Smarty wrote:

udarrell,

This original poster's question was very simple and asked how a humidistat
could possibly be used to save air conditioning cost / lower electric
consumption by cycling the a/c based on humidity as well as temperature. The
incorrect reply someone offered was that a parallel connection of (DE-humidistat)
and thermostat was all that was needed, and the lower of the two setpoints
would then properly control the air conditioner. (Again, that should have been 'DE-humidistat')


Anyway, we both know how it should be wired to achieve our intended
purposes.
I apologize to you Smarty, I only view posts that have not been read.
He misstated when he said humidistat instead of a dehumidistat, or
Thermidistat.
I would only use a control designed to accomplish the intended purpose.
It's okay Smarty, it simply appears there were a lot of misstating a
humidistat when they may have meant de-humidistat.
- udarrell

I raised the concern in my post that merely connecting the two controls in
parallel would not work. This is very simply because a standard humidistat
closes its' contacts when the humidity drops, and thus, in a parallel
arrangement someone else suggested, switches in the exact opposite sense
from the desired opening of its' contacts. As the humidity dropped, the
humidistat would continuously call for more cooling, and the a/c/ would run
on wasting huge electricity and over cooling in the process.

The subsequent "improvement" to this approach offered by someone else was to
then add a relay and power source, to invert the humidistat switch closure,
so that dropping humidity which closed the humidistat would then open a set
of relay contacts. This would indeed correct the original design mistake
originally made by whomever offered it.

I replied to offer the suggestion that a Honeywell dehumidifier control such
as the one I cited at Amazon would switch correctly, and avoid the need for
a relay or additional power altogether. In fact, this type of
dehumidification control is designed specifically to switch a system "OFF"
when the humidity level is lowered, exactly what is needed in this case.

This was NEVER a discussion of room heating thermostats, or had any
reference whatsoever to what could or should be done in a more complex
system with a furnace, humidifier, etc. You are certainly correct that
****IF**** the original question were to be asked as to how to configure a
thermostat and humidistat for all season control of furnace, humidifier, air
conditioning, etc., then a different approach would most certainly be
warranted.

This was, however, not the question which was originally asked. Nor were the
replies intended to answer this different question. Smarty


You are right Smarty the poster' called a de-humidistat a humidistat.
The original poster probably meant dehumidistat.
Some call the combo a thermidistat, etc. - udarrell

--
WISDOM PRINCIPLE DIRECTED EMPOWERMENT COMMUNICATIONS -
THE REAL POLITICAL ISSUES and WISDOM BASED PEOPLE EMPOWERMENT

http://www.udarrell.com/my_pages2.htm
(* My Airconditioning Links, Hunting Shooting, Angus Cattle, etc.)

Reality Is Not An Easy Thing To Be Confronted With, or to Accept!