Purging 1 zone, in a complicated system, please help

[Overmyhead]

The #2 zone in my 4 zone system isn't heating up. When I crank to thermostat up it turns on the taco pump. But the baseboard heater doesn't heat up. I figure it's airbound so I was going to drain that zone but I'm not 100 % sure how to do it and I have a tendency to bite off more than I can chew. I haven't found anything on YouTube that is identical to my system, most are simpler than mine so I'm hoping to get some advice before I start trying to drain the zone.

Here are some pictures of my system and how I think it works:

Picture 1 I think that water runs from the street straight into the boiler
Picture 2 hot water travels up to the expansion tank
Picture 3 then travels from the water tank to the line up of zones.
Picture 4 This picture may be better than #3 the water flows from the expansion tank passing through a flo-control valve into the zone above and back to a taco pump that pushes the water back into the boiler.

Here is my plan to try to drain the nonfunctional zone:

1. Turn the power off to the boiler.

2. Picture 3 : I plan on leaving open the ball valve in zone 2 and closing ALL the other ball valves below the flo-control valves in picture 3.

3. Picture 4: I plan on hooking up a hose on zone 2, to the drain spigot that is above the ball valve in picture 4. I plan on closing the same ball valve and turning on spigot that the hose is connected to in zone 2 in picture 4. This should hopefully drain zone 2 into a bunch of empty buckets.

4. Picture 1: I plan on using the pressure control valve that is before the boiler to push the air bubbles out of the zone and fill the zone up with fresh water.

I'm afraid of a bunch of things going wrong, like will the expansion tank cause problems with this plan, will the street pressure blow something out, is there an easier way to do this?

 

[Overmyhead]

Sorry having trouble uploading pics

 

[Overmyhead]

Picture 3 of 4

 

[Matt30]

The zone in question has an automatic air vent. Is it functional?

I suspect more of a circulator issue then air.

If it is air locked, you don't need youtube. That's a simple system. Isolate the zone in which you want to purge using the valves provided, then close the valve under the drain valve on the zone you want to purge, open it and keep the pressure up on the boiler. Don't completely drain the zone, defeating the purpose. You're just introducing air. Get water moving, then you're done. If that doesn't work, start looking at the circulator. Just because it's powered doesn't mean it's working

 

[Overmyhead]

Second of 4 pictures

 

[Overmyhead]

Matt, is that the bike tire air nozzle looking thing?

 

[Matt30]

The small brass cylinder on top of the return piping, yes. It could be stuck...unscrew the cap and push on the centre like a bike tire.,it's not the exact same as a bike tire but same idea.

Those caps aren't meant to be tightened down either. Just on there loose so air can escape.

 

[Overmyhead]

I just purged the zone and it worked like a charm. The heat is cranking in the kids bedrooms. I owe you a beer matt30!

 

[Matt30]

Glad you got it going. Good job!

Next time you're trying to figure out your system, just simplify it. You're making water go in circles. Trace out your piping and use what valves are there for you. It will make things much easier next time around