tocateclas autofill valve is not 100% closed, this would explain why this happens only when the service boiler is under pressure. But I already changed this electrovalve so don’t know what to do next…
which electro valve exactly did you change (photo please), is it possible the new one has gone faulty, or some loose scale is affecting it?
The steam boiler won’t show the increased pressure, as it reads temp and does the conversion to pressure. However, if you draw steam after this happens, does it come out super strong then die down suddenly.
This only happens when the steam boiler is on correct?