This post is a description of the installation of an Ariston Velis Evo ‘electric storage water heater’. The manufacturer calls it ‘revolutionary’, and they may be right.
Physically it is only 27 cm deep, and it consists of a ‘twin tank’ technology, which provides 16% more hot water, is claimed to be shower-ready in 30 minutes, and to achieve savings of up to 25%. It boasts a best-of-class B rating.
Our first hot water heater
In the mid-70s my wife Monique bought a small ski apartment. These apartments were normally used during winter weekends and for skiing holidays. The central heating was collective and by forced warm air, and each apartment had its own hot water heater installed in the bathroom. Each apartment, no matter how small, also had a fireplace.
Certainly until 1990s the focus was almost exclusively on skiing in the winter, and summer holidays in the mountains were not popular except for those passionate about trekking and climbing.
There were two basic problems with the model seen above. This first was that 50 litres was fine for a good shower, but then the water would take around 90 minutes to heat up again for a second shower. The second problem was that the apartments electric meter was limited to 3 kW (and many people still today have the same 3kW meter). This meant that if we heated water we could not use the oven or an electric fan heater, etc.
I still remember those early days (late 70s) when every weekend, winter or summer, we would drive up to the apartment on Friday evening, and drive back down Sunday night. It was in many ways one of the happiest moments of our life together. In those days Italians used this type of apartment almost exclusively for winter ski holidays. In summer almost nobody would visit the valley, so each weekend we could just sit back and simply enjoy being together. In those early days Italian schools were open on Saturday morning, and most people worked Saturdays, leaving only Sunday free. In winter we would ski all day Saturday and on Sunday we would arrive after the morning rush up the mountain, ski until mid-afternoon, and come down before the rush in the early evening. At that time there was no motorway through the valley, so we would wait until late Sunday and then hit the road for a 3-hour drive back home near Varese.
Our second hot water heater
In 2009 we renovated our skiing apartment. The renovation included the complete kitchen area and the bathroom, including the hot water heater. The renovation was complete, e.g. electrics, plumbing, tiles, etc.
We also upgraded our electricity meter to the maximum domestic level of 6 kW.
As seen above, we also increased the hot water storage heater to 80 litres. However, just having a larger quantity of hot was not sufficient. Immediately the first person starts to take a shower, the hot water removed is replaced with cold water from the mains (mountain water is really very cold). Two showers were possible, if they were taken one immediately after the other. Otherwise, it would take between 1 and 2 hours to reheat the 80 litres, depending upon how much hot water was used in the first shower.
By 2009 our use of the apartment was exclusively in the summer months. So this delay between successive showers did not really pose a major problem. However, it was irritating.
Our new hot water heater
My initial idea was to look to replace the 80 litre tank with an instantaneous, or tankless, water heater. The topic is a minefield of options, but the key was that they were not used in the mountain valley where our apartment is located.
The principle objection was that those that worked properly operated at 9.5 kW or above, and required a 32 amp circuit breaker. That type of electric meter was expensive, and the mains cabling would have to be rewired.
Our attention turned to a…
Ariston VLS EVO water heater
The first thing is that it is also 80 litres, but the physical shape is far more functional and elegant than just a simple cylindrical tank.
Perhaps the most important feature is how it uses two tanks to provide two decent showers (40 litres), one after the other. My understanding is that it first heats up one tank, and then the other. As hot water from the first tank is drawn for the first shower, that hot water is replaced by hot water from the second tank. This means that in principle a second shower can be taken immediately, or any time later.
On the front screen it’s possible to see and program the temperature of the water, between 40°C and 80°C. And more importantly, there is a sign that indicates if a hot shower is possible, i.e. indicating if a second shower is possible after a first shower has been taken (meaning 40 litres at 40°C is still available).
On the front screen there is an ON/OFF, and there is also a ECO EVO function that ‘learns’ user consumption levels, and tried to map energy consumption to the users consumption pattern.
Additional features include:-
- The display shows the temperature of the water in the tanks, and if it is heating or not
- If the boiler is switched off, the last temperature set remains saved
- There is an ‘anti-Legionella’ function that disinfects the tanks by heating them to 60°C for one hour.
Installation
As is fairly obvious from the above photos, installation was slightly more complicated for the new Arsiton water heater.
The first two water heaters were just cylindrical tanks hung on the wall, and connected to cold water in, hot water out, and a main socket.
As was the case for the previous boiler, it was important to ensure that the wall attachments were safe. The manufacturer recommended that partition walls made of brick or perforated brick (as was the case for us) be checked for a static load of 3-times the weight of the boiler (i.e. so about 300 kg).
The installer decided to cut into the support wall a hole and fill it with fast-drying cement (as seen below). He was then able to drill and placed the support brackets.
He was particularly attentive, because he had once seen a boiler break away from its support wall.
Once hung, the next step was to pipe in cold water and connect up the hot water outlet.
In the installation of the first two boilers, they were simply connected up using flexible connector hoses. As we will see below this new installation included a number of supplementary elements.
Above we can see that the plumber reduced the ½” input and output and used a type of PVC piping, hopefully a type that resists both temperatures up to 90°C and freezing temperatures. I’m not sure but I guess it is PEX (cross-linked polyethylene) which is used today for many re-fittings, etc. I could not see any marking on the piping, so I’m not sure what type of PVC piping was used.
I’m also not sure why it was crimped, but it is said to be very solid for use with a push-to-pull compression fitting (the red bit), such as a Sharkbite-type fitting.
The water in mountain regions is hard, and the boiler manufacturer recommended the installation of a polyphosphate dispenser (seen above).
The final part of the installation, was a expansion vessel on the hot water outlet (as seen above).
Conclusion
The most important conclusion is that it works. My wife and I were able to take decent showers one after the other, without waiting for the water to heat up again.
