Here is my thinking my car has all silicone heater hoses and cap on that car is 18 PSI its got 83,000 miles on it there original . Now boiler never going to torch er a hose as much as on a car . and think of a motor home with 454 and pulling 13,000 lbs all the time and they don't have silicone hoses either I know with air conditioner on temp will hold 200f for hours on end .. temp up and down is harder on them than like a semi just hot all the time . also to make a person think I had to change heater hose in 1978 took off original heater hose gm clamps on motor home in 2003 . the rubber had to be scraped off all connections just baked on never leaked hard as rock at 120,000 miles . Van style you know how hot them get daully model. there was vacuum lines that turn to dust if you rubbed them in your hand lol . never seen anything like it . lots traveling to southern states also. myself I was surprised more guys don't use silicone heater hose on there boilers . You could put steel bradeing on if you think a critter would chew on them would be the only issue I can think of I seen chipmunks do some crazy chewing when there freaked out LOL
Heat550