I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the relative
humidity set on the H-stat. It went on to say that it helps to keep the unit
from cycling as often as it normally would, thereby saving electricity and
still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this typing.
:-)
Opinions appreciated!
TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday

1D10T wrote:

I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the relative
humidity set on the H-stat. It went on to say that it helps to keep the unit
from cycling as often as it normally would, thereby saving electricity and
still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this typing.
:-)
Opinions appreciated!
TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday


The two controls are wired in parallel (Not in series) therefore, if
either the Temperature or the Humidity set points are Not met, the AC
contactor will stay energized & the AC unit will stay running.
Especially if the system is somewhat oversized, it is a good way to go.
- udarrell

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

http://www.udarrell.com/

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

http://www.udarrell.com/principled_a...ju stice.html

http://www.udarrell.com/recognizing_real_enemies.html

http://jesuschristsavior.net/Beatitudes.html

http://www.antiwar.com/ ***

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

On Thu, 9 Aug 2007 20:19:43 -0500, "1D10T"
wrote:

I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the relative
humidity set on the H-stat. It went on to say that it helps to keep the unit
from cycling as often as it normally would, thereby saving electricity and
still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this typing.
:-)
Opinions appreciated!

It occurs to me that there would be 2 ways to connect the h-stat.

1) In parallal with the t-stat, so that the ac will run until both
standards are met. I'd have to review the thermostat wiring diagram
and how the AC works, or just wait until somene says, to know if this
is an easy thing to do, but it seems like it might be the best.

2) In series so that if either the temp or humidity is low enough the
AC turns off. I think this would be harder to do, and not what people
want anyhow.

If you use method 1, I have the feeling that one stat or the other
will dominate things. Once in a while the other stat will keep the AC
on, but after that it will be the first one to rise, the humidity or
the temperature, that will determine when the AC goes back on again.

Maybe this is usually the temp and that is why most ac run only on
t-stats. ???? I'm just speculating.


TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday

Wiring the humidistat and thermostat in parallel should theoretically work,
but.............

most humdistats are designed to *********close********* their contacts when
the humidity falls below a specific set-point (so as to energize a
humidifier) and therefore, will *******do the opposite******* of what the
original poster intended******* if wired in parallel as recommended.

What is actually needed is a humidistat which closes it contacts when the
humidity level *****rises***** above a specific set-point,. thereby
energizing the air conditioning when there is too much humidity.

Using a conventional humidistat as the prior reply indicates will ***NOT
WORK*** as claimed, and, in fact, will turn on the a/c and keep it on as the
air gets drier.......


Smarty



"udarrell" wrote in message
. net...
1D10T wrote:

I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the relative
humidity set on the H-stat. It went on to say that it helps to keep the
unit
from cycling as often as it normally would, thereby saving electricity and
still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this
typing.
:-)
Opinions appreciated!
TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday
The two controls are wired in parallel (Not in series) therefore, if
either the Temperature or the Humidity set points are Not met, the AC
contactor will stay energized & the AC unit will stay running. Especially
if the system is somewhat oversized, it is a good way to go. - udarrell

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

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

http://www.udarrell.com/principled_a...ju stice.html

http://www.udarrell.com/recognizing_real_enemies.html

http://jesuschristsavior.net/Beatitudes.html
http://www.antiwar.com/ ***

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

On Thu, 09 Aug 2007 23:08:42 -0400, mm
wrote:


1) In parallal with the t-stat, so that the ac will run until both
standards are met. I'd have to review the thermostat wiring diagram
and how the AC works, or just wait until somene says, to know if this
is an easy thing to do, but it seems like it might be the best.

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

By load, I mean the wires from the ac that go to the t-stat and which
would have gone directly to the h-stat if it weren't backwards from
you want.

By the relay on or off, I mean a simple relay that has a 24v power
supply and is turned on when the the H-stat says it should be, and off
when the h-stat says it should be. On is when the contacts in the
H-stat are closed and off is when they are open.

