Hi Pat and Debbie,
Sorry to hear your trouble with the PCS.
Here's a link to all the documents for the PCS that we have in our archive of manuals.
The PCS has a Limp Home feature but I couldn't find any information about it. I think it puts itself in that mode if the controller logic fails.
I once had a similar issue as you. The problem ended up being a short in the AC power feed to the water heater at the metal junction box on the back of the water heater.
To make matters worse, before I found that short, I reset my 50 amp breaker and the breaker at the pedestal many times. In doing so, I caused 1 of the "current cups" to break (internally). This freaked the PCS logic out and it acted like yours is.
The repair for me was:
1. Repair short circuit
2. Replace PCS relay/logic board (current cups are part of the board)
This all said, I'm not saying you have a short circuit at your water heater - just letting you know what my issue was. I