Secondary loops doesn't move the water

OK.  I admit I made a few changes.  I removed two radiators that come off one 1.5 set of pipes at the end of the two lines. I did not expect that to cause this problem because most of the radiators seem to come off the main "trunk" pipes in pairs that make their own individual loops, just like the radiator I just installed that had been removed, leaving two plugged pipes in our bedroom. 



Here's what I see as the important aspects of our setup regarding the flow:



- At 2" and a 1.5" return line merge into a 2" cast

- Downsize to about 1.25" copper (vertical going down)

- T with a boiler drain (vertical going down)

- 90 to horizontal

- Honeywell Supervent with an expansion tank on the bottom

- Ball valve (in open position)

- 90 degree, still horizontal

- 90 degree to vertical (going up)

- T - to primary loop return. (there's a grundfoss pump inside my triangle tube for the primary loop which can be set to low/med/high, and it was set to low)

- T to primary look supply (T's are actually touching eachother, very little mixing area)

- 90 to horizontal

- 90 - still horizontal

- ball valve with flange to connect to taco circulator

- taco circulator

- ball valve on flange to taco

- brazed in 1/2" cold water supply (from top of this horizontal pipe)

- 90 to vertical (which was leaking on the vertical side and I heated and added flux and solder to fill the tiny hole)

- Big 2" cast 90 with a small 1/2" pipe in it, switches to horizontal.



Some info:

- I drained the boiler to do 4 things:

(1) connect radator where one was removed and the two pipes were plugged.

(2) remove long rusted kitchen baseboard radiator for kitchen renovatsions

(3) remove third floor bathroom radiator for bathroom renovations

(4) fix the leak in the supply pipe copper (did not disconnect, just heated and addded flux and silver solder, can't imagine I clogged the 90.)

- The pipe on the outlet side of the Taco never gets warm. 

- Pipes between the Supervent and the taco pump are hot, boiler stops combustion when water reaches ~105 F, but temp rises to almost 120 some times when it fires because it is heating such a small amount of water.

- The taco almost always seemed loud and ran hot from day one.  It sounds quiet when running, but I can hear it running.

- I had high velocity central air installed this spring, and the unit was wired to the same thermostat, and it seems to be wired correctly as the pumps seem to turn on when they are supposed to.

- I did vent all the radiators from bottom to top, and vent the boiler, but I do hear gurgling in the boiler, more-so when I switch the internal pump speed to med or high.

- I did have the outlet side of the taco pump disconnected to completely drain the leaking copper fitting.  I reconnected it and figure my next step is to see if there is some obstruction at the pump. 

- I don't know how to check if there is an obstruction in the super vent because the installer did not put a valve in between the supervent an the rest of the system return.  So the whole system would need to be drained again. 



Any ideas?  Would a picture help? 



Could it be as simple as nothing wanting to flow because I took out two radiators off?  I thought all the radiators were connected in parallel and this would not cause such a problem.