Was just thinking and trying to plan out what I need to implement the ELK M1 in my home. In the area of temperature control, I have a hydronic warm air system with A/C - 2 air handlers, one which has 2 zone dampers.
In looking at thermostats (HAI models), I then questioned if I even need them - and might be better suited to simply using temperature sensors in the place of the 3 themostats. Am I missing something or does this make sense?
I know that some T-stat models can hook up to the zone damper (ZD)control as well, but also think I could interface to ZD control from the M1 panel -or- use the relay interface and control them without a ZD controller.
In my world of justifying toys and gadets, me thinks if I can save some money be eliminating 3 fancy communicating thermostats, I can justify the $1200 (ouch!) touch screen with less sharp pain.
The main reason to use thermostats is as a demarcation and user interface to the HVAC system.
In your own home this might not be needed. If you are comfortable with servicing your own HVAC system the demarcation between HVAC and automation isn't an issue. However if you have problems with the HVAC system be ready for whatever brain dead tech that comes along to blame any problems on your automation system and try to sell you a whole new HVAC system.
Thermostats present a fairly friendly user interface that most people can understand. You may be able to make a better interface with a touchscreen (especially for a 3 zone system) but not everyone will look for temperature controls in a non-thermostat type device. Once again, in your own home this might not be a problem unless you regularly have house sitters, guests or others that might need to adjust the temperature.
One other item is that thermostats have a anticipation feature that will start the unit before a set point to make the temperature more even. You should be able to code a feature like this.
I have a similar issue in my house. Since it is a older house with 2 floors, a single HVAC unit and no return air from the second floor a thermostat does not work effectively in the summer. I solved this problem by using a Homevision to run the AC according to duty cycle instead of temperature. My control relays run in parallel with the existing thermostat and I set the duty cycle to 0 minutes per hour when the HVAC guy comes. I pick up the current HVAC status via debounced LEDs across the existing thermostat contacts. This way the Homevision knows when the thermostat last ran the AC and won't short cycle of run the AC prematurely.
Since I have gone over to a M1 I am now debating myself whether to get an controllable thermostat (RCS) or migrate the programing over to the M1.
I'm planning to integrate my HVAC system (2 air handlers, 1 zone each) with the ELK-M1G. The plan is to switch to communicating thermostats but with a twist. I will allow anyone to change the settings of the stats but every 10 or 15 minutes the system will reset the stats to my programmed choices for day/time and system status. This will allow my wife and her sister to do whatever they want but only for a few minutes. Thus I have solved the perennial problem of marriage between a New Englander and a girl from the topics. :^)
Great response.. Thanks. I did think of HVAC service, that is pretty much limited to the boiler but is key as you mention. Was thinking of some simple override switching, but at that point might as well just put in the thermostats.
In article , email@example.com (Robert L Bass) writes: | "Bill Kearney" wrote: | >
| > I'm likewise mulling over just how to integrate a thermostat into a | > larger HA setup. | | I'm planning to integrate my HVAC system (2 air handlers, 1 zone | each) with the ELK-M1G. The plan is to switch to communicating | thermostats but with a twist. I will allow anyone to change the | settings of the stats but every 10 or 15 minutes the system will | reset the stats to my programmed choices for day/time and system | status. This will allow my wife and her sister to do whatever they | want but only for a few minutes.
Rather than that you might want to have the thermostats tell you when someone makes a change (Enerzone/Aprilaire support that) and then if the change is unacceptable you can restore the set point in 10-15 minutes. This avoids the uncertainty in how long the manual change can remain in effect and the associated potential for short cycling.
Good point, Dan, but perhaps I wasn't being clear. I mean to send control signals to the stats, instructing them to return to my preferred settings -- not to over-ride them. That would avoid short-cycling, no? Responding to a signal from the stats rather than polling does make more sense though. Thanks.
In article , firstname.lastname@example.org (Robert L Bass) writes: | "Dan Lanciani" wrote: | >
| > Rather than that you might want to have the thermostats tell you | > when someone makes a change (Enerzone/Aprilaire support that) and | > then if the change is unacceptable you can restore the set point in | > 10-15 minutes. This avoids the uncertainty in how long the manual | > change can remain in effect and the associated potential for short | > cycling. | | Good point, Dan, but perhaps I wasn't being clear. I mean to send | control signals to the stats, instructing them to return to my | preferred settings -- not to over-ride them.
Yes, I understood.
| That would avoid | short-cycling, no?
I'm not sure. I've observed that if I change the set point of an Enerzone/Aprilaire thermostat it will sometimes change the state of the furnace or compressor outputs even if it had just done so. Normally it imposes an anti-short-cycle delay--at least if the cause of the activation is a change in room temperature. There used to be a DIP switch that selected comfort vs. efficiency and had something to do with whether it would respond in this way (it was never well documented) but that went away in newer models.
The alternative, of course, is to use temperature sensors and let the ELK take care of everything. For me that would be fine though I'm not sure my SO would like it. She loves to mess with it. Unfortunately, she's the kind of non-technical person who thinks that when you want to raise / lower the temperature in a hurry you need to set the stat at its maximum setting. No amount of explanation seems to be able to rid her of this notion. I suspect that somewhere in early childhood education there's a course that only girls take where they are given totally bogus information on HVAC, car heaters and stuff. :(
If I do go the non-stat route I'll keep the standard stats handy in case a non-nerd ever want to buy the house.