Heating and hot water appliance manufacturer Rinnai is encouraging its customers to ‘trade up’ rather than going ‘like for like’ when it comes to considering a replacement, high performance, high efficiency hot water solution.
‘Like for Like’ is the assumed replacement when a stored water system or unit comes to the end of its working life. But is it always the best option? Changing the ‘same old’ for the ‘same new’ does not mean a better, more efficient, more responsive, less costly outcome. For starters, most plant rooms are limited in space, which would require old equipment being removed before new appliances can be installed.
Easy access and continuous, limitless flows of hot water at peak demand are critical components of building services for all applications on all sites.
Peter Seddon of Rinnai gives an example: “If the appliance being replaced was non-condensing and the new appliance is condensing, the flue would most likely require changing as well as the provision to discharge condensate. Plant rooms are very rarely designed to remove equipment. This requirement to remove equipment before new is installed would have a major impact – and it takes so much time.
“The hot water system would have to be completely shut down to allow such major works to take place and sites, especially healthcare ones, cannot allow this to happen.”
The size and weight of these older appliances can make life exceedingly difficult for installers. They are usually manufactured with enamel lined (glass lined) mild steel which can make them extremely heavy but also very fragile. Multiple personnel are required to manoeuvre these, and specialist lifting equipment and even cranes may also be required, adding a lot of time and cost to the overall installation. Not only that, but if specialist lift equipment and cranes are required, suitably trained personnel, as well as permits, will be required.
Says Pete Seddon: “So, what can continuous flow solutions offer that can make this entire process a lot easier? Well, we will start with their size and weight. This type of technology is 30kg. That is a one-man lift. Two sizes are available – 47kW and 58kW. This would equate to a large volume of hot water for such a physically small appliance (774 and 954 litres per hour at a 50-degree rise).
“The other benefit is the ability to cascade these appliances so that when more hot water is required you would simply add more continuous flow water heater units. This would mean that just a single installer could create a system that would produce vast amounts of temperature-accurate hot water whilst also creating built-in redundancy – this means that if one unit needs to be shut down, the complete site still has ready access to 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 installers 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. Simple as that.”
With a continuous flow system there are also externally sited units where there is just no space in a plant room. These external hot water heaters are fully weather protected and hold IPX5D rating. Installations also come with frost protection down to -20°C and will keep the appliance protected so long as the mains power supply is left switched on.
When measured in economic performance, continuous flow water heaters on a Peak Period of 3 hours per day at 960 I/h cost around half that of a combustion unit. A typical water storage-based installation will cost £5,662.13 per year, where by comparison a Rinnai continuous flow water system will cost £2,736.02.
