Hello,
we have a somewhat complex problem and are currently unsure about what to do. Any experiences would be appreciated.
Our house is 23 years old, with a Buderus boiler and control system; the burner was recently replaced. In our living room, there was a kind of "thermostat" that was already broken when we bought the house. We naïvely accepted the sales advisor’s statement that it wasn’t needed and assumed that the heating could be controlled directly at the unit downstairs.
We suspect that something was set up about 23 years ago, after which no one cared about this thermostat, and eventually, it just broke. The water may be a bit cooler, and our bathroom radiator never really gets warm despite bleeding and unblocking. Otherwise, everything is fine for us. When my husband goes into the living room around 7 a.m., it’s still a bit cool, but absolutely okay, and when I come home in the afternoon, it’s warm in there. So far, so good.
Now, we have rented out our granny flat to a young woman for 8 weeks. There is only one heating circuit. Due to her work, she gets up at 4:30 a.m. This was not a problem before, but since last weekend it seems that the flat is freezing cold when she gets up in the morning. Previously, according to her, this was different, and the heating was running in the morning. Now it isn’t anymore. She feels cold and wants this changed, which I can understand.
Today, a technician was here. The problem is: this control unit is broken. The heating is set to something, the sensor is located outside on the north side, but exactly what was set can no longer be read or changed.
The young woman now wants the heating to be set so that it is warm at 4:30 a.m.
Because we have only one circuit, we cannot separate the systems for the granny flat and the main house. This means we would have to set it so that the radiators start heating at 4:30 a.m. for ourselves as well. This makes no sense for us—no one here gets up before 6:30 a.m., the children get up about an hour later, and we may not be as sensitive to cold.
But to do this at all, a new controller is needed. These parts from 25 years ago are no longer available today—you can get “refurbished” ones from various online shops for around 300 euros, but whether we can still set those ourselves is questionable.
The alternative would be a completely new heating control system, which would cost about 1500 euros; a binding offer will be made. That is certainly even more expensive 🙂
For us personally, everything is basically fine, so this is a lot of money. On the other hand, it may also not be very sensible if you have no way to adjust your own heating, and sooner or later, one might have to invest in this anyway?
we have a somewhat complex problem and are currently unsure about what to do. Any experiences would be appreciated.
Our house is 23 years old, with a Buderus boiler and control system; the burner was recently replaced. In our living room, there was a kind of "thermostat" that was already broken when we bought the house. We naïvely accepted the sales advisor’s statement that it wasn’t needed and assumed that the heating could be controlled directly at the unit downstairs.
We suspect that something was set up about 23 years ago, after which no one cared about this thermostat, and eventually, it just broke. The water may be a bit cooler, and our bathroom radiator never really gets warm despite bleeding and unblocking. Otherwise, everything is fine for us. When my husband goes into the living room around 7 a.m., it’s still a bit cool, but absolutely okay, and when I come home in the afternoon, it’s warm in there. So far, so good.
Now, we have rented out our granny flat to a young woman for 8 weeks. There is only one heating circuit. Due to her work, she gets up at 4:30 a.m. This was not a problem before, but since last weekend it seems that the flat is freezing cold when she gets up in the morning. Previously, according to her, this was different, and the heating was running in the morning. Now it isn’t anymore. She feels cold and wants this changed, which I can understand.
Today, a technician was here. The problem is: this control unit is broken. The heating is set to something, the sensor is located outside on the north side, but exactly what was set can no longer be read or changed.
The young woman now wants the heating to be set so that it is warm at 4:30 a.m.
Because we have only one circuit, we cannot separate the systems for the granny flat and the main house. This means we would have to set it so that the radiators start heating at 4:30 a.m. for ourselves as well. This makes no sense for us—no one here gets up before 6:30 a.m., the children get up about an hour later, and we may not be as sensitive to cold.
But to do this at all, a new controller is needed. These parts from 25 years ago are no longer available today—you can get “refurbished” ones from various online shops for around 300 euros, but whether we can still set those ourselves is questionable.
The alternative would be a completely new heating control system, which would cost about 1500 euros; a binding offer will be made. That is certainly even more expensive 🙂
For us personally, everything is basically fine, so this is a lot of money. On the other hand, it may also not be very sensible if you have no way to adjust your own heating, and sooner or later, one might have to invest in this anyway?
Buderus heating boiler according to DIN 4702
Type G115-21
Year of manufacture 1995
Construction approval number 06-226-352
DIN regulation 3 R 054/92
Heat output 17-21 kW
Thermal load 18.4-23.0 kW
Boiler water content 33 liters (8.7 US gallons)
for flow temperature 110 degrees Celsius (230°F)
Does this help?
Type G115-21
Year of manufacture 1995
Construction approval number 06-226-352
DIN regulation 3 R 054/92
Heat output 17-21 kW
Thermal load 18.4-23.0 kW
Boiler water content 33 liters (8.7 US gallons)
for flow temperature 110 degrees Celsius (230°F)
Does this help?
Musketier schrieb:
Are these radiators or underfloor heating?
If they are radiators, do they have individual thermostats?
If a thermostat is present, I would simply replace it with a programmable one.
By the way, wasn't it said that night setback could even lead to increased consumption?These are radiators from 1995. Without thermostats. According to the installer, it is not possible to install thermostats on these radiators.
Did the defective control unit (thermostat) look like this?

From the boiler’s user manual:
…If no remote control is connected, you can set your room temperature for normal heating mode (day mode) and reduced heating mode (night mode) directly on the control unit.
If two heating circuits without remote controls are connected, the settings on the control unit apply to both heating circuits…
As expected, adjustments on the heating device are indeed possible, even without a room temperature controller.

From the boiler’s user manual:
…If no remote control is connected, you can set your room temperature for normal heating mode (day mode) and reduced heating mode (night mode) directly on the control unit.
If two heating circuits without remote controls are connected, the settings on the control unit apply to both heating circuits…
As expected, adjustments on the heating device are indeed possible, even without a room temperature controller.
No, the thermostat looks different.
It says Buderus Ecomat 4000 on it, and you can press different buttons. This device was mounted on the wall, and there is a cable going into the wall. However, the device was dead, and at the bottom, you can click it into this blue control box, but nothing happened. That’s why, as I understood the technician, nothing can be adjusted anymore.
I will send my husband to the basement later with this picture again. I just went down and wouldn’t know where to make any adjustments on the boiler.
And we only have one heating circuit.
But if it were possible to adjust anything there, you should be able to set the time and temperature, right?
It says Buderus Ecomat 4000 on it, and you can press different buttons. This device was mounted on the wall, and there is a cable going into the wall. However, the device was dead, and at the bottom, you can click it into this blue control box, but nothing happened. That’s why, as I understood the technician, nothing can be adjusted anymore.
I will send my husband to the basement later with this picture again. I just went down and wouldn’t know where to make any adjustments on the boiler.
And we only have one heating circuit.
But if it were possible to adjust anything there, you should be able to set the time and temperature, right?
Mizit schrieb:
but you certainly can’t retrofit a separate heating circuit, right? Or only for an extremely high cost?It depends on how the system is currently configured (I mean which pipes run where). But generally, separating by floors is usually possible without much trouble.
So you had this one here:
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