I read every word in that competitor's installation guide that Andy posted.
There are many errors and omissions in it. Some errors are really bad!
I could copy/paste them but since they are a competitor, I won't. I'll just feel bad for their Clack WS-1 customers.
They have revised a guide used for Fleck to fit the Clack WS-1. The fit isn't very good.
I don't know fer sure but, IIRC, silicone and sch 80 pvc may not mix well, yet they are telling their customer to use silicone with sch 80 PVC. I do know there is no need for lubricant on the o-rings on the plumbing connectors.
Anyway, silicone o-rings do not need any lubricant but water works very well.