So Far No Issues

Wow! 85 psi!? I use 40 - 45 psi and check each valve at least twice until no moisture forms on my fingers each time. I have no need to test the suggested 40 psi water pressure limits. Have done that for years with various TT's and it's worked in NE OR winters that routinely get into minus double digits Fahrenheit.  Along with pink stuff for the p-traps, toilet of course. Always learning something on this forum!

Originally posted by jato And the beauty of blowing out is once the HW tank is drained and the 3 valves are set to bypass it takes less than 2 minutes to blow all the lines out twice using air at 85 psi.  Works for us.

Jato, Jato, Jato, what's with the $200 per hour?  I charged that back in 2000 before I got out of the litigation business and decided to do something honest for a living.  Now that I'm retired, my hourly rate is priceless, coffee breaks being extra.  

A 3 pack of Hepvo drain traps costs $157 on Amazon; one for the each sink and one for the shower.  To make it cost effective, I'd have to have the trailer over 40 years just to pay for the Hepvo drains, not to mention the other plumbing parts to make it fit and my incredibly valuable labor.  With all due respect to Forest River, I don't think my trailer will be around that long.

We have also used the blow out method and it has worked well with one exception; the toilet valve had some residual water in it that froze and cracked it, making an unpleasant surprise on the first trip of that season.  I replaced the valve with a more durable one made by a third party company that claims it resists freezing better than the Dometic valve.  I also make it a practice to disconnect the water line to the toilet valve when I blow out the system and separately blow some air through the toilet valve while holding it open.  All you need is a towel to soak up the little bit of water that spills out onto the floor.