zoned or not zoned?? thermostatic control of multiple spaces

As Marc said, you really need to find out what the system is, and how it is plumbed.

Then I would ask a knowledgeable serviceman/contractor/supplier (may also be how you find out what it is) to see if something easy can be done. It is possible that this is something relatively common and they have an obvious fix for it. Without the proper knowledge and experience, the people here could end up with something unnecessarily Rube Goldbergish in spite of the collective knowledge.

Let me get this straight. You volunteer a solution but can't provide it. Sheesh!

Jim Baber wrote: Your tenants will undoubtedly complain when their adjustments to the thermostats within their unit don't have the effect they wanted because some other thermostat overrode their changes....

I can't even get my wife to agree how to set the thermostat....

And if there was ever a fire and your n> don't know how this would be "tormenting" my tenants. it's not like i'm

Agreed. Also, almost any remote thermostat can be gamed. In an office I worked in, I shone a floor lamp on the thermostat when I wanted it cooler and hit it with a blast of canned air upside down when I wanted it warmer. Didn't matter that the thermostat was in a big, allegedly tamper-proof box. A well-bent paper clip worked wonders as well

-- Bobby G.

Heh, this is where programmable theromstats are handy. I've specifically added some set-back events timed to execute about a half-hour after the wife is known to fiddle with the thermostat. Works wonders. She'd come home and crank down the AC, in a half-hour the event would reset it to a more reasonable setting. Saved considerably in the marital bliss department.

If/when thermostats and the like get real bidirectional feedback it'd be great. It'd be great to have a CPU balance between outside ambient temperature, day/night sun conditions, occupancy and preset programming definitions. As in, detect that someone's fiddled with the thermostat, let them "get away with it" for a short while and resume settings as desired while being intelligent about it. Until then, ah well.

Thermostats that can do what you want have been available for at least a dozen years. My experience is with Aprilaire 8870 and its precursors ( formerly Enerzone /Statnet). They use RS-485 and a simple ASCII command set that can be sent from the command line, a terminal program, a VB program and is natively supported in Homerseer, CQC, CyberHouse, Premise Systems (now Motorola and defunct -- a free and presumably legal download described here:

The Aprilaire/Enerzone/Statnet command set can be used to query or set multiple single or multi-stage heat + cool thermostats, temperature or humidity sensors, dampers or other devices on the RS-485 line. There's enough capacity for expansion left in the command set and bandwidth that it would be a good candidate for a homebrew RS-485 control system with other functionality in my opinion.

... Marc Marc_F_Hult

That is one of the "primary directives" for my HA system. My sweetheart is an angel. However, she's totally non-technical and I cannot get her to understand that setting the thermostat for 78F will not make the house heat up faster. She envisions the system as though there's a flame that gets bigger when you adjust the thermostat upwards, similar to turning the gas up on the range.

My plan is to use analog temperature sensors in each zone and let the ELK M1G control the HVAC. I'll leave the existing stats powered up so she can fiddle with them but they won't control anything. :^)

This can be done using existing hardware. Connect the stats to your HA system. If someone sets the stat higher than the current setting, throw a relay allowing the stat to control the HVAC system for 30 minutes and then release the relay.

I think that this one is likely to backfire. Lots of "it must be broken, I tuned it down twice and it never came on."

That's more likely to work. The system comes on and psychologically it feels cooler.

you forget that 2 out of 3 tenants currently have no control over the temp at all. they rely on one tenant who has the thermostat in his unit to set it at a reasonable temp. My thought was to really have temp monitors in all the units and have a central thermostat (available to me) to keep the units warmer than say 68, but no hotter than 72.

Jim Baber wrote:

You might get the thermostats to implement the practical solution I suggested in an earlier post for as little as about $35.

See

in general and specifically:

This solution recognizes that your only actual control choice is ON or OFF.

Consider adding a way to sense the position of the relays and 1) log them so that you know what is 'normal' and what is extreme and 2) send you email/other notification if one or more of the TooHot or TooCold conditions is triggered.

... Marc Marc_F_Hult

thanks, marc. i'll look at that more closely.

Marc_F_Hult wrote: