Keep in mind the WFCO Power Distribution Unit consists of all your 120VAC circuit breakers and 12VDC fuses. The WFCO original installed WF series converter which I think I understand now has been pulled out and replaced with a PD brand converter/charger unit.
The 9 year old WFCO mainframe is only a power management distribution unit and has nothing to do with the mounted PD converter except to provide a mounting space in the lower compartment and 120VAC power to operate it.
If you are not getting 13.6VDC at the + and - battery connections when on generator or shore power then the PD unit is bad or the path between the converter/charger to the battery is OPEN CIRCUIT.
There is only two sets of fuse controls between the output of the PD Converter unit being two REVERSE POLARITY fuses mounted on the WFCO Power Distribution Panel labeled REVERSE POLARITY and an IN-FUSE situated very close to the BATTERY POSITIVE terminal. You can see in the drawing below where the two REVERS POLARITY fuses are located on the WFCO 12VDC distribution board. These are the two FUSE OFFSET from the other fuses and located just above the word POS where my 12VDC is feeding the BATTERY connections. I think the PD also will have a set of REVERSE POLARITY fuses built-in the PD front panel. Not sure which set of fusess you have checked. About the only thing that will blow the REVERSE POLARITY fuses is actually hooking the BATTERY TERMINALs in reverse order - just takes one spark to do it.


sample photos from google images
Clarify how you are presently hooked up now...
When I upgraded my WFCO 8900 Series Power Distribution Panel I left the WF8945 Converter/charger inplace since it was brand new and mounted my smart-mode PD9260C Converter/charger at a different location closer to the battery bank.
My WFCO Power unit was new and I was having problems getting its WF8945 to go into smart mode charging. I added the PD9260C Converter/charger to the system that I know will go into smart-mode charging when needed (both AUTO and MANUAL).
I actually can run either converter/charger now by flipping the 120VAC circuit breaker for the unit I want to use. This adds to my PLAN Bs for having a back-up converter/charger unit...
This is simplified drawing of my setup...

just my thoughts
Roy Ken