If they don't sell them with this relay as an attachment, it would
still be easy to get one and easy to do. I say 24 volts because there
are loads and loads of 24 volt relays and that is the voltage supplied
to the t-stat to begin with. You don't need single pole single throw,
but get DPDT anyhow for a dollar more. You'll find other uses for the
other parts. Maybe you'll want to turn an indicator light on when you
turn the AC off, or whatever.

Instead of adding a power supply and relay to invert the humidistat control,
another simpler approach would be to use a wall control which "closes" on
rising humidity such as this one which are designed for the application
requested by the original post:

http://www.amazon.com/Honeywell-H46C.../dp/B00069ECM2

Smarty



"mm" wrote in message
...
On Thu, 09 Aug 2007 23:08:42 -0400, mm
wrote:


1) In parallal with the t-stat, so that the ac will run until both
standards are met. I'd have to review the thermostat wiring diagram
and how the AC works, or just wait until somene says, to know if this
is an easy thing to do, but it seems like it might be the best.

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

By load, I mean the wires from the ac that go to the t-stat and which
would have gone directly to the h-stat if it weren't backwards from
you want.

By the relay on or off, I mean a simple relay that has a 24v power
supply and is turned on when the the H-stat says it should be, and off
when the h-stat says it should be. On is when the contacts in the
H-stat are closed and off is when they are open.

If they don't sell them with this relay as an attachment, it would
still be easy to get one and easy to do. I say 24 volts because there
are loads and loads of 24 volt relays and that is the voltage supplied
to the t-stat to begin with. You don't need single pole single throw,
but get DPDT anyhow for a dollar more. You'll find other uses for the
other parts. Maybe you'll want to turn an indicator light on when you
turn the AC off, or whatever.

On Aug 9, 10:12 pm, "Smarty" wrote:
Wiring the humidistat and thermostat in parallel should theoretically work,
but.............

most humdistats are designed to *********close********* their contacts when
the humidity falls below a specific set-point (so as to energize a
humidifier) and therefore, will *******do the opposite******* of what the
original poster intended******* if wired in parallel as recommended.

What is actually needed is a humidistat which closes it contacts when the
humidity level *****rises***** above a specific set-point,. thereby
energizing the air conditioning when there is too much humidity.

Using a conventional humidistat as the prior reply indicates will ***NOT
WORK*** as claimed, and, in fact, will turn on the a/c and keep it on as the
air gets drier.......

Smarty

"udarrell" wrote in message

. net...



1D10T wrote:

I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the relative
humidity set on the H-stat. It went on to say that it helps to keep the
unit
from cycling as often as it normally would, thereby saving electricity and
still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this
typing.
:-)
Opinions appreciated!
TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday
The two controls are wired in parallel (Not in series) therefore, if
either the Temperature or the Humidity set points are Not met, the AC
contactor will stay energized & the AC unit will stay running. Especially
if the system is somewhat oversized, it is a good way to go. - udarrell

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

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

http://www.udarrell.com/principled_a...s_administrati...

http://www.udarrell.com/recognizing_real_enemies.html

http://jesuschristsavior.net/Beatitudes.html
http://www.antiwar.com/***

Reality Is Not An Easy Thing To Be Confronted With, or to Accept!- Hide quoted text -

- Show quoted text -


And if the system only ran to reach the desired humidity level, why
would you need the thermostat at all? One would think that in a
period when you have a temp humidity index of 110-115, which sounds
like a jungle, that any reasonable AC system would have dropped the
humidity to a comfortable level before reaching 70 deg., which sounds
mighty coool. If you want to save money and time, just raise the
thermostat to 75 or higher, which should still feel like a freezer if
you really have a 110-115 THI outside.

On Fri, 10 Aug 2007 02:45:58 -0400, "Smarty"
wrote:

Instead of adding a power supply and relay to invert the humidistat control,
another simpler approach would be to use a wall control which "closes" on

I suggested what I did because of your post at xx:12 o'clock which
said that a conventional humidistat would not work, and implied that
the reply previous to that post suggested a conventional humidistat.

You said what was needed was the opposite, but didn't actually say
they made such things.

