I have galvanized fittings for the hot and cold lines on the 50 gal electric water heater the only fittings I could find at home depot to connect to my existing cpvc pipe was a copper to cpvc 3/4 fitting. I used Teflon tape on the threads and this union leaks. I re-did them twice. is there a fool prove way to attach these fittings? I have replaced water heaters twice before but not with cpvc plumbing lines.