CH system is loosing pressure - drops from 1bar to zero over ~7days.
Sime 100c combi boiler.
So far, in no particular order;
No signs of any leaks within the boiler itself.
Replaced the PRV and had a bucket under overflow to double check PRV is holding - no leaks.
Checked the CH...
Hi, long time listener first time caller...
Sime Format 100C combi boiler. 5 years old, serviced annually, runs perfectly 99.9% of the time...
...when the outside temperature drops down to near freezing it develops a strange quirk.
With demand from either DHW or CH the boiler fires up...