We have a First Co. hydronic HVAC system that was installed in 2016. In the air handler unit, the evaporator coil is at the bottom, with the blower and heating coils above it. There's a loop for the space heating with the return flowing back into the hot water tank, and a mixing valve for the water supplied to all the taps. During the cooling season the HVAC technicians advise turning off the space heating supply and return valves, either above the air handler or at the hot water tank. The pump normally runs every 6 hours, even with the system off; we've read that is to prevent bacterial growth. We keep the 75-gal Bradford White Hydrojet tank temp at 135-140F. We haven't checked the chlorine content, but at times we notice a strong chlorine odor.
1. If we leave the heating supply valves closed for 5-6 mos (in VA) could Legionella grow in the stagnant water in the pipes?
2. If we leave the heating supply valves closed, could an air gap develop requiring flushing of the system when heat is turned on?
3. Would stagnant water in the heating coils increase the likelihood of coil corrosion?
4. If we leave the heating supply valves open, and let the pump run every 6 hours for one minute, would the 50-60 degree cooled air passing over the warm coils (max 140 degrees) above the evaporator coil cause enough condensation on the heating coils to cause a problem?
Thanks for sharing your thoughts/advice!
1. If we leave the heating supply valves closed for 5-6 mos (in VA) could Legionella grow in the stagnant water in the pipes?
2. If we leave the heating supply valves closed, could an air gap develop requiring flushing of the system when heat is turned on?
3. Would stagnant water in the heating coils increase the likelihood of coil corrosion?
4. If we leave the heating supply valves open, and let the pump run every 6 hours for one minute, would the 50-60 degree cooled air passing over the warm coils (max 140 degrees) above the evaporator coil cause enough condensation on the heating coils to cause a problem?
Thanks for sharing your thoughts/advice!