So I was saying that if, as I gleaned from your post, they don't make
the kind of humidistat that you say is needed, then you can add a
relay to use the kind they do make. I think the relay would only cost
about 4 dollars.

rising humidity such as this one which are designed for the application
requested by the original post:

http://www.amazon.com/Honeywell-H46C.../dp/B00069ECM2

So this one would work in parallel with a thermostat, as udarrell
suggested, no other parts needed? Great.

I guess to simplify this, For use when it is too humid, be sure to get
a humidistat for a dehumidifier and not one for a humidifier.


Smarty



"mm" wrote in message
.. .
On Thu, 09 Aug 2007 23:08:42 -0400, mm
wrote:


1) In parallal with the t-stat, so that the ac will run until both
standards are met. I'd have to review the thermostat wiring diagram
and how the AC works, or just wait until somene says, to know if this
is an easy thing to do, but it seems like it might be the best.

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

By load, I mean the wires from the ac that go to the t-stat and which
would have gone directly to the h-stat if it weren't backwards from
you want.

By the relay on or off, I mean a simple relay that has a 24v power
supply and is turned on when the the H-stat says it should be, and off
when the h-stat says it should be. On is when the contacts in the
H-stat are closed and off is when they are open.

If they don't sell them with this relay as an attachment, it would
still be easy to get one and easy to do. I say 24 volts because there
are loads and loads of 24 volt relays and that is the voltage supplied
to the t-stat to begin with. You don't need single pole single throw,
but get DPDT anyhow for a dollar more. You'll find other uses for the
other parts. Maybe you'll want to turn an indicator light on when you
turn the AC off, or whatever.

mm wrote:

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

Ignore Smarty. Just buy the right kind, eg Honeywell's H46C1166...

http://www.grainger.com/Grainger/wwg...mId=1611632220

Nick

Yes, a "dehumidistat" (not a commonly used term or commonly found item)
would work without the need for extra power or relay, and your solution does
indeed allow a standard "humidistat" to be used as well. Both are workable
solutions.

Smarty


"mm" wrote in message
...
On Fri, 10 Aug 2007 02:45:58 -0400, "Smarty"
wrote:

Instead of adding a power supply and relay to invert the humidistat
control,
another simpler approach would be to use a wall control which "closes" on

I suggested what I did because of your post at xx:12 o'clock which
said that a conventional humidistat would not work, and implied that
the reply previous to that post suggested a conventional humidistat.

You said what was needed was the opposite, but didn't actually say
they made such things.

So I was saying that if, as I gleaned from your post, they don't make
the kind of humidistat that you say is needed, then you can add a
relay to use the kind they do make. I think the relay would only cost
about 4 dollars.

rising humidity such as this one which are designed for the application
requested by the original post:

http://www.amazon.com/Honeywell-H46C.../dp/B00069ECM2

So this one would work in parallel with a thermostat, as udarrell
suggested, no other parts needed? Great.

I guess to simplify this, For use when it is too humid, be sure to get
a humidistat for a dehumidifier and not one for a humidifier.


Smarty



"mm" wrote in message
. ..
On Thu, 09 Aug 2007 23:08:42 -0400, mm
wrote:


1) In parallal with the t-stat, so that the ac will run until both
standards are met. I'd have to review the thermostat wiring diagram
and how the AC works, or just wait until somene says, to know if this
is an easy thing to do, but it seems like it might be the best.

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

By load, I mean the wires from the ac that go to the t-stat and which
would have gone directly to the h-stat if it weren't backwards from
you want.

By the relay on or off, I mean a simple relay that has a 24v power
supply and is turned on when the the H-stat says it should be, and off
when the h-stat says it should be. On is when the contacts in the
H-stat are closed and off is when they are open.

If they don't sell them with this relay as an attachment, it would
still be easy to get one and easy to do. I say 24 volts because there
are loads and loads of 24 volt relays and that is the voltage supplied
to the t-stat to begin with. You don't need single pole single throw,
but get DPDT anyhow for a dollar more. You'll find other uses for the
other parts. Maybe you'll want to turn an indicator light on when you
turn the AC off, or whatever.

