Last week we did a video on zoning for residential homes and this week I wanted to touch on a little bit more on the technical side of the zoning setup That's coming up on Fox Family Heating and Air Conditioning Hey, if this is your first time watching our channel Please click subscribe down here on the bottom right and if you clicked that little bell next to it You'll be notified of all of our videos as they come out some HVAC installers say you can't truly set up a unitary Drafted HVAC system like the ones that the majority of us in the United States have set up in our homes Remember zoning is for homes that have two thermostats one for upstairs and one for downstairs They typically allow for one HVAC system to heat or cool one zone or the other But definitely not the whole house at one time If you're an HVAC technician, let me know in the comments down below How you like to set up bypasses and dump zones to get rid of the extra air that zoning creates I'm sure it's a little different all around the world and I'd love to hear about it Train and carrier have some really nice setups when it comes to their variable speed systems and Modulating dampers that open and close strategically allowing you to really dial in the rooms that you want a condition and win But buying one of those systems is no joke Currently, I'd say only about 7% of the market are actually buying this high-end equipment They really are advanced technology compared to the traditional zoning equipment Americans are used to in their homes today But I'm sure this technology will be mainstream soon enough Traditional zoning uses two thermostats those thermostats can be smart Wi-Fi thermostats or standard digital programmable thermostats And those two stats talk to a main zone board at the furnace or air handler That main zone board then tells the air handler when to come on either in air conditioning or in heating mode as well as which floor to have come on Zone systems are purposely designed to be about a half a ton larger than the largest zone in the house Last week's example of a home with two floors one at 1150 square feet and one at 800 square feet Would be sized at two and a half to three tons depending on the insulation levels and other load characteristics That large of a system is capable of producing a thousand to twelve hundred CFMs The smaller 800 square foot zone cools the bedrooms and bathrooms upstairs as well as the laundry room But a thousand to twelve hundred CFMs is way too big for 800 square feet So what do we do with the extra air? We bleed it off to another area of the house Now we have a few choices as where to disperse that extra air We can create a barometric bypass back to the return plenum or return grill We can create a bypass dump zone in another portion of the house Or my favorite bypass the air to the other zone through dampers that are set up properly for this Option one a barometric bypass straight back to the return plenum In my opinion This is the worst way to get rid of the extra air because it sends it immediately back to the return Through an 8 to 10 inch duct with a barometric damper that cracks open with the extra air pushing against it The more extra air there is the more the damper opens allowing air back to the return plenum This super heats the return air in heating mode and super cools the return air in cooling mode How does that affect the system? In the heating mode if we have 65 degree air initially entering the return side of the furnace or air handler It goes through the furnace and gets heated up about 40 degrees to a supply air temperature of about 105 degrees Where that air exits the registers in each room If one zone is open and the other is closed the extra air gets sent through the 8 to 12 inch duct Immediately back to the return plenum and mixes with that 65 degree air Essentially raising the return air to about 70 to 75 degrees in that return air plenum This air then gets heated up to 115 degrees which now heats up the return air in the plenum to 80 to 90 degrees On and on this goes until the system has super heated the return air so high that the limit switch turns off the burners because the supply air is too hot And that's pretty hot because those high limits are usually shut the burners off at 165 to 200 degrees What does that mean the return air got to? 125 to 160 degrees. I see it all the time The same thing happens to the evaporator coil when the cool supply air gets sent back to the return plenum And recycles over and over until that air gets so cold that the evaporator coil eventually freezes and blocks the airflow Which causes even more problems Option number two a dump zone In this scenario we send the extra air through a duct about 8 to 12 inches To a dump zone or another section of the house I've worked on crews that chose to dump the air into the living room and then others that dumped it into the foyer with a 25 foot ceiling I'll admit that was pretty scary installing that one Trusting those ceiling joists to hold me up as I was cutting in that 20 by 20 can was a little intimidating I wasn't the lead installer on those jobs In fact, I was just a helper at the time But what we learned from those jobs was the air being dumped into that living area Was making the rooms uncomfortably warm or cold depending on the season Having learned our lesson we started dumping that air into the end of the return duct To either a why where the duct meets the can or a collar cut into the return can itself at the ceiling I like cutting it into the can because the colder hot air gets to mix a little bit more with the return air Before being drawn through the furnace or evaporator coil again This way the super heating or super cooling doesn't happen as fast or as easily An option three bleed off to the other zone through the dampers The option that we take at Fox family is to bleed off the air to the other zone through a small gap left as the damper closes See we don't let zone one or zone two damper close all the way and there are settings on the honeywell AR dampers that meter the correct amount that the installer decides Referring back to the house that has the 1150 square foot and 800 square foot zones If the smaller zone is calling for cooling the other 400 CFM's of air is redirected to the bigger zone This way it won't be dumped into one single room But be distributed evenly through the larger zone through several registers Great thing is this air won't over cool or overheat that unused zone And at the same time allows the system's static pressure to be regulated at a closer level to manufacture specs Which will extend the life of the system Duff the systems are becoming more and more popular in America They're great for zoning individual rooms one at a time But for those of us who already have supply registers and ducks leading to every room in the house Zoning is still a complicated issue Taking care of the HVAC system is a main priority for an HVAC installer And there are some folks who will just hack it in and others who try to do it right As always I would love to hear your strategies and comments about how you incorporate zoning into a house All of us are a little different because we work in different parts of the world So let me hear about it down below in the comments section And if this is your first time watching our channel please click subscribe down on the bottom right And if you click the little bell next to it you'll be notified of all the videos as they come out Thanks so much for watching and we'll see you on the next video You're watching Fox Family Heating Air and Solar Don't forget to subscribe And check out more of our videos by clicking on the right side of the screen You