4 ms·
Filled circle means "vent is blocked, so no air can pass". Empty circle is an unblocked vent through which air can pass.
by Slartie 7y ago
Filled circle means "vent is blocked, so no air can pass". Empty circle is an unblocked vent through which air can pass.
- gmac 7y agoI think the problem is those meanings can plausibly be reversed, so it's hard to remember which way round it goes. A better way to do it that I've seen is to represent air flow with wavy lines or similar on the 'open' symbol.
- alecmg 7y agoPretty sure in the last car it was the opposite. Filled circle meant air was coming. So you can see why this is confusing