ᐅ Hot Water Generation Heat Pump

Hello, since July 13th, my heat pump has been in operation. Domestic hot water temperature is set to 46°C (115°F), setback temperature to 36°C (97°F), and hysteresis to 5K.

I am currently testing the hot water production. The day before yesterday, around 5 p.m., I heated the 200-liter (53-gallon) storage tank to 50°C (122°F). The next morning, the temperature had dropped to only 41.5°C (107°F), although only one person had showered so far. A 9-degree drop by 10 a.m. seems too much in my opinion. The circulation pump ran for 3 hours in the evening and 2 hours in the morning. What are your experiences?

Yesterday, I noticed the following in the WEM portal:
2nd Heating Circuit:
Bivalence temperature -5°C (23°F)
Bivalence temperature for domestic hot water 40°C (104°F). Variable output on timer, probably for the domestic hot water circulation pump.

I have never heard of a bivalence point for domestic hot water. What does this mean?
Best regards

With 200 liters (53 gallons), an initial temperature of 50 degrees Celsius (122°F), plus a decent shower (after 10 minutes, depending on the rain showerhead, you might run through 250 liters (66 gallons)), five hours of circulation, and overnight, it is completely normal to have 9 degrees Celsius (16°F) less in the tank the next morning. You will only change this if you use less hot water (turn off the shower in between or reduce shower time, or use a different showerhead) or lower the (unnecessary) circulation.

KarstenausNRW schrieb:

With 200 liters (53 gallons), a starting temperature of 50°C (122°F), plus a nice shower (after 10 minutes, depending on the rain shower head, you might have used around 250 liters (66 gallons)) and five hours of circulation plus overnight, it’s completely normal if the tank temperature is about 9°C (16°F) lower the next morning. You’ll only change that if you use less hot water (turn off the shower intermittently or reduce shower time, or use a different shower head) or reduce the (unnecessary) circulation.

Thanks for the information. So it’s enough to run the circulation pump for about 30 minutes in the morning and evening. Do you know what the bivalence temperature for hot water at 40°C (104°F) means when using the heating element?

Turn off the circulation pump completely!
Heat the hot water once a day, preferably around midday. I have a 300-liter (79-gallon) tank and heat the water to 45°C (113°F) right after the utility lockout, so that no heating cycle is interrupted.
Circulation pump completely off.
This is more than enough for 3 people, including baths!

Alessandro schrieb:

Turn off the circulation pump completely!

To then turn the dead leg into a breeding ground for germs?
Not a good idea...

Then just turn it on once for 5 minutes. But definitely not for 5 hours 🙄