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
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
Are we talking about the circulation pump that runs at 7 watts on my Viessmann heat pump? 7 watts! Yours won’t consume more than that either.
It prevents the formation of Legionella bacteria and ensures that hot water is always immediately available at the tap (wherever that may be), helping to save water.
I run it for 3 hours in the morning and 7 hours in the afternoon until evening. That’s 10 hours total. At 39 cents/kWh, that’s €0.027 per day, which is just under €10 per year.
Keep it running...
It prevents the formation of Legionella bacteria and ensures that hot water is always immediately available at the tap (wherever that may be), helping to save water.
I run it for 3 hours in the morning and 7 hours in the afternoon until evening. That’s 10 hours total. At 39 cents/kWh, that’s €0.027 per day, which is just under €10 per year.
Keep it running...
DeepRed schrieb:
Are we talking about the circulation pump, which runs at 7 watts on my Viessmann heat pump? 7 watts! Yours won’t use more than that either.
Considering it prevents the formation of Legionella and ensures hot water is immediately available from the tap (wherever), it helps save water.
I run it for 3 hours in the morning and 7 hours in the afternoon until evening. That's 10 hours total. At $0.39/kWh --> €0.027/day (0.03 USD/day). That’s just under €10/year (about 11 USD/year).
Keep it running... The issue isn’t the power consumption of the circulation pump, but rather the heat losses. Over the course of a year, these add up significantly.
A
Alessandro1 Aug 2023 08:28Another question: how often does your heat pump heat the domestic hot water each day?
Mine does it exactly once, because I have limited it by time.
At €0.39 per kWh and about 1 kWh per hot water cycle, I spend around €142 per year on hot water.
If the heat pump runs continuously like in your case, it certainly heats the hot water 2 or even 3 times daily (assuming the hot water production is not time-limited).
Also, the heating cycles are constantly interrupted, which is not efficient.
I’d rather wait 5 seconds to get warm water from the tap...
Mine does it exactly once, because I have limited it by time.
At €0.39 per kWh and about 1 kWh per hot water cycle, I spend around €142 per year on hot water.
If the heat pump runs continuously like in your case, it certainly heats the hot water 2 or even 3 times daily (assuming the hot water production is not time-limited).
Also, the heating cycles are constantly interrupted, which is not efficient.
I’d rather wait 5 seconds to get warm water from the tap...
I’m not trying to discourage anyone, don’t get me wrong. But please take a legionella test once a year. I work professionally with germs and water circuits. Unfortunately, I have a different perspective on this than just the financial aspect.
But as I said, I’m not telling you what to do…
But as I said, I’m not telling you what to do…
R
RotorMotor1 Aug 2023 09:59Alessandro schrieb:
I’d rather wait 5 seconds to get warm water from the tap...5 seconds? You must have very short pipes...But such a decision is made before construction, not afterwards.
Once a circulation system is installed, it must be used for hygiene reasons.
And not just once a day for a few minutes.
Because flushing only lukewarm water encourages bacterial growth.
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