FIXED... Read all the above, then went back to the heater and dug deeper and found a screen inside an on/off fitting. Took that out, cleaned, reinstalled.. So after all my talk about "de-scaling," just cleaning the filter improved the heater to 80% of a new one. Sounds like de-scaling is only useful if you get mold or so, ours doubtfully ever was descaled, certainly hasn't been in two years. Appreciate all the input on here.....