CJW8 wrote:
I understand that manufacturers take shortcuts but usually not on propane systems due to the liability. If they used hose, it is probably because it is in an area where vibration or flexing could occur. I would not replace with copper tubing. Soft copper will fail under vibration or flexing.
I thought about this, and I think this is one of gray areas. There isn't much flexing between the A-frame of hitch and the rest of the frame. Not sure that soft copper could fail under vibration either, haven't heard of this. Stress is a different matter, but where there is no flex, there is no stress.
There "could" be flexing on the regulator end, if it's not mounted properly on the A-frame - they often put it on a flimsy 1/4" thin metal rod. This is the spot that I would have a good look at, if copper tubing is to be used. Make a stress-absorbing loop on that copper tubing - they do this on appliances copper tubes under the frame where stress is a concern.
There also "could" be damage from flying rocks on the road, where rubber hose would flex but copper would be damaged - but then, you already have half a dozen of copper tubes under the frame where it connects to appliances. They don't use rubber hose on those - but they sometimes put plastic cover on copper tubing, to protect it. Btw, I put plastic cover on my rubber hose from regulator to trailer, to protect both from UV and abrasions.