It’s capacity is 215 litres per the illustration of the model name plate previously supplied by @esahc.
Does the unit only heat half the volume because of where the thermostat is located? Since the storage tank is designed for use with a heat pump with a circulating pump, it is different from the old resistive heater designed HWS.
The thermostat location half way up the tank or a little higher is also used by other popular and well known brands. EG Rheem.
Is the DynaHeat product design faulty, or is there a fault with the unit supplied to @esahc, or is the household making demands on the 215l greater than an average household of similar size?
It’s open for @esahc to ask Eco Alliance to respond to this discussion based on the suggested defects with the product.
Basic Design
My understanding of how some of these heat pump systems in general are designed. Generic DynaHeat and Rheem as examples.
The circulating pump ensures reheating the full volume/capacity of the storage tank to the set temperature. Once the recirculating water drawn from the bottom of the storage tank reaches the thermostat setting the system shuts down. As hot water is drawn off from the top of the tank cold water replaces it in the bottom of the tank until such time as the volume consumed allows the cold water to rise to the level of the thermostat. When this point is reached the heat pump will restart and reheat for the volume drawn off. This may not happen immediately if the heat pump is on off peak or a timer for solar. In this instance the balance of the volume of hot water remains available until it is used or until power comes back on. Approx 215l total for the DynaHeat in this example if working reliably. Each brand and model appears to use slightly different heights (volume percentage of hot water used) for the thermostat position.
Heat pump HWS systems of this type of design will appear to give approx 50% of their capacity. IE cycle once every 110l approx of consumption for the system subject to the prior complaint. Although if they are on a off peak or a timer it is still possible to draw the full storage capacity 215l, before power is required to reheat.
I am aware that others with my hotwater service appear happy, but with 3 adults in this household the hotwater service cannot provide for 3 showers within a 2 hour period (insufficient capacity?). It reheats in the early hours every day (insufficient insulation?). Just appears to me it was built to a price
I haven’t had mine running for long enough to be conclusive but I certainly don’t have any of the problems you list except for that bloody valve.
a) the thermostat is above the heat pump inlet so it measures the output of the heat pump. The purpose of this is so that the heat doesn’t turn on until at least a reasonable part of the tank has been used. To avoid excessive cycling. If the thermostat was at the bottom it would turn on as soon as any cold water entered the tank. If it was at the top it would turn off even if there was only a few cm of hot water at the top of the tank. It is at the optimum position to balance these two conflicting functions.
b)We have lived on tank water all our lives. So it supplies enough for a dozen of our showers. Even if you used pure hot water at 20 litres per shower it would supply 8 showers with no reheating. You must use a LOT more water than we do per shower. If I used that much water my rainwater tank would run out in less than half the year.
c) At the moment ours runs for under an hour per day. To supply two showers and keep the tank to 55 C
Given that it is no longer on dedicated circuit it isn’t quite as much of a saving as you might expect because although it is using a lot less electricity the rate is now 28 cents per kw hr where on off peak it was 17 cents per kw hr.
I used to notice the increase in use of electricity depending on how many showers were taken on any given day, now I cannot see any particular increase. It is a lot more efficient on hot water out for the electricity in.
Incidentally when taking the tank entirely full of cold water it reached 60C in about 4 hours.
d) part of the change is that now I can run it fully off even a small solar panel. 800W when running is not going to overload the panels so once they are functional it will cost zero to run.
e) the thermo valve does restrict the hot water and it limits the maximum temperature of the hot water but it makes the tank able to supply more hot water out at this lower temperature. It is all part of government regulation on what temperature is safe. But it is marginal for washing dishes. If the valve was removed the temperature set to is 55C by default and that is enough to wash dishes. The eco valve prevents this temperature being reached at the output.
Welcome to the community @smithyofshepparton.
It’s helpful to others when we can share our experiences.
The same here. Although we are currently under an east coast low. No shortage of supply. Our shower has a WELS 3 Star Aio Aurajet. As good as any shower we’ve ever had. 20l of HW is enough for a 4-5 minute shower with the house pump set at 220kPa.
Not everyone may follow the same shower preferences. Some may prefer the near scalding Japanese hot tub experience. I follow common advice to shower at moderate near body temperature (35-40C) to help maintain good skin health.
