Take this to NCAT.
The principle you take them on is that they did not apply the by laws equally.
There was a case settled late last year ( and I can’t recall the particulars) but an elderly couple won their case because the owners corporation was applying a bylaw to them but not to other owners.
Generally courts apply the principle that if you turn up, you have to have “clean hands”
The OC will be forced either to make the other owners remove their condensers from in front, or approve your installation.
I’d suggest using a strata lawyer in this case as it’s a sort of roundabout argument and you need to get your complaint worded correctly so that the correct orders can be made.