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

[Stephen H. Fischer]

Hi,
> This sounds like what you have done is remoted the thermostatic on/off
> up to the second floor so you do not have to go down stairs to adjust
> the temperature but basically making/breaking the power connection to
> the main first floor thermostat.

Precisely.

> Then you said "that has switches to select heat or A/C mode which must
> match what the downstairs original controller is set to."

The downstairs controller is still in control so the mode of heat / A/C must 
be set with it.
My hack has switches to close the relay either when it is too hot or too 
cool. When the pilot light is turned off both the hack and downstairs 
controller mode is set to A/C. When the pilot light is turned on both are 
set to heat.

> So if the homebrew on is set to
> heat at the original one is set to AC what happens?

Nothing good! If heating is set on the downstairs controller and A/C on the 
hack, the hack will be waiting for the room to cool to break the circuit 
which will not happen. Actually the temperature sensor in the downstairs 
control will open and stop the heat. This was done as a safety feature. The 
downstairs controller also operates as a safety limit to prevent over 
cooling.

When the power failure happened the hack was off due to a switch that does 
not allow it to close the circuit. Both the hack and the downstairs 
controllers were set for A/C and I had not used the A/C for two or more 
weeks.

Sunday may be hot so I will need to turn the A/C on with a simple switch and 
perhaps fiddle with the downstairs controller's A/C limit, but that is not a 
good process as the downstairs and upstairs temperatures are so different. 
That's why I built the hack, I want the upstairs to be at the desired 
temperature, the downstairs I spend little time in.

There are also several LED lights and a delay circuit in the hack. The delay 
is necessary as you may kill your A/C if you turn it on before 3 - 4 minutes 
have passed. #2 A/C $2K paid as I did not have this delay. #3 A/C $2K paid 
even though I had the delay circuit. A cleaner was added to the compressor 
and it has been working for ~ a decade.

So, cost of the hack box, > $4K.

On Fri, Jun 8, 2012 at 8:03 AM, Jim Hickle <jlhickle at yahoo.com> wrote:
> Now that I am older, I would probably just put a thermostat on each floor 
> and walk between them and switch manually.
>> BUT the problem is, how do you connect TWO of these with 5-6 wires at the 
>> SAME time.

Tell me how to do this and I will look into it. I could not understand the 
heat / A/C diagram back in the seventies and still do not understand it. I 
just found it but scanning it may not work due to age / dirt and recessed in 
a frame.

1) I am thinking about how to repair the hack, no contact cleaner left and I 
cannot drive.
The trimmer that I think has gone bad is to control the hysteresis. Another 
pot sets the operating voltage which also needs to be sprayed. The main 
temperature setting pot is hard to spray into.
I will at some time be trying different CMOS ICs and the timer chip. But the 
action of the LED's say it is the basic temperature circuit (See LM3911 data 
sheet)

2) Replacing the hack with a simple A/C sensor for now.

3) If it can be done, put two 5-6 wire controllers on each floor for the 
next owner. But then when I die, everything must be replaced and the Heat / 
A/C should be on the list. I will say yes if I can talk, but that may not be 
possible. If I can, the wires I added will be removed from the heat / A/C as 
they will not be understood.

SHF

----- Original Message ----- 
From: "Louis Ciotti" <lciotti1 at gmail.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Friday, June 08, 2012 6:25 AM
Subject: Re: [Coco] OT: Heat / A/C controller replacement

Hmmm I know this is an OT thread, but I am still trying to figure out
what the homebrewed second controller actually does. From your
description it is confusing.

You said "What I have done is break the power lead to that controller
and control the power to it using a home built temperature controller"

This sounds like what you have done is remoted the thermostatic on/off
up to the second floor so you do not have to go down stairs to adjust
the temperature but basically making/breaking the power connection to
the main first floor thermostat.

Then you said "that has switches to select heat or A/C mode which must
match what the downstairs original controller is set to."

This is the confusing part, what do the switches do if they have to
match the first floor controller. So if the homebrew on is set to
heat at the original one is set to AC what happens?


On Fri, Jun 8, 2012 at 8:03 AM, Jim Hickle <jlhickle at yahoo.com> wrote:
> Now that I am older, I would probably just put a thermostat on each floor 
> and walk between them and switch manually. I think I understand why you 
> wired it the way you did. I once had a '72 Cutlass with AM radio, FM 
> converter, 8-track player, cassette player and CB. All of it was wired 
> with relays to switch the speakers to the active device. And some had to 
> be turned on in a particular order. My dad couldn't understand why I 
> wouldn't just turn things on and off myself. Now << I >> don't understand 
> why folks can't just walk across the room to change the TV channel. Knobs, 
> darn it! I want things to have knobs again.
>
>
> --- On Thu, 6/7/12, Stephen H. Fischer <SFischer1 at Mindspring.com> wrote:
>
> From: Stephen H. Fischer <SFischer1 at Mindspring.com>
> Subject: Re: [Coco] OT: Heat / A/C controller replacement
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Date: Thursday, June 7, 2012, 11:13 PM
>
> Hi,
>
> If I was talking about the heat / AC control that was installed downstairs 
> ~ 1970, then a simple replacement like you suggest would work.
>
> BUT the problem is, how do you connect TWO of these with 5-6 wires at the 
> SAME time.
>
> If there is an understandable diagram online then I might be able to 
> figure out what I did, looking at the wires connected to the heat / A/C it 
> is puzzling to me right now what I did.
>
> I just have two wires that when shorted turn the heat or A/C on. The 
> downstairs controller sets the mode and will turn the heat / A/C off it 
> it's setting is exceeded.
>
> SHF
>