Otis 23 UCL Contorller F4C Fusing

Anyone know the correct size for the F4C fuse on a Otis 23UCL Controller. I found a 15AMP time delay here on a job and the insulation on the wires associated with this circuit are is begining to crack and melt and the wires were extremely hot. All other fuses on the terminal block are standard 10 AMP. I looked in the other controller on the job and it had a 6A standard fuse. The prints do not say what size fuse it needs. Pictures are attached.

Look on the back of the controller at the fuse block. Otis printed the original value of the fuse there.

F4C fuses will be max 6amp but will depend on the VA of the transformer.
What is the device that the TRM is driving.?