Nick,

If you "ignore Smarty" and use the original parallel combination of t-stat
and h-stat which was incorrectly recommended, you wind up with a system that
switches the a/c off as the humidity rises, and thus does exactly the
opposite of what is required.

My suggestion was (and is) to avoid adding an extra relay and power source
by choosing the correct type of control, namely, the Honeywell I recommended
or something equivalent to it. A parallel connection in this case will work
exactly as expected, namely to turn on the a/c when either the temperature
or the humidity level called for additional refrigeration.

I thus do not understand your recommendation to "ignore Smarty".

Could you please clarify?

Thanks,

Smarty






wrote in message
...
mm wrote:

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

Ignore Smarty. Just buy the right kind, eg Honeywell's H46C1166...

http://www.grainger.com/Grainger/wwg...mId=1611632220

Nick

Smarty wrote:

Wiring the humidistat and thermostat in parallel should theoretically work,
but.............

most humdistats... -

(That is a Dehumidifier "DeHumidistat" for the Cooling Mode, "Not the Heating Mode Humidifier Humidistat.")

- ... are designed to *********close********* their contacts when the humidity falls below a specific set-point (so as to energize a
humidifier) and therefore, will *******do the opposite******* of what the
original poster intended******* if wired in parallel as recommended.


The room TH has two Modes - Heating & Cooling, in the cooling mode,
wired parallel, the circuit would stay closed until the Setpoints of
both sensible temp & % RH were met.
In the Heating mode the Humidistat contacts would work the opposite way
& close to bring the humidifier on when the RH got too low.
Because Heat & Cool are separate circuits', each separate circuit can be
"wired in parallel to do different or opposite things.
The Humidity controller in each separate circuit is engineered to
perform differently, in the Heating Mode the Humidistat contacts are
open until the low %RH setpoint is reached & then the contacts close
bringing on the humidifier. The "Cooling Mode Dehumidification
controller & circuitry" works the opposite.

If they are wired in series, as soon as one of the two setpoints' is
reached the control circuit to the contactor in the cooling AC mode
would open shutting it off before the other setpoint was reached. The
entire purpose is to keep the AC running until both comfort level
setpoints are reached. The setpoints of the individual RM TH & the
dehumidistat can be set at a point where the individual wants each one
for their desired comfort in either the Cooling or Heating Modes.

There should also be a differential settings on both setpoints so the
controller can eliminate short cycling, especially of the AC in the
Cooling Mode.
http://www.udarrell.com/air-conditio...tent-heat.html

- udarrell

What is actually needed is a humidistat which closes it contacts when the
humidity level *****rises***** above a specific set-point,. thereby
energizing the air conditioning when there is too much humidity.

Using a conventional humidistat as the prior reply indicates will ***NOT
WORK*** as claimed, and, in fact, will turn on the a/c and keep it on as the
air gets drier....... Smarty


Sorry Smarty, but that is NOT the way the two separate circuitry's of
separate Heating & Cooling Modes will be wired. (See Above.)
- udarrell

"udarrell" wrote in message
.net...


1D10T wrote:


I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the relative
humidity set on the H-stat. It went on to say that it helps to keep the
unit


from cycling as often as it normally would, thereby saving electricity and


still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this
typing.
:-)
Opinions appreciated!
TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday


The two controls are wired in parallel (Not in series) therefore, if
either the Temperature or the %Relative Humidity set points are Not met, the AC
contactor will stay energized & the AC unit will stay running. Especially
if the system is somewhat oversized, it is a good way to go. - 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!

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 humidistat
and thermostat was all that was needed, and the lower of the two setpoints
would then properly control the air conditioner.

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



question and discussion never asked about heating. It asked about how to
control air conditioning using both a thermostat and a humidistat.
"udarrell" wrote in message
et...
Smarty wrote:

Wiring the humidistat and thermostat in parallel should theoretically
work, but.............

most humdistats... -

(That is a Dehumidifier "DeHumidistat" for the Cooling Mode, "Not the
Heating Mode Humidifier Humidistat.")

