baxi due tec lossing water

[erj]

hi as above baxi due tex needs toping up every other day, PRV not passinf nothing running down the con pipe, in a bunglow so all pipe are eather in the loft or in the wall nothing under ground, any one any thoughts l;ost for what to check next.

 

[Billy Bob Bob]

isolate the boiler via the isolation valves leave the boiler off for one day if pressure holds its not the boiler

 

[tipintim]

Is the auto air vent in boiler passing?
Slight leak on a lockshield valve?
Automatic air vents in attic leaking?
Because it needs topping up every other day , it sounds small and evaporating on hot pipe work. IMHO