The valve on the blue IS the cold water low point drains and is connected to a cold water line of the system. The valve on the red IS the hot water low point drain and is connected to a hot water line of the system and does not drain the water heater. To drain the water heater the plug or anode rod (depending on brand of water heater) must be removed.
The valve (and there may be more than one) coming from the fresh water tank operate at allowing water through them when the handle is parallel with the water line and stops water flow through when the handle is perpendicular to the water line.
One valve will drain the tank and one (if equipped) will be before the water pump.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7