Regel 34: Game Timekeeper

The Game Timekeeper shall record the time of starting and finishing of each period in the game.
During the game, the Game Timekeeper will start the clock with the drop of the puck and stop the clock upon hearing the On-ice Officials’ whistle or the scoring of a goal.
The Game Timekeeper shall cause to be announced over the Public Address System:
(I) in the 1st and 2nd each period that there is (1) one minute remaining to be played in the period;
(II) in the 3rd period that there are two (2) minutes remaining to be played in the period.

Manual stopwatches should be available to determine the correct playing time in the event the timing system fails.
For more information refer to League Regulations.

For the purpose of keeping spectators informed as to the time remaining during intermissions, the Game Timekeeper will use the electronic clock to record the length of intermissions. The clock will start for the intermission immediately at the conclusion of the period. Intermissions are 18 minutes in length, unless otherwise defined.
If there are unusual delays for any reason, (e.g., altercation, arena installations, ice, or ice resurfacing problems) it is important to use discretion in starting the clock.
For more information refer to League Regulations.

In the event of Overtime for a regular season game, the Game Timekeeper shall reset the clock to five (5) minutes in preparation for the Overtime period. The Overtime period will commence following league Regulations.
→ Rule 84 – Overtime Operations

If the arena is not equipped with an automatic signaling device or, if such device fails to function, the Game Timekeeper shall signal the end of each period by blowing a whistle.

The Game Timekeeper shall signal the Referees and the competing Teams for the start of the game and each succeeding period and the Referees shall start the play promptly.
→ Rule 77 – Game and Intermission Timing
For more information refer to League Regulations.

Any loss of time on the game or penalty clocks due to a false “face-off” must be replaced as appropriate. The Video Review Operations may be consulted to ensure the time is accurately replaced.
In the event of any dispute regarding time, the matter shall be referred to the Referees for adjudication and their decision shall be final. They may use the Video Review Operations to assist in rendering their final decision.
→ Rule 37.6 – Video Review to verify Time on Clock

The Game Timekeeper shall assist to verify game time using an additional timing device (League approved stopwatch). In the event the clock fails to operate when play resumes, the On-ice Officials may elect to stop play provided there is no imminent scoring opportunity or wait until the next legitimate stoppage of play.
In cooperation with the Game Timekeeper and the Video Review Operations, the clock is to be re-set to the appropriate time.

In the event a Video Review shows a goal was scored prior to the play being stopped, the Video Review Operations will inform the Game Timekeeper and the Official Scorekeeper of the time of goal and the amount of playing time left to be reset on the Game Clock.