2018 ROADTREK ADVENTUROUS CS SOLAR/LITHIUM ALDI electric and diesel heat. Heat works as does hot water: using either electric or diesel BUT HEAT is weak! hot water is good. I set desired temp at 86F, but can only maintain +17F over outside temp. Night time outside temp below freezing but not below 25F. So 43F in RV. Do I have t bleed it? Anti-freeze/coolant tank for heat OK and it does bubble etc. All electric RV, Solar, Litium, and diesel heat. No propane.