No heat - How to get air out of hydronic baseboard system

Steve Garson_2

My heating contractor added a loop for an addition yesterday, but he did not properly evacuate air in the system, so I don't have heat in a few of the loops. He went out of town for the weekend so I am forced to do this myself.

He told me to simply:
a. attach a hose to the sill cock, which is on the return manifold
b. close the valves for all but one zone to be bled
c. open the sill cock valve
d. let water run until the air valve stops hissing
e. then close the zone valve and open the next one.

The zones don't hiss any more, but I have only one zone working, though a Runtal radiator on that zone continues to sound turbulent even though the bleeder valve on the Runtal emits no more air. But some of the zones still do not work. Should the boiler be cool when this is done, since cold water is entering the system?

My question is:
a. Should the ball valve at that closes the return to the boiler be closed when I do this?
b. Should the ball valve that mixes the feed and the return be open or closed when I do this?

I'm frustrated that I have to do this myself. I'm amazed that there are no bleeder valves on the baseboard radiators. This is a two story home with boiler in the basement. I have the water pressure set to 15 psi. The system has an air scoop with vent, as well as a vent on the boiler side. WM SG-4 boiler.

Any advice would be appreciated!

Steve in Denver, CO

Intplm.

You are on the right track.
Turn the power to the boiler off.
Yes close the bypass valve.
When you say "Let the water run until the air valve stops hissing" not really.
Do this instead.
Take the other end of your hose and secure it at the bottom of a large bucket/five gallon pale out doors. Now you can start your purge.
Let the water run for awhile as you observe air bubbles bubbling up from the bottom of the filling bucket. When you no longer see bubbles, you have purged that zone. Be patient. Watch the water and bubbles flow.
You might also need to purge other zones too as they may have lost water during the addition.

Steve Garson_2

Should I leave the valve to the return open? How much time is considered "being patient" per zone?

Intplm.

Steve Garson_2 said:

Should I leave the valve to the return open? How much time is considered "being patient" per zone?

Can't see from your pic. But , if the return valve is closer to the boiler than the purge valve, or the purge valve is above the shut off valve on the return then close the shut off valve on the return. This way the water will stop at the return shut off valve and air and water will purge from what you called the sill cock valve. ( it's actually called a boiler drain. )
Patiently wait for the water and air to flow till you no longer see bubbles bubble up from the end of the hose that is in the bucket. The time it takes is dependent on how long the zones piping is. Some will take longer than others. Just stay outside and watch. And once you are no longer seeing bubbles stay and watch a bit longer, maybe as much as five minutes per zone. You will know best as you continue the purge.
Once you are done with one zone, move on to the next and so on till you do not see any bubbles from each zone.
Any minute residual air should purge out from the air purger installed on your boiler.

Intplm.

@Steve Garson_2
Please post your results when you've finished

Just now was able to see the valves. The bypass and the valve installed on the return.

Yes. Close both of them.

Steve Garson_2

Thanks! Will try that now!

Steve Garson_2

Intplm, many thanks for your assistance. My system works as it should now. My guess is the contractor who did the work doesn't do much hydronic, even though he said he does. Your recommendations were spot on! Thanks again!

Intplm.

Steve Garson_2 said:

Intplm, many thanks for your assistance. My system works as it should now. My guess is the contractor who did the work doesn't do much hydronic, even though he said he does. Your recommendations were spot on! Thanks again!

Happy to help. Glad it worked out.