John, Your timing couldn't of been better ! Yesterday I was examing this area on my unit. I have the HL sewer boom, it's kinda neat but the juries still out. I was looking to see how I could install a bayonet valve outside the cellar "IF" the cable valve/s start leaking. However, there's not much room. In addition by neccesity HL had to install a short lenght of flex hose to allow the boom to swing. Anyway, I'm still trying to figure out an easy way to do this without changing all the external piping. It's a challenge
The hot link you posted educated me a little more and also convinced me I need to look at doing this. Thanks, Tom