Boiler not filling with water after purge

[Ocelot]

I have a boiler with 3 zones. 1 off the TACO and then 2 more that are split in their own zones. I purged the 2nd floor zone as the pipes were rattling like mad and there are no bleeder valves that I can find on the baseboard radiators.
1 zone is supposed to be 1st and 2nd floor of the original house. Zone 2, 1st floor addition, zone 3, 2nd floor addition.

At first it didn't seem like their was water coming back into the system. Now I can't tell. I have heat throughout the house and can hear water gurgling.

I tried to bleed the radiators in the old part of the house and water comes out on the first floor, but just air on the second. I am starting to wonder if they aren't fully closed loops, maybe the returns aren't zoned?

My worry is that the pressure gauge shows no pressure, but I have heat. Is there a way to tell if there is water and manually add if necessary? Don't have the $$ to get someone out to check the water for a few weeks.

Thank you!

 

[Reach4]

My worry is that the pressure gauge shows no pressure, but I have heat. Is there a way to tell if there is water and manually add if necessary?

Sounds like a bad pressure gauge. However I have no idea what your pressure gauge is supposed to be measuring or what the right number would be.

 

[Sponsor]

 

[Dana]

If air is actually coming out on the second floor rads when the pump isn't running it means the system is pressurized, and if you add more water it'll eventually start putting out water. The pump may be able to push water to the top when running, getting enough flow to get heat, but the top of the system really needs to be under positive pressure even without the pump running.

At typical 2-story + basement with the boiler in the basement needs about 15 psi, measured at boiler elevation to fill the system all the way to the top, with enough additional pressure to prevent pump cavitation when the pump is running.

A cheap water pressure gauge with a hose thread fitting is good enough to ball-park it, even though they are usually only marked in 5 psi increments.

 

[NYC-Plumber]

Hello.
First and foremost the boiler has to be in the off position for any bleeding and or purging of system. Secondly, if it’s a baseboard system that you have such as slant fin and or embassy you don’t need air/bleeding valves on the baseboard as it is nothing more then just the continuation of the supply/return of piping from and to boiler. Looking at the pictures, I see that you have circulating pumps on the return and zone valves on the supply. Make sure that the zone valve of the zone you are trying to bleed/purge is in the open position which you can manually do so by moving the lever of the zone valve located under its box and make sure that you position that lever in the semi vissiable hook which you have to pull all the way to right then slightly forward so that it hooks onto it. Connect a garden hose to the hose valve of that zone onto the return end of it and turn of the ball valve under it. Turn on the water and begin bleeding process. If you don’t hear any sound of air and or water going through make sure you are connected to the correct return hose valve. Once you have the correct return then let water run for about 10 -15 min. Until you no longer hear gurgling in the line. However, based on pictures, there are other parts and components missing on boiler that could and would make a better system.
I hope it helps

 

[Dana]

Unless there is a check valve in series with the pump or the zone plumbing, bleeders at the top of the system will still allow it to be filled without opening the zone valves, But that is a good point. Many Taco pumps have integral check valves that can be either installed or not, and it wouldn't be visible in the pictures.