... -2008 EN12975,Solar Keymark certification Solar water heater tank features:1. Water tank shell:SUS304 food grade stainless steel2. Welded by ... installed within solar collector tank5. Copper coil heat exchanger inside tank provides more than 1.2m2 of heat transfer area6. ... inside solar collector tank7. No water is introduced into tank(apart from occasional topping up),so corrosion and scale buildup ...