Retrofit oil burner with LP?

Hi folks, I discovered that CPVC is for hot water (and cold) and PVC is only for cold water. Now, my hot water comes from the tankless coil in the oil furnace (boiler) and is therefore the same temperature as the hot water in the pipes for the baseboard heaters. Since the hot water in the drinking water lines is the same temp as the hot water in the heating pipes, is it true that I could use CPVC in the heating loop in certain places? I stand to gain several advantages: #1) It's very, very, very easy to work with and is flexible to a point; #2) It glues together in a few seconds vs. soldering and is foolproof (no leaks); #3) It's cheaper #4) since it's plastic, you'll get a certain ampount of insulation built-in. I checked the rating of CPVC and it says at 180 degrees it's good for 100 psi and the heating system stays at about 20-25 max. and the system would be set for 180 degrees. Anyone ever hear of this being done? If not, do you think it's safe to do? If you have any thoughts, please tell me "why." I need to learn principles, not just memorize yes/no answers to a certain situation. Thanks!!

I'm gonna be installing a Burnham IN5 steam boiler and need to constuct a hartford loop. My old dunkirk doesnt have this loop and not sure how to make one. i did google h-loop and have a pretty good idea but at the waterline it states to use a [B]closed nipple[/B] i have my water feed in the return line and with a closed nipple there wont be able to fill boiler? also with the bolier exhaust will i still need a draft door or with the automatic damper i wont need one? thanks.