Water has already been refilled into the heating system. A little later the pressure reading falls again. It is no longer just about the last displayed value, but about a recurring pattern. Use this pattern as the basis for an appropriate professional investigation, rather than scheduling refilling as an unlimited everyday routine.
Pass on the repetition as concrete information
The manufacturer Viessmann names a renewed pressure drop shortly after refilling as a possible indication of water loss and refers to a heating specialist company for investigation. The source describes various possible causes. [DRUCK] This article does not diagnose a leak or a specific defective component of your system from that.
Our editorial recommendation: When contacting a specialist, describe the chronological sequence. When was the system refilled, by whom, and what has been reliably known since then? Reproduce existing readings or messages as accurately as possible, without yourself specifying an allegedly correct setpoint value for every heating system. A remark such as “it was less again soon” may remain recognisably imprecise.
Separate observation from own interventions
Mention other reliably observed anomalies such as a displayed fault or already known damp spots. This does not involve opening housings, searching for pipes or subjecting systems to pressure. If there is an acute water leak or a danger, appropriate assistance takes precedence over a complete chronology.
Do not let earlier measures disappear from the enquiry either. Bleeding, refilling and the most recent specialist work carried out can be named as known events, without deriving a cause from them yourself. No one should, on the basis of this article, operate valves, check components or establish an unknown filling connection.
Ask for a cause and an appropriate further course of action
Ask the responsible heating specialist to examine the recurring pressure drop. Ask which investigation is envisaged for the specific system and what you should bear in mind until clarification. An individual operating instruction cannot be replaced by a general internet value.
If a measure is carried out, have the findings made and the scope of the work explained to you in understandable terms. Which observation should be reported later and which follow-up question remains open? A single subsequent higher reading does not in itself prove that the recurring cause has been conclusively resolved.
Fictitious case: The third brief improvement does not amount to an explanation
An owner has repeatedly had the system refilled. After a short improvement the reading falls again. He compiles the known time points and earlier work and now explicitly requests an investigation of this pattern. Which cause is determined and which repair is appropriate remains open until the professional finding.
Keep the feedback and the related instructions. The result is a comprehensible approach to a concrete recurring fault. It is not a refilling, bleeding or repair instruction and it is not an invitation to continue unsafe operation for the sake of observation.