I am thinking about setting up a zoned HVAC system. I have an Elk M1G, and I think I will use that as the brains of the system. I have done some searching here, but it's kinda hard because "zone" comes up in a lot of other non-hvac posts. I have been around on the internet elsewhere, but I still haven't found a good basic tutorial on getting started with retrofitting such a system. Can someone please point me in the right direction (even a library book would be fine)? I have read every word at http://diy-zoning.sourceforge.net/, and the things that turn me off about his system is that 1) it requires yet another 24/7 PC (most likely linux) and 2) there are no local thermostats--all the control is in the PC. My requirements are 1) local thermostats in each zone (these do not need any type of remote control); 2) the usual safety to ensure enough airflow over the coils/condenser, which usually means no more than X number of zones closed at a time; 3) flexible to some day add humidity control
Zoned HVAC
- Thread starter MrGibbage
- Start date
sda
Active Member
You should gather some information about your current HVAC system before you do anything. Stuff like how many CFM its moving, static pressures, and a map of the existing ductwork.
Is your current HVAC system even working correctly? How do you know that ? Oh, some service guy that didn't graduate from high school told you so? Remember the Dateline NBC expose (that's ex-po-zay) where they were sucking refrigerant out of a properly charged system? Learn about your HVAC unit and check what you can. At the very least learn where your indoor coil is and clean it. Check your ducts, seal any leaks, insulate if appropriate.
You might even want to have somebody reliable run Manual D's and Manual J's on your house to see how its performing now to give you a staring point. I think there's some fairly cheap software you can buy to do them yourself. That's another thing that ticks me off about HVAC; the Manuals which contain the formulas for the calculations are not public domain. They are developed and sold by ACCA yet the building authorities require the calcuations. That's a self serving closed loop society.
I checked out the sourceforge link. Didn't read the whole thing yet, but it looks like they cover a lot of theory and how to in the FAQs. DZ (the software) is written in Java. Personally I hate Java but that's another topic. Download the source and figure out how it works. You'll just need to apply it to your own situation. Its not a one size fits all.
For a conventional looking approach, what I would try is a non programmable digital (for accuracy) thermostat in each zone. Supply 24vac to each thermostat. When a call for heat/cool occurs, have it close a 24vac coil relay whose contacts can then be sensed by the contoller. I'd have the 24vac xformer and relays near the controller and home run regular thermostat wire to each one. You'll need to use two (or three to detect fan) inputs for each thermostat.
Is your current HVAC system even working correctly? How do you know that ? Oh, some service guy that didn't graduate from high school told you so? Remember the Dateline NBC expose (that's ex-po-zay) where they were sucking refrigerant out of a properly charged system? Learn about your HVAC unit and check what you can. At the very least learn where your indoor coil is and clean it. Check your ducts, seal any leaks, insulate if appropriate.
You might even want to have somebody reliable run Manual D's and Manual J's on your house to see how its performing now to give you a staring point. I think there's some fairly cheap software you can buy to do them yourself. That's another thing that ticks me off about HVAC; the Manuals which contain the formulas for the calculations are not public domain. They are developed and sold by ACCA yet the building authorities require the calcuations. That's a self serving closed loop society.
I checked out the sourceforge link. Didn't read the whole thing yet, but it looks like they cover a lot of theory and how to in the FAQs. DZ (the software) is written in Java. Personally I hate Java but that's another topic. Download the source and figure out how it works. You'll just need to apply it to your own situation. Its not a one size fits all.
I couldn't find that specifically, but I'll take your word for it.
For a conventional looking approach, what I would try is a non programmable digital (for accuracy) thermostat in each zone. Supply 24vac to each thermostat. When a call for heat/cool occurs, have it close a 24vac coil relay whose contacts can then be sensed by the contoller. I'd have the 24vac xformer and relays near the controller and home run regular thermostat wire to each one. You'll need to use two (or three to detect fan) inputs for each thermostat.
Black Magic
Member
I wrote some code for the Elk system that makes it work like an HVAC zone controller. My HVAC has been controlled by this code since before I made this post. I may have modified it a bit since then (I can't remember).
http://www.cocoontech.com/index.php?showtopic=7149&hl=
http://www.cocoontech.com/index.php?showtopic=7149&hl=
