Elk M1G and HVAC Zone Controllers

[DotNetDog]

I am building a new house and I'm thinking about going with 4 HVAC zones upstairs (one zone per bedroom). I will be using the Elk M1G for security and most automation. So I tried to research this topic but I haven't seen much latetly, within the past year.

I like the Aprilaire 6504 controller. I just started looking at the RCS zone controller. My question is whether I ned to go with communication thermostats and have the M1G talk to the thermostats rather than the zone controller. It looks like that was the plan a fews ago but has Elk improved this capability so that I can go with non-communicating thermostats?

Any thoughts/help/advice would be appreciated. Thanks!

 

[DotNetDog]

No one?

 

[robolo]

There are 2 separate issues with zone controlled HVAC. The first has to do with individual zone's settings such as set point for temp, heat or AC mode settings, on/off as well as the actual temp reading of that zone. The second issue has to do with the "smarts" of taking the individual zone settings and deciding which dampers need to be opened or closed, whether to turn the blower on/off, turning on the furnace etc.

You can use communicating thermostats without a separate controller and use the ELK as the controller but it requires a lot of work. Although a few folks have written ELK rules to do the smarts part it is probably a lot easier to have a controller do this as you are planning. Also you can't just mix and match controllers and thermostats. They have to be compatible models from the same company.

The Aprilaire 6504, I do not think, is able to communicate with home automation systems. There is no output for this on that unit. It is also only designed to work with the Aprilaire 3020A thermostat which is non communicating.

As for the RCS, which is what I selected, the ZCV series control units have RS485 serial communications ports. It
can send and receive data and commands by serial communications to allow remote control of the
system. Commands including requesting status of zone temperature, setpoint, heating/cooling mode and
fan mode as well as setting any zone setpoint or mode. Individual and global zone commands are
allowed. There are only a couple of RCS thermostats that are compatible with the ZCV controllers. RCS Wall Display Units that are RCSLink2 products, such as Model TS16 and TS40 can be used with ZCV series controllers.

Hope this helps
Robolo

 

[JeffVolp]

There are issues with a multi-zone HVAC system that have to be considered to prevent damage to the system. That is why I opted for a dedicated multi-zone HVAC controller myself (Carrier/Bryant). It is expensive, but has worked flawlessly for the last 7 years.

The main issue is proper control of the exhaust temperature. Here we have 8 zones and dual A/C & furnaces configured as a two-stage system driving common ductwork. For most of the year just one unit carries the load. The second unit kicks on under heavy loads. Examples would be quickly warming up the "daytime" regions of the house on a cold winter morning, or when it is over 90 degrees outside.

Since we have 8 zones, if only one of the smaller zones kicks on, there would not be enough airflow if just that one zone is open. In the winter the furnace would overheat, or the evaporator would freeze in the summer. The zone controller monitors the duct temperature, and cracks open other zones so that sufficient airflow is maintained. It decides what to open based on how close the zones are to their desired temperature. Unoccupied zones are also used to dump excess airflow if necessary.

While it is certainly possible to program this in an automation controller, it seemed like more work that I wanted to do myself.

Jeff

 

[gacevich]

i use aprilaire, elk and cqc to control my hvac system.

 

[Tdar]

There are issues with a multi-zone HVAC system that have to be considered to prevent damage to the system. That is why I opted for a dedicated multi-zone HVAC controller myself (Carrier/Bryant). It is expensive, but has worked flawlessly for the last 7 years.

The main issue is proper control of the exhaust temperature. Here we have 8 zones and dual A/C & furnaces configured as a two-stage system driving common ductwork. For most of the year just one unit carries the load. The second unit kicks on under heavy loads. Examples would be quickly warming up the "daytime" regions of the house on a cold winter morning, or when it is over 90 degrees outside.

Since we have 8 zones, if only one of the smaller zones kicks on, there would not be enough airflow if just that one zone is open. In the winter the furnace would overheat, or the evaporator would freeze in the summer. The zone controller monitors the duct temperature, and cracks open other zones so that sufficient airflow is maintained. It decides what to open based on how close the zones are to their desired temperature. Unoccupied zones are also used to dump excess airflow if necessary.

While it is certainly possible to program this in an automation controller, it seemed like more work that I wanted to do myself.

Jeff

I would agree with everything that Jeff said I'll just add that Elk has support for the Carrier/Bryant system in the M1G. So you can have your Elk and a well designed multi zone system at the same time.

 

[fcwilt]

Also you can't just mix and match controllers and thermostats. They have to be compatible models from the same company.

Not always the case. The zone controller for my Lennox system uses plain old single stage dumb thermostats. I was able to replace these with RCS-TR40s without any issues but you could use HAI or Aprilaire or any other communicating thermostat that can be configured for single stage heat/cool.

The thermostat requirements for the specific zone controller you are considering are what you need to investigate.

 

[DotNetDog]

Thanks for all the replies. I have to admin...I'm still confused. Is it better to go with a non-communicating zone controller (like the RCS ZC series) and use communicating thermostats? That configuration seems like it would be easy for the Elk M1G to automate since it would simply appear as a normal HVAC system with multiple thermostats.