On Fri, 24 Apr 2020 02:10:41 -0400, Clare Snyder
wrote:

On Thu, 23 Apr 2020 23:37:48 -0400, wrote:

On Thu, 23 Apr 2020 16:25:39 -0400, Clare Snyder
wrote:

On Thu, 23 Apr 2020 12:02:39 -0500, Mark Lloyd
wrote:

On 4/23/20 10:29 AM, micky wrote:
Another problem with getting a heat pump is that the wirign to the
thermostat is inadequate. no easy way to run a new wire to the same
location**.

I don't have a heat pump, but 2 stage AC and heat. This requires 7 wires
(including power return) to the thermostat. I now have 10 wires
installed (3 for later use).

I have a 2 stage furnace plus AC running on 4 wires - using a single
stage thermostat.

1) I know they make wireless thermostats and wifi thermostats, but I
wonder if they made ones that are wired but can get by on only 4 wires,
maybe by modulating the signal or something, and demodulating it at the
furnace end.

I have seen one of those. It has a unit next to the furnace, and the
connection to the wall unit works like USB USB (2 wires for power, and 2
for data). I don't remember brand/model.

2) Also, a much harder question: For years I've been looking for this,
a setback thermostat that had a Next button. So if you come home early,
leave early, go to bed or get up early, instead of having to use the up
or down button and count how mnay degrees you set the temp up or down,
you push one button once, to go to the next time period/temparature.

My thermostat doesn't have that, just the manual override (temporary
(changes to schedule at next scheduled time) or permanent).

[snip]

The problem is, with a heat pump you need W1 and W2, that makes 5. One
will start the heat pump compressor and if it can't make the stat - 10
degrees or something W2 kicks the heat strips on. You really need 2
wires for that (plus the hot, cool and fan).
If you just want your furnace to be a single stage, that's OK but in
Bal'mer he will need that toaster wire if he is not burning oil.

My 2 stage furnace has "smarts" built in that allow it to function as
a 2 stage furnace with a single stage thermostat. If it has ti run
longer than a certain time it kicks onto high. It id a Tempstar.

No reason a heat pump can't do the same. If when the heat pump starts
it cannot produce a temperature rise of X degrees in a given time it
turns on the aux heat. It's a pretty simple control algorythm

I assume they could but I haven't seen one that did.