Question about Monoflo Tees

[anvilman]

A few months ago I replaced all my old black iron piping in the basement that fed cast iron baseboard on the floor above with 3/4” oxygen barrier pex. As part of my basement renovation it had to be removed and relocated as it was rusty and was hanging below the joists. I installed the pex in the same configuration as the black iron all with 3/4” pex including the supply and return for each room. I believe my system is considered a one pipe system. The line from the boiler makes two loops that both feed back into the boiler. From those loops there is a supply and return for the baseboards on the floor above in each room. I made a mistake in not researching enough and install the entire system without any Monoflo tees. However, the system had been up and running for a few months now and it seems the system is running completely normal. Every baseboard in the house gets very hot as they did previously. Once I realized the Monoflo tees we’re not installed I went back and looked at some old pictures I took of the basement before I started the renovation and looked at some of the pipes, and noticed that there were certainly monoflo tees on the black iron. I don’t notice anything different about the system as far as how it performs. The house gets up to temperature just as fast as it did previously the best I can tell. So there are no Monoflo tees whatsoever, only normal tees. About a month and a half ago one section of baseboard cracked open and spewed water all over, luckily I was home and quickly turned everything off and isolated that section of baseboard which was in our bedroom. Then a couple weeks ago in my sons room another crack occurred but this time the crack was smaller and created a continuous drip, thankfully again I was home and quickly shut everything down and isolated that section. So I guess my question is do I need to install Monoflo tees where they are necessary before I finish the sheet rock? And also these cracking radiators have anything to do with having no Monoflo tees? Please refer to my link for video of my system.