It is our first heating of the season.
Our domestic hot water has run from June till now without any issues, flow rates were higher than now. After switching on the HK1 on 24th of october, the flow was ok. On 26th, there was a strange curve (see attached).
Since then, the flow rate has dropped significantly for both HW and DHW.
Currently, on DHW, the flow is around 214l/h to heat up a 200 l buffer (vitocell 100-V).
Setting for DHW pump: 60%, but only runs at 10% according to the display.
For heating all underfloor heating: 96 m² downstairs on a 9 loop manifold, all acuatators fully open and 13m² upstairs (bathroom) directly connected to main flow and return.
Flow only reaches 300-340 l/h, way too low for this heating system. The flow was higher before and has consistently dropped. Setting is 90%, but only reaches around 11% pump speed. There is some noise at the indoor unit. Additionally, we saw some water in the indoor unit (on the left (top and bottom).
What could be the cause? Our heating engeneer will come together with the viessmann expert next week to check.
Any tips or recommendations to check?
VITOCAL 250-A AWO-E-AC 251.A04-16
underfloor heating 13 m² upstairs bathroom directly to flow & return + 96 m² downstairs (9 loop manifold)
