hilo now included

AG1 to activate in alert
AG2 to activate in attack
AG3 to activate in hilo

decided i would make a 3T22 right after the 2001-SRNB and this is the result.

CONTROL TIMING:

ATTACK

On: 7
Off: 7

HILO

Hi: 0.6
Lo: 0.6

The Model 3T22 is equipped with 2 solenoid-operated butterfly valve dampers, one in each intake. When the solenoids are energized, the dampers slam shut, restricting airflow to the chopper and greatly reducing its sound output. When the solenoid is de-energized, a return spring forces the damper back into the open position, allowing air to flow through again. When the two dampers alternate between open and closed while the siren is running, this creates a "hi-lo" signal. The dampers are also capable of operating in unison, creating a "pulse" signal. When the siren shuts off, both dampers automatically de-energize and open.

If the dampers are not maintained properly, the return spring can fail, causing the damper to be sucked shut when the siren activates which prevents the rotor from reaching its full volume. The solenoid mechanisms themselves can also become seized if they aren't maintained or used regularly. Because the dampers are very infrequently used nowadays, it can be very difficult to find a 3T22 that has both dampers working. Most fire departments who own 3T22s have ceased running the hi-lo signal for fire calls, instead running the attack signal instead.