Lately friend of mine installed digital thermostat for me replaced
With old one it worked fine until when I turned the heater on
Smoke came out of the thermostat I didn't even call him
I took every thing in part to see what is wrong this is what
I found.

------ common
------ heat
------ compressor only
------ fan only
------ AC 24 v
------ AC 24 V

when I connect common to heat wire or other wire it works fine.
On thermostat board there are 3 or 4  relays they are using relays
To turn on and off. When you make your thermostat

Input voltage: AC 24
Heat: use small relay:
Fan: use small relay
Compressor: use small relay
Cold: use fan and compressor relay together

When you built one let me know I like to built one for me too.
Hope this helps
Andre Abelian





Thinking to build a home made temperature control for the "home AC".
Any hint where I can find some description of the wiring coming to the
actual thermostate box?

It seems to be the most common type of controls, COOL-OFF-HEAT
AUTO-FAN-ON
and the temperature lever that changes the thermostate mercury switches.
Coming 9 wires from the cable, 8 used.  There is a name "TRANE" printed
on
front panel.

I guess we may have power in some wire that can be regulated to feed
some
uC.
Small relays and temp sensors could be a good job in saving energy
during
the non-necessary time of the day, including remote programming via
phone
DTMF (on/off, set temp, etc).

I also noticed that there is a variable resistor inside, probably to set
up
the auto-fan timer.

Any hint will be appreciated.
VV46NER.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu