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System Vacuum Leak Test

With the C-4144 or C-4315 tester connected in the system, tee in a vacuum gauge at the in-line connector in the orange vacuum hose near the vacuum transfer switch (this hose is connected to the master switch).

  1. With engine running, depress "LO-AUTO" pushbutton and rotate tester mode knob to heat. Allow vacuum gauge to buildup to at least 18" of vacuum and stabilize.
  2. Turn engine off and observe vacuum gauge leak down for one minute.
  3. If vacuum did not build up to at least 18" of vacuum or if vacuum leak down rate with engine off exceeds 5" of vacuum per minute, there is a vacuum leak in system. Check for leaking or disconnected hoses.
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