Reply by Dan Purgert February 19, 20212021-02-19
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Olden wrote:
> Best to ask here or ? > > My gas furnace is a Holly. > It has an old mercury two wire thermostat. > > I want to change the thermostat so that I can set the same two > temperature ranges, day / night, for every day. > > I do not understand thermostats. > > The local store does not know how to advise me. > > Thermostat suggestions please and maybe a little tutorial.
The major thing you need to know is the control voltage - that SHOULD be stamped / molded into your existing thermostat. After that, it's a quick wire-for-wire swap -- check the existing, it's probably labeled as "W" / "R" (for "White" and "Red" wire, respectively). Connect those wires coming out of the wall to the same terminals of the new thermostat (ignore Y/B/etc, as those connections are for cooling / multi-stage heat / etc.). Then program the thing for whatever temperatures you want.
>
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Reply by whit3rd February 19, 20212021-02-19
On Thursday, February 18, 2021 at 4:19:01 PM UTC-8, Olden wrote:
> I need to buy on-line. > Any model numbers ? > What terminology do I look for ?
Almost any 'smart' thermostat can do a daily fallback, but this does mean it's a display-and-buttons-and-clock elaborate item. Honeywell is a big manufacturer, their web site should give you some ideas <https://honeywellstore.com/store/products/wi-fi-7-day-programmable-thermostat-honeywell-rth6580wf.htm> Look at a few, and maybe check out the manuals online.
Reply by Olden February 18, 20212021-02-18
I need to buy on-line.
Any model numbers ?
What terminology do I look for ?

Please help.


danny burstein wrote:
> In <602c5820$0$27446$e4fe514c@textnews.kpn.nl> Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> writes: > >> On 16.02.21 21:55, Olden wrote: >>> Best to ask here or ? >>> >>> My gas furnace is a Holly. >>> It has an old mercury two wire thermostat. >>> >>> I want to change the thermostat so that I can set the same two >>> temperature ranges, day / night, for every day. >>> >>> I do not understand thermostats. >>> >>> The local store does not know how to advise me. > > There are (or at least were...) plenty of thermostats > with multiple settings that followed the time of > day and used a battery to operate the clock, hence > could be hooked up to a basic two-wire control system > and not worry about wiring for power. >
Reply by Evgeniy February 17, 20212021-02-17
Hello, Olden!

On Tue, 16 Feb 2021 12:55:07 -0800
Olden <Olden@Olden.com> wrote:

> Best to ask here or ? > > My gas furnace is a Holly. > It has an old mercury two wire thermostat. > > I want to change the thermostat so that I can set the same two > temperature ranges, day / night, for every day. >
Just an idea: you can use two thermostats and mechanical 24 hour timer to switch them. Something like that: https://www.theben.de/en/syn-161-d-1610011 Timers can be different, with different outputs (output relay type/voltage/current, etc), this is just an example. If you do not need precision time keeping on power loss, it's preferable to use a timer without battery (no potential battery leaking out). I do not know your schematics and may be any safety limits, so it's just an idea. ------ With Best Regards, Evgeniy
Reply by danny burstein February 16, 20212021-02-16
In <602c5820$0$27446$e4fe514c@textnews.kpn.nl> Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> writes:

>On 16.02.21 21:55, Olden wrote: >> Best to ask here or ? >> >> My gas furnace is a Holly. >> It has an old mercury two wire thermostat. >> >> I want to change the thermostat so that I can set the same two >> temperature ranges, day / night, for every day. >> >> I do not understand thermostats. >> >> The local store does not know how to advise me.
There are (or at least were...) plenty of thermostats with multiple settings that followed the time of day and used a battery to operate the clock, hence could be hooked up to a basic two-wire control system and not worry about wiring for power. -- _____________________________________________________ Knowledge may be power, but communications is the key dannyb@panix.com [to foil spammers, my address has been double rot-13 encoded]
Reply by amdx February 16, 20212021-02-16
On 2/16/2021 2:55 PM, Olden wrote:
> Best to ask here or ? > > My gas furnace is a Holly. > It has an old mercury two wire thermostat. > > I want to change the thermostat so that I can set the same two > temperature ranges, day / night, for every day. > > I do not understand thermostats. > > The local store does not know how to advise me. > > Thermostat suggestions please and maybe a little tutorial. >
The easy way is to have two thermostat and a switch. Have one adjusted for day and the other for night and day/night switch to go between them. It gets more complicated if you have an air conditioner to deal with. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by Sjouke Burry February 16, 20212021-02-16
On 16.02.21 21:55, Olden wrote:
> Best to ask here or ? > > My gas furnace is a Holly. > It has an old mercury two wire thermostat. > > I want to change the thermostat so that I can set the same two > temperature ranges, day / night, for every day. > > I do not understand thermostats. > > The local store does not know how to advise me. > > Thermostat suggestions please and maybe a little tutorial. >
It would be nice to know the open voltage and the switch current when closed. Around 24 volts any ordinary programmable thermostat unit might do.
Reply by Olden February 16, 20212021-02-16
Best to ask here or ?

My gas furnace is a Holly.
It has an old mercury two wire thermostat.

I want to change the thermostat so that I can set the same two 
temperature ranges, day / night, for every day.

I do not understand thermostats.

The local store does not know how to advise me.

Thermostat suggestions please and maybe a little tutorial.