Just put the PID in manual mode and then you can change the percent of power being delivered to the element. It is one of the really great features of your PID.
From the SYL-2352 manual.
4.2.2 Display change
Press the SET key to change the display mode. The display can be changed
between display modes 1 and 2.
4.2.3 Manual/Automatic mode switch
Bumpless switching between PID mode and Manual mode can be performed
by pressing the A/M key. The A-M LED will light up when the controller is in
Manual mode. In Manual mode, the output amplitude can be increased or
decreased by pressing ▲ and ▼(display mode 2).
Please note that manual control is initially disabled (A/M=2). To activate
the manual control, set A/M=0 or 1.