Line diameter has exactly zero effect on vacuum, and "bigger is better" where a hydrovac system is concerned, so the system can flow sufficient volume.
Jerry
Jerry, I included that info for oldieoldie, if the 1/2"od copper is used, he won't have to make any special reducers or fittings, the original steel line is 1/2" od. 1/2" refrigeration soft copper is 1/2" od. 1/2" od hard copper is available but unless he has contacts in the building trades, he may have to purchase a 10' stick.
