Heating, Air Conditioning, Fridge, HVAC/Air Bubbles


Hi Craig,

I have a 1400 square foot brick ranch home insulated fairly well. There is a cold start New Yorker FR hot water furnace installed in 2010 in the basement. The radiators are the fin type closed system.

Two weeks ago the Auto Vent valve started leaking. This vent is on top of the expansion tank on the side of the furnace in which the main water line runs to the three zones. The owner of the company who installed my furnace told me to tighten the cap on top of the valve as tight as I could with my fingers. That worked for a few days.

When I came home from work a couple of days later, water was leaking down onto the furnace and onto the floor. I put a bucket on the furnace and floor to catch the water. They sent a man out the next morning. I left my basement door unlocked so he could do the repair.

He replaced the vent and said he put the system back into operation that morning. When I came home the Taco circulator that is connected to the hot water tank was making a loud noise. The same repair guy came back out that night.

I asked if there was air in the line stopping the flow of water making the circulator run non-stop. He said maybe. He bled that zone and asked me to turn up the thermostats on the three heating zones so he could purge the zones. Turns out that when he tried to purge the air earlier in the day, he was tripping the circulators to get them to run to drain the air out of the lines since he did not have access to the upstairs to turn up the thermostats. He spent 90 minutes labor to change that vent and get the air out of the system. That seemed like a lot of timefor draining down the furnace enough to replace the auto vent valve, refill the furnace, and bleed the lines. Do you agree?

He bled the three zones again that evening but was only there I'm guessing about half an hour.

Craig, now my house seems "cool" even when the room's thermostat is set to 70 degrees where I always keep the setting. Seems like in the past the house was always warmer before he replaced the vent valve and bled the system. How possible is it for the furnace to heat the house but have the house still be cool?

I am wondering if maybe the amount of circulation through the zones is decreased when the circulators are not running after he tried to remove air from the zones?

Thank you for your help Craig,



I am not one to guess how long it takes to do something as a general rule.  I might say something it the time seems really absurd.  

It is possible you have air in your system.  The air could be caught up in the zone heaters.  Air in the zone heater coils will reduce the heating capacity.  There should be air vents on each one. The small circulator pump(s) may not get the air back down to the air separator.  


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Craig HVAC Expert


I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.


I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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