I ask this because in my experience they never do. In fact they’re usually out the door in less than 20 minutes. Enough time to do a basic function and safety check. That’s it.
Before I took out the cover I did it myself, and it will need doing again. Most boiler manufactures advise expansion vessels to be re-pressurised at least once a year.
I previously made the mistake of allowing techs to fob me off about a small weep from my drain valve. I knew this was wrong but it kind of encouraged me to stupidly keep topping up the pressure every couple of months. Eventually the weep became a heavy leak and my entire manifold had to be replaced.
The cover is great and gives me peace of mind, but the lack of proper maintenance is a bit of a disappointment.
