I would like to rebuild the HWH air manifolds (6 packs).<br/><br/>Can the solenoid O rings be purchased from a local source or are they exclusive and must be ordered from HWH?<br/><br/>How much does HWH charge for replacement units?<br/><br/>Whats the best way to contact HWH if I need to order parts. I read about the long wait to get service advice, is parts ordering a simpler matter?