WH signal ?
 

WH makes a signal .. pumping his arm upwards , palm up . what is the signal for? is this a legit signal ?

Reset the play clock to 25 seconds.

And if he did so with both arms, it would indicate that the play clock should be set to 40 seconds, but otherwise the same signal. I don't think either signal is shown in the official football signals chart, but the mechanic is described in the rules.