When installing my system, I didn't feel the need to install a big float type bleeder.
(The bleeder goes on the roof at the highest point in the plumbing, where an air pocket might form).
Instead I used the cheap and durable type.. That might last forever.
Instead of a few years. A unit that was easy to cover with installation.
After the glycol fill, I used a 2-way to tell my wife in the basement to turn on the pump,
while I was on the roof using a screw driver to bleed the air out.
After a while, the air was all gone and the pressure was good.
After a few years, I climbed up and just cracked the screw a tad and got no hiss, but pure glycol mix..
I was glad that I didn't use the float type. I changed about 4 of those on my
boiler, before installing a manual bleeder with a copper hose.
(Ice maker kit screwed right in).