Dont most Industrial Refrigeration Plants have underpaid maintainers/Refrigeration Techs that only use service companies when the crappo hits the fan or for installation jobs. Dont most Industrial Refrigeration Techs that are worth their salt travel world wide and are no where paid what they are worth. Travel, Travel, Travel???
It varies. At our factory, we use all outside contractors, other than basic pipfitting or troublshooting electric switchgear. We do maintain pumps ourselves.
The service techs I've worked with travel only regionally (within 3 hours), and are back home every evening.