Lo heat on one zone

Matt_14

My home is equipped with a hydronic system that is divided into three zones: Garage, 1st floor, and 2nd floor. The 2nd floor delivers heat thru baseboards. Copper tubing imbedded in concrete slab delivers to the other two zones. There are no vents on the baseboards, and, as far as I can tell, a Taco 400 Hy-Vent, installed about seven feet above garage floor level, on the return line elbow is the only means of eliminating air. Just recently, about a day or so after a new expansion tank was installed, the baseboards on the 2nd floor were not heating up (temp at thermostat showing about 60-62 degrees, set at 68 degrees) though the other two zones are working just fine. When placing my hand near/on the baseboard, it's obvious that they are not heating up enough. The temperature outside has been hovering around 20 degrees.

The contractor who installed the expansion tank is not available until the following week, so a second contractor was summoned. He spent about two hours trying to purge the system of air, with little success. Suggested that a purge valve be installed on return side, below the Hyvent, to elimate trapped air. I have lived in my current home for just over 3 years and have noticed gurgling and bubbling when the 2nd floor heat zone kicks on, and once or twice, noticed that the heat on the second floor was not producing. After removing the Hy-Vent and cleaning it, the system ran just fine (the Hy-Vent should be only about three years old). The contractor who was purging, stated that the vent is poorly placed, and will introduce air when removed. What is the proper way to clean this valve, and should the small screw cap at the top be closed finger tight?

Also, the heat has been running continuously since the 2nd contractor left, though I shut off the thermostats!?! Shutting off the power seems to be the only way to stop the system from running. What do I need to get it back on thermostat control?

lchmb

ok, I think from what your saying there is no purge station on the return side of the 2nd floor zone. If this is the case then the hy-vent is the only way to remove the air for now. I would go with his suggestion to add a purge station to get the system purged properly. I would replace not repair the hy-vent. shut off the feed into the system and replace it. Once done, turn your auto feeder back on, you should start to hear air escape from the hy-vent once the zone is open (zone valves or circulators? As to a hy-vent on a return side, I personally do not like them. I have seen many pull air back into them when piped this way. Once you get a purge station set up simply close the hy-vent. As to the zone not shutting down, I would wonder if the tech jumped out the thermostat. Did you watch him? If so did he jump a zone out trying to purge it or if you have zone valve's check the little handle to make sure it's not in the manual position...Hope this helps some!!