On 1/29/2015 11:08 PM, gary wrote:
Looking for a thermostat that will allow the temp to be set up or
down temporarily, and after an interval, will reset to the
pre-programmed temp.

Also, to enable/disable the whole house fan, then also, after an
interval, reset to programmed value.

Not finding what I need on the internet, probably because I don't know
what it's called or described.

thanks

gary


I see this as a pretty simple setup.

Remember that most home thermostats have a 12 volt signal from a relay.

Two thermostats set to different temperatures.

A simple switch to select one thermostat's output, or the other would
let you step up/down. But it could not handle the interval for the
temporary change.

So the micro (with a small relay output) is acting as the timer to
change back.

A button (MC) for "Temporary" would cause it to select the other thermostat.

After the time ran out, it would change back to the first thermostat.

Another switch (SPDT rather than button) could be used to decide it the
system is supposed to be shut down for an interval, or just change temp.

I suppose it wouldn't have to be a micro - if a mechanical timer could
be found that can switch thermostats.

A second mechanical timer could be wired to do the shutdown-for-a-while
thing. All it has to do it not pass through the thermostat signal for a
while...