The fact that this video only has 1.7k views and yet countless videos on troubleshooting air and pressure related issues in modern hydronic heating systems have hundreds of thousands, speaks volumes about the state of the residential heating industry. I recently began residential service work, with my prior experience being big commercial hydronic systems and the amount of failed expansion tanks, popped relief valves, leaking auto vents, air bound systems, etc.... that have all just been excepted as facts of life with hydronic heating systems was alarming, The very first thing I noticed was nearly every single one of these systems had circulators on the return pumping into an expansion tank. Anyone that understands any basic hydronic or fluid dynamic principles can understand immediately what causes these issues. The negative pressures on the circulator inlet allow the system fill to continously add makeup water to the system, autovents draw constant air in, expansion tanks get filled with water until the bladders fail, then excess pressure exits the system through the relief valves or autovents. The effect of constantly adding undissolved oxygen into the system compounds all of these issues and creates endless issues and component wear. This video should be part of a required curriculum for any hydronic heating installer or servicemen. We need technicians that understand the theory of how these systems operate, not parts changers and salesmen of misinformation.
The first book I read the hydronic analysis looking to learn about hydronic testing and balancing. It was so great I couldn’t even understand at the time. This is someone I was so proud to learn from. My teacher Tom also loved his book. 🙏 gave me so much confidence.
Very nice demonstration. But... what would be the point of no pressure change if there is no expansion tank in the circuit (theoritically suppose a closed loop circuit which has no heating/cooling function)?
In your theoretically static temperature closed loop example with no expansion tank there wouldn't be one and it would not matter where the pump is located.