- ... are designed to *********close********* their contacts when the
humidity falls below a specific set-point (so as to energize a humidifier)
and therefore, will *******do the opposite******* of what the original
poster intended******* if wired in parallel as recommended.
The room TH has two Modes - Heating & Cooling, in the cooling mode, wired
parallel, the circuit would stay closed until the Setpoints of both
sensible temp & % RH were met.
In the Heating mode the Humidistat contacts would work the opposite way &
close to bring the humidifier on when the RH got too low.
Because Heat & Cool are separate circuits', each separate circuit can be
"wired in parallel to do different or opposite things.
The Humidity controller in each separate circuit is engineered to perform
differently, in the Heating Mode the Humidistat contacts are open until
the low %RH setpoint is reached & then the contacts close bringing on the
humidifier. The "Cooling Mode Dehumidification controller & circuitry"
works the opposite.

If they are wired in series, as soon as one of the two setpoints' is
reached the control circuit to the contactor in the cooling AC mode would
open shutting it off before the other setpoint was reached. The entire
purpose is to keep the AC running until both comfort level setpoints are
reached. The setpoints of the individual RM TH & the dehumidistat can be
set at a point where the individual wants each one for their desired
comfort in either the Cooling or Heating Modes.

There should also be a differential settings on both setpoints so the
controller can eliminate short cycling, especially of the AC in the
Cooling Mode.
http://www.udarrell.com/air-conditio...tent-heat.html
- udarrell
What is actually needed is a humidistat which closes it contacts when the
humidity level *****rises***** above a specific set-point,. thereby
energizing the air conditioning when there is too much humidity.

Using a conventional humidistat as the prior reply indicates will ***NOT
WORK*** as claimed, and, in fact, will turn on the a/c and keep it on as
the air gets drier....... Smarty
Sorry Smarty, but that is NOT the way the two separate circuitry's of
separate Heating & Cooling Modes will be wired. (See Above.)
- udarrell

"udarrell" wrote in message
s.net...

1D10T wrote:

I read that if you set the T-stat to 70º and the H-stat to what you
*perceive* to be a comfort level, the AC only runs to achieve the
relative
humidity set on the H-stat. It went on to say that it helps to keep the
unit

from cycling as often as it normally would, thereby saving electricity
and

still be comfortable. The THI here for a week has been 110 - 115, and it
just got me to wondering. As inexpensive as the H-stats are I thought it
would be worth a try - or at least the time it takes to do all this
typing.
:-)
Opinions appreciated!
TIA
- - - - - - - - - - - - - - - - - - -
Easy's gettin' harder everyday

The two controls are wired in parallel (Not in series) therefore, if
either the Temperature or the %Relative Humidity set points are Not met,
the AC contactor will stay energized & the AC unit will stay running.
Especially if the system is somewhat oversized, it is a good way to go. -
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!

On Aug 10, 9:24 am, "Smarty" wrote:
Nick,

If you "ignore Smarty" and use the original parallel combination of t-stat
and h-stat which was incorrectly recommended, you wind up with a system that
switches the a/c off as the humidity rises, and thus does exactly the
opposite of what is required.

My suggestion was (and is) to avoid adding an extra relay and power source
by choosing the correct type of control, namely, the Honeywell I recommended
or something equivalent to it. A parallel connection in this case will work
exactly as expected, namely to turn on the a/c when either the temperature
or the humidity level called for additional refrigeration.

I thus do not understand your recommendation to "ignore Smarty".

Could you please clarify?

Thanks,

Smarty

wrote in message

...



mm wrote:

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

Ignore Smarty. Just buy the right kind, eg Honeywell's H46C1166...

http://www.grainger.com/Grainger/wwg...shtml?ItemId=1...

Nick- Hide quoted text -

- Show quoted text -


While everyone is engineering away, am I the only one wondering why
anyone would be worrying about a humidistat solution for a 110-115THI
outside environment, with the insidethermostat set to 70? In that
environment, any properly functioning AC system is going to run enough
(like all the time) to keep the temp under control that it will reduce
the humidity, without any help from a humidistat. And why you;d need
a set temp of 70 in that jungle environment is beyond me. When it's
humid and 85 outside, I set mine to about 76 and it feels nice and
cool. And that nowhere near the 115THI level.

