... toppest manufacturer of 58*1800 solar bolier,solar water heater with CE,Solar Keymark,CCC 1.Products series ... ,outer skin,end cap and insulation layer form a perfect heat-preserved cabin,the rate fo air ... 4 holes for exhaust port, overflow, water inlet and outlet, electric heater is optionWelding:Argon arc weldingFastening pieces: ... of 58*1800 solar bolier,solar water heater with CE,Solar Keymark,CCC