Why is vacuum on all the time at heater valve?

Yes, its me again but now the vacuum won't turn off, so I made another post in order not to confused anyone. Previous to this, I found the vacuum line disconnected at the vacuum reservoir. I guess I accidently dislodged it when I was installing new heater hoses. But when I attached vacuum line, I noticed vacuum now is always on which means when I tried the A/C, hot air blows in. (Only A/C vents work, so when I put on heater, heat comes from A/C vents which is fine with me.)

As I...

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