Welcome to our forum.
Who cares about a diverter valve warranty? You should be concerned with much bigger things than that when it comes to a warranty.
Wanted to add one additional note: According the Sundance’s website – the Marin uses the original MicroClean filtration. http://www.sundancespas.com/800Series/MarinSpecs.phpHowever, on a different forum it stated that spa is now using the MicroClean II. Can someone please confirm this?