The pex al pex might be preferable for you. I'll take back my initial comment about that for say kind of in the eye of the beholder. But the are people who are weary of pex al pex becuse of delamination
cast iron radiators need a supply temperature of 140 degrees f,
copper fin radiator need a supply temp of 180 -190 degrees f
what will happen is that area with the old cast iron rads will be very warm as the water temp rises.
however the area with the copper fin rads will not be producing any heat.
I have seen this very often , you can not substitute copper fin for cast iron.
I wasn’t planning on mixing the two. I was planning on using Runtal radiator to replace one of the old cast iron radiators. The other two will be replaced with beacon Morris kickspace heaters. One had already been converted previously and one will soon be converted.
No downside to soldering. It the only way it was done for years. It's the preferable way. You just want to flush the pipe and you only need a tiny amount of flux... Tiny. People use way too much flux. You should have to look close to see that you fluxed the surfaces.
Watching this thread as I’m considering Uponor HePEX for home runs to new Runtals. Both Runtal and Uponor has has a 200 degree rating. Is the concern with using HePEX degradation or is the concern movement?
I'm planning to run the Runtal's lower than 180, but will set the upper limit on the boiler at 180 for sure.
Thanks, good info on the flux too. The flux is dripping everywhere on my old pipes and I understand that excess can cause problems with the joint. The way it looks I may end up replacing most of those pipes.
Appreciate the tips on flux as well- I’ll be using a 1/2 sweat to propex adapter that’s brass. I too will have my aquastat- hydrostat set to around 175.
On another note- I cannot find baseboard bleeder elbows with propex fittings. I need one of these on each of my kickspace heaters.
I got creative and purchased these ball valves with bleeders instead of having to sweat baseboard elbows onto propex adapters. Any issue with this route? These full port ball valves are perfectly safe in closed loop heating systems correct?
Let me know if something like this would be as good as a traditional elbow. I’d have the valve oriented as it sits in the photo with the bleeder facing up right before the Pex drops down into the basement. Any concern with the bleeder facing up as opposed to to the right?
I can always get the item you suggested and just sweat on a 3/4” copper to 1/2” propex