites or temporary accommodation.

Cascade sequencing control

Seddon adds that these systems are also able to be cascaded, so when more hot water is required, you simply add more continuous flow water heaters. This means that just a single installer could create a system that would produce vast amounts of temperature accurate hot water.

“Also possible is a ‘plug and play’ cascade sequencing control system that will automatically control how many appliances are running at any one time, all the installer would have to do is plug it in and select the primary water heater. Continuous flow can easily cope with any size of healthcare site. It’s as simple as that.”

One of the big benefits that Rinnai has seen with the utilisation of the cascade frames, is the fact that a lot of the installation works can be carried out while the existing equipment is still in place.

This is dependent on floor space within the plant rooms, but Rinnai says that this tends not to be an issue. The cascade frames are bolted to the floor and the water heaters mounted on to the frames. This will then allows some of the pipework to be started, as well as some of the flueing installation. 

Picture: A photograph of a typical plant room with Rinnai hot water systems

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