[Coco] OT: Heat / A/C controller replacement

[gene heskett]

On Thursday, June 07, 2012 10:37:14 PM Stephen H. Fischer did opine:

> Hi,
> 
> My Heat / A/C was installed ~ 1971.
> 
So?  The control interface probably hasn't changed enough to care in 60 
years.  The typical micro controlled Honeywell wall stat you can get at 
Lowes/Home Depot for 50-60 dollars still talks to the usual 24 volt control 
circuitry, 5 or 6 wires, that could very well come from a 70 year old coal 
stoker, just as easily as it hooks to my AC and a Bryant 90+ natural gas 
furnace that is now about 8 or 9 years old & vents thru 2" white PVC pipe 
out thru what used to be a basement window.  I paid $50 for this one, gives 
me 4x a day settings plus weekends.  I've replaced the 2 backup the clock 
penlight cells in it twice in 15 years.
 
> Today's Heat / A/C controllers likely have an wireless internet address.

For a price I suppose that is available, but this one I have to program 
from its panel, in person.

> I just am looking for ideas as to how a old heat / A/C controller could
> be used like the one I built ~ 30+ years ago.

If all you did was close a relay, then any of the stats available today can 
do that.

I don't think it has to be old, the actual interface itself has not 
markedly changed in yonks.  The "fan only" switch might not work. I think 
that was the last addition to the low voltage protocol, probably 40 years 
ago, if not more.  The only time I use that is if the AC freezes up the 
inside coils, then you turn off the AC and turn on the fan till it thaws 
out.
 
> Links to the old controllers available today might be a starting point.
> 
> I fear walking into a hardware store would produce smart phones to
> control Heat / A/C from Perth.
> 
> SHF
> 
> ----- Original Message -----
> From: "Louis Ciotti" <lciotti1 at gmail.com>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Thursday, June 07, 2012 6:50 PM
> Subject: Re: [Coco] OT: Heat / A/C controller replacement
> 
> >I assume you need something unique that a standard Heat/AC thermostat
> >
> > will not work?
> > 
> > 
> > 
> > On Thu, Jun 7, 2012 at 5:02 PM, Stephen H. Fischer
> > 
> > <SFischer1 at mindspring.com> wrote:
> >> Hi,
> >> 
> >> HELP!
> >> 
> >> My hand constructed Heat / A/C control failed when the power went off
> >> and it
> >> is beyond my current ability to fix it. (data sheets are hidden, I
> >> did not
> >> draw up a plan, just wired the chips up looking at the data books
> >> many decades ago.)
> >> 
> >> ---------------------------
> >> The basic operation was a LM3911 that sensed the temperature and
> >> CMOS chips drove a triac (AC power relay).
> >> 
> >> There was a pot that controlled the set point and more parts to trim
> >> the pots range and drive LED's.
> >> 
> >> ---------------------------
> >> What I am looking for is a off the shelf controller that I can change
> >> the desired temperature easily and have an off switch for use when I
> >> do not use
> >> the heat or A/C.
> >> 
> >> The present controller is just a relay that just shorts the heat /
> >> A/C power
> >> just like a switch which is how I will be doing it if an replacement
> >> cannot
> >> be found. The normal house controls are used to switch from heat to
> >> A/C and
> >> prevent the house being heated too much or cooled too much in case of
> >> a failure
> >> 
> >> It was good that the power failure did it's damage when the home-brew
> >> controller was off/
> >> 
> >> I know this is a weird request and will not make sense to those who
> >> know how
> >> heat / A/C work.
> >> 
> >> No timed options needed and other bells / chimes that the current
> >> controllers have, I want to just set the temperature and turn it on
> >> and off.
> >> 
> >> SHF
> >> 
> >> 
> >> 
> >> 
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> > 
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Cheers, Gene
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