There are high end thermostats that include humidity control, which is
what you want instead of some half assed glued together widget. But
I think they are targeted at systems that include a variable speed
blower. So, if the system gets close to the set temp, but the
humidity is still too high, it will run the blower at slow speed so it
takes more moisture out before reaching the desired temp. That makes
sense. Putting a humidistat in parallel with the thermostat does
not. How are you going to feel if the room temp goes down to 62 to
get the desired humidity?

In short, I think the OP is looking for a solution to a problem that
doesn't exist.

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!

wrote:

On Aug 10, 9:24 am, "Smarty" wrote:


Nick,

If you "ignore Smarty" and use the original parallel combination of t-stat
and h-stat which was incorrectly recommended, you wind up with a system that
switches the a/c off as the humidity rises, and thus does exactly the
opposite of what is required.

My suggestion was (and is) to avoid adding an extra relay and power source
by choosing the correct type of control, namely, the Honeywell I recommended
or something equivalent to it. A parallel connection in this case will work
exactly as expected, namely to turn on the a/c when either the temperature
or the humidity level called for additional refrigeration.

I thus do not understand your recommendation to "ignore Smarty".

Could you please clarify? Thanks, Smarty

While everyone is engineering away, am I the only one wondering why
anyone would be worrying about a De-humidistat solution for a 110-115THI
outside environment, with the inside thermostat set to 70? In that
environment, any properly functioning AC system is going to run enough
(like all the time) to keep the temp under control that it will reduce
the humidity, without any help from a De-humidistat. And why you;d need
a set temp of 70 in that jungle environment is beyond me. When it's
humid and 85 outside, I set mine to about 76 and it feels nice and
cool. And that nowhere near the 115THI level.

There are high end thermostats that include humidity control, which is
what you want instead of some half assed glued together widget. But
I think they are targeted at systems that include a variable speed
blower. So, if the system gets close to the set temp, but the
humidity is still too high, it will run the blower at slow speed so it
takes more moisture out before reaching the desired temp. That makes
sense. Putting a De-humidistat in parallel with the thermostat does
not. How are you going to feel if the room temp goes down to 62 to
get the desired humidity?


Trader4, good point(s), in that situation, I would say the AC is too
oversized to achieve the application goals.
Also, if the lower blower speeds will achieve a tolerable CFM airflow,
one can use relays to change to a lower blower speed tap even with a
regular multiple speed motor. Where there are humidity problems the
Entire System Design has to address that problem to work properly.

In short, I think the OP is looking for a solution to a problem that
doesn't exist. (Right-On!)


At those temps, you are certainly correct!
Yes, in some applications they also slow the blower down until a %RH
setpoint is reached.
- 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!

I have some $5 Navy surplus humidistats with both NO and NC terminals. Some
line-voltage thermostats do too. For constant-temp dehumidification, we might
put one $80 AC in a window and one in the basement and wire the window AC
to the close-on-rise contact of Grainger's $16 2E158 SPDT thermostat and
the other to the close-on-fall contact and run the common to Grainger's $60
2E574 (Honeywell H46C1166) "dehumidification control."

Nick

Nick,

If you "ignore Smarty" and use the original parallel combination of t-stat
and h-stat which was incorrectly recommended, you wind up with a system that
switches the a/c off as the humidity rises, and thus does exactly the
opposite of what is required.

My suggestion was (and is) to avoid adding an extra relay and power source
by choosing the correct type of control, namely, the Honeywell I recommended
or something equivalent to it. A parallel connection in this case will work
exactly as expected, namely to turn on the a/c when either the temperature
or the humidity level called for additional refrigeration.

I thus do not understand your recommendation to "ignore Smarty".

Could you please clarify?

Thanks,

Smarty


wrote in message
...
mm wrote:

To add to my post: To compensate for what Smarty says, you would need
to put in a 24 volt relay in the h-stat that would turn the load off
when the relay is on, and turn the load on when the relay is off.

Ignore Smarty. Just buy the right kind, eg Honeywell's H46C1166...

http://www.grainger.com/Grainger/wwg...mId=1611632220

Nick