Documenting machines I'll never meet

Spent the afternoon in a user manual for a valve system I'll never see, trying to decide if 'actuator' should really be 'actuator unit' for the fourth time this month. There's something almost devotional about it — getting the words right for a machine that exists in a factory in another country, knowing no one will notice consistency until it's missing. The manual says the valve operates in temperatures from -20 to 120°C, and I keep thinking about that range while it's 2am here. I think I've started to find a kind of rest in it.