Lack of heat in one loop

nahm

The house has a four zone Hydronic baseboard heating system. The non-heating loop is in the zone for the second floor. The zone is divided into two loops in the basement and each loop has a separate return to the basement. There are no air vents on the second floor and each loop has a separate Purge and Balancing Valve ( see picture). The pipe supplying the non-heating loop is cold at the point the two loops divide.

I suspect that there is an air pocket in the non-heating loop but with no air vent and the purge valve not getting the air out i was wondering it i could use a self-tapping saddle valve to drain the air until i can turn off the heating system in the spring?

Gordy

Did you isolate first floor while purging second floor? Or is isolation not possible.

System pressure what is it?

icesailor

DO NOT INSTALL ANY SADDLE VALVES!!! It will be a waste of time.

On those fittings with the boiler drains on them, the gray lever part is supposed to stop the flow from the return from the boiler. You do NOT need any air vents on the baseboards. Unless someone convinces you that you need them. I never did. You may have to post a photo of the boiler, and if it is a long ways away, you might need help. But the two purge valves you have marked for the second floor, you must close them both. In fact, I would close them all. Put a hose on the zone that isn't heating. raise the system pressure to over 20# and make it stay there while you purge. Closing the purge valves means that you move the gray handles perpendicular to the pipe. Drain the purge water into a 5 gallon bucket. Once you open the boiler drain, you might feel the pipe start to rattle and shake. That's the air. If the hose is in the bucket, when the air comes, the hose might blow water all over the place when the end jumps out of the bucket. You will feel the water start to get hot. Wait a minute because the water might cool for a moment then get hot. Shut of the hose drain and open the gray lever part of the valve.

That type of purge valve is sort of useless at times. It doesn't have a positive shut off and it can suck water from the other returns on the zones.

Those Flair purger's were added later. Post a photo of the boiler, especially the return. There is another way to purge it. Whomever did the original installation probably had a way in mind to purge it. The next person couldn't figure out how to do it so they added those bogus purge valves. Watts makes a good one. Califfi might make a good one too.

nahm

pressure is about 20 psi
tried purging at the purge valves and a drain valve on the return line.

icesailor

All I can say is "What were they thinking?".

When they connected that new Peerless WB to that indirect, they increased their problems tenfold.

That's when they installed the Flair low budget purge valves. Because they couldn't get the air out.

And with the PRV/Fill Valve that high up on the return with no ball valve to shut it off or make it go through the boiler first, Mother nature gets very angry when you try to fool her.

You or someone needs to put a copper ball valve in the return ABOVE the fill valve. If you put a boiler drain in above the valve, you don't need to purge through those Flair purge valves. You do it with the zone valves.

OBTW, you DID have the zone you wanted to purge open at the zone valve with the thermostat calling. All the others can be off. But the cold return is always going to try to get past the butterfly gate in that purge valve.

You can go into most any P&H shop that has been around awhile. Look in their boxes where they have saved stuff for future use. It never gets used. You will always find a few of those Flair butterfly purge valves. They're probably left over from something way back in the 1980's.

IMO