Common failures and causes:

(1) The control valve does not act. Symptoms and causes are as follows:

A. No signal, no gas Source: ① gas source is not open. ② because the gas source contains water in the winter ice, resulting in duct congestion or filter, pressure reducing valve plug failure. ③ compressor failure. ④ gas source mains leakage.

B. Gas source, no signal: ① regulator failure. ② Signal Tube leakage. ③ Locator Bellows leak. ④ adjustment mesh diaphragm damage.

C. Locator No gas Source: ① filter plug. ② valve failure. ③ pipe leaks or jams.

D. Locator gas source, no output: the throttle hole of the locator is blocked.

E. Signal, no action: ① Valve core off, ② spool and valve seat card die. ③ stem is bent or broken. ④ seat valve core freeze or Coke block dirt. ⑤ Actuator Springs are rusty for long periods of time.

(2) The action of the regulating valve is unstable, the symptom and reason are as follows:

A. Gas source pressure instability: ① compressor capacity is too small. ② valve failure.

B. Signal pressure instability: ① control system time constant (T=RC) is not appropriate. ② regulator output is unstable.

C. Air pressure stability, signal pressure is also stable, but the action of the control valve is still unstable: the ① locator of the ball valve by the dirty wear is not strict, gas consumption will produce output shocks. The nozzle baffle of amplifier in ② locator is not parallel, and the baffle cannot cover the nozzle. ③ output pipe, line leakage. ④ actuator rigidity is too small. The friction resistance in the ⑤ stem movement is large, and the phase contact part is blocked.