Thread: Question about 2 stage AC/Heat Pump
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dpb dpb is offline
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Default Question about 2 stage AC/Heat Pump
wrote:
....

Am I the only one wondering what sense it makes for the heat pump to
always start on stage 1 for 10 mins, then move to stage 2? It would
seem in any properly sized system, 10 mins of AC run time would rarely
be enough to cool the house even 1 degree. And in any case, it
would seem the thermostat would be smart enough to have a better way
of figuring out what stage to start at, eg the current temp delta, how
hot it is etc. Seems strange to waste 10 mins on stage 1 if the
house is 85.

I was _presuming_ (dangerous, I know... ) that there's more to the
control logic than simply time but wasn't interested enough to either
try to look up the thermostat datasheet or ask the OP...

I think this is one of those that has a "self-learning" mode that is
based on several inputs the demand dT being only one and they also use
previous heating/cooling "histories" to try to find a site-specific
strategy. How well they'll work in practice will be dependent on just
how clever the programming was and the suitability to the particular
installation.

I've never actually had one; only read about some of the logic designs
in a few of the engineering trade magazines. My general impression has
been they seemed too gimmicky to be of much real value in comparison to
more simple control schemes w/ setback so that I really wondered if they
could demonstrate any actual advantage to speak of or whether were more
marketing/feature-rich driven.

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