Hello everyone,
Last year, my wife and I bought a house. It’s not a new build but an older detached house that has been modernized several times over the years.
We have a combination boiler that runs on wood and pellets. There is also a solar thermal system on the roof, but it was only connected this year. Apparently, there were problems with the system and the heating technician was unavailable for a long time.
The system has been working very well all summer so far. I haven’t had to use any additional heating. In the past, there were a few days with very gloomy and rainy weather, so I had to add heat after about three days.
During this time, I noticed that my heating energy was being transferred to the solar collector. Of course, I discussed my suspicion with the installer, but he said that if the pump is off, no circulation is possible.
Over the weekend, my neighbor and I inspected the piping system and discovered a shut-off valve. Yesterday, I ran an experiment using this valve, which went as follows:
Yesterday at 9:30 PM, without any sunlight, the temperature on the collector’s upper sensor was 73°C (163°F). I closed the shut-off valve installed on the collector feed line. This morning at 6:00 AM, I checked again, and the upper sensor showed 16°C (61°F). I reopened the shut-off valve and went for breakfast.
After 30 minutes, before leaving for work, I checked again and, without any sunlight, the upper sensor suddenly showed 66°C (151°F), even though the pump was still off.
The pump normally only starts when there is a temperature difference of 5°C (9°F) between the lower and upper sensors.
Where do 50°C (90°F) come from in 30 minutes if not from the sun? It can only be coming from the storage tank. I don’t want to heat my collectors during winter, but I’m glad if 30°C (54°F) comes from above in winter so I don’t have to heat the full 75°C (167°F).
Does anyone know this problem?
Can anyone help me figure out how to solve it?
This is my first house, and I’m not a tradesman, but something is definitely wrong here—I have enough technical understanding to know that. I can only imagine this is caused by thermosiphoning, like in an old gravity heating system. When the fluid is warm enough, it rises on its own without the pump running and continuously cools down my storage tank.
Regards,
Alex
Last year, my wife and I bought a house. It’s not a new build but an older detached house that has been modernized several times over the years.
We have a combination boiler that runs on wood and pellets. There is also a solar thermal system on the roof, but it was only connected this year. Apparently, there were problems with the system and the heating technician was unavailable for a long time.
The system has been working very well all summer so far. I haven’t had to use any additional heating. In the past, there were a few days with very gloomy and rainy weather, so I had to add heat after about three days.
During this time, I noticed that my heating energy was being transferred to the solar collector. Of course, I discussed my suspicion with the installer, but he said that if the pump is off, no circulation is possible.
Over the weekend, my neighbor and I inspected the piping system and discovered a shut-off valve. Yesterday, I ran an experiment using this valve, which went as follows:
Yesterday at 9:30 PM, without any sunlight, the temperature on the collector’s upper sensor was 73°C (163°F). I closed the shut-off valve installed on the collector feed line. This morning at 6:00 AM, I checked again, and the upper sensor showed 16°C (61°F). I reopened the shut-off valve and went for breakfast.
After 30 minutes, before leaving for work, I checked again and, without any sunlight, the upper sensor suddenly showed 66°C (151°F), even though the pump was still off.
The pump normally only starts when there is a temperature difference of 5°C (9°F) between the lower and upper sensors.
Where do 50°C (90°F) come from in 30 minutes if not from the sun? It can only be coming from the storage tank. I don’t want to heat my collectors during winter, but I’m glad if 30°C (54°F) comes from above in winter so I don’t have to heat the full 75°C (167°F).
Does anyone know this problem?
Can anyone help me figure out how to solve it?
This is my first house, and I’m not a tradesman, but something is definitely wrong here—I have enough technical understanding to know that. I can only imagine this is caused by thermosiphoning, like in an old gravity heating system. When the fluid is warm enough, it rises on its own without the pump running and continuously cools down my storage tank.
Regards,
Alex
Good morning,
In the picture, you can see (the upper arrow) what I can turn. This causes the collector to cool down overnight. That’s how I performed the test.
The lower arrow points to the flow meter.
It is correct that the collector cools down at night in summer to prevent stagnation or damage. However, I noticed this on "cold" days when, after three days, I had to start heating and the collector showed 77°C (171°F), even though it was heavily overcast all day.
I just want to avoid heating my collector in winter because then it loses its value for me. On sunny winter days, I would like to get around 30°C (86°F) from the top and only heat the temperature difference.
You could also close the valve, but what if I’m at work and the sun suddenly comes out (you can’t really trust weather forecasts)? Then I would constantly have to open and close it.
I think there must be a way for the collector to cool down at night during summer but keep the temperature in the storage tank in winter without unintentionally releasing heat.
I only became skeptical when my installer said that it couldn’t be possible.
In the picture, you can see (the upper arrow) what I can turn. This causes the collector to cool down overnight. That’s how I performed the test.
The lower arrow points to the flow meter.
It is correct that the collector cools down at night in summer to prevent stagnation or damage. However, I noticed this on "cold" days when, after three days, I had to start heating and the collector showed 77°C (171°F), even though it was heavily overcast all day.
I just want to avoid heating my collector in winter because then it loses its value for me. On sunny winter days, I would like to get around 30°C (86°F) from the top and only heat the temperature difference.
You could also close the valve, but what if I’m at work and the sun suddenly comes out (you can’t really trust weather forecasts)? Then I would constantly have to open and close it.
I think there must be a way for the collector to cool down at night during summer but keep the temperature in the storage tank in winter without unintentionally releasing heat.
I only became skeptical when my installer said that it couldn’t be possible.
