V
Vermilli0n13 Dec 2022 16:40Hello everyone,
I’m really at a loss and would appreciate any input.
The heating system (4 floors: ground floor with underfloor heating, basement and 1st/2nd floors with conventional radiators) is a gas condensing boiler system. (Photo of the boiler room attached). After purchasing the house in mid-year, the underfloor heating was briefly put into operation in October and appeared to work well. A walkthrough of the system by the installer was done recently, and the settings on the wall-mounted control unit Junkers Ceracontrol were checked.
The current problem is that there is no flow reaching the individual circuits. The conventional radiators heat up without any issues.
What has been done so far?
- Checked the actuators and the valves underneath (both working perfectly; no flow even with actuators removed and valves fully open)
- Replaced the old pump (Grundfos Alpha+ 25-40 180) due to insufficient performance (shaft was seizing repeatedly and there was heavy buildup). The new model Grundfos Alpha2 25-40 180 shows a flow of 0.0–0.1 m³/h (0.0–0.1 cubic meters per hour) regardless of the setting. (Correct installation has been confirmed)
- Flushed and vented the individual heating circuits. Shortly after the first flush, the flow meters showed between 1.5–3 L/min (liters per minute) depending on the circuit, and the pump showed 0.5–0.7 m³/h (cubic meters per hour). After a few seconds, these values dropped back to 0.0–0.1 m³/h and the flow meters indicated no flow again.
I’m running out of options and hope someone might have an idea. If more information about the system is needed, I’m happy to provide it.
Many thanks in advance for your help!
I’m really at a loss and would appreciate any input.
The heating system (4 floors: ground floor with underfloor heating, basement and 1st/2nd floors with conventional radiators) is a gas condensing boiler system. (Photo of the boiler room attached). After purchasing the house in mid-year, the underfloor heating was briefly put into operation in October and appeared to work well. A walkthrough of the system by the installer was done recently, and the settings on the wall-mounted control unit Junkers Ceracontrol were checked.
The current problem is that there is no flow reaching the individual circuits. The conventional radiators heat up without any issues.
What has been done so far?
- Checked the actuators and the valves underneath (both working perfectly; no flow even with actuators removed and valves fully open)
- Replaced the old pump (Grundfos Alpha+ 25-40 180) due to insufficient performance (shaft was seizing repeatedly and there was heavy buildup). The new model Grundfos Alpha2 25-40 180 shows a flow of 0.0–0.1 m³/h (0.0–0.1 cubic meters per hour) regardless of the setting. (Correct installation has been confirmed)
- Flushed and vented the individual heating circuits. Shortly after the first flush, the flow meters showed between 1.5–3 L/min (liters per minute) depending on the circuit, and the pump showed 0.5–0.7 m³/h (cubic meters per hour). After a few seconds, these values dropped back to 0.0–0.1 m³/h and the flow meters indicated no flow again.
I’m running out of options and hope someone might have an idea. If more information about the system is needed, I’m happy to provide it.
Many thanks in advance for your help!
No idea. But a systematic approach helps with all problems. I would first turn off everything that is still running in the system (so switch off all conventional radiators completely). Doesn’t the pump have a display at the front showing the wattage? Mine does... Maybe the water is finding the path of least resistance?
Similar topics