Given this wiring diagram

http://www.patriot-supply.com/files/...-22528-02).pdf

there's no connection for a humidifier, is there...?

My brain is working slowly this morning and I'm annoyed at having to
search all over the place for part nos. etc.

this is for a Rheem RGEB-06EC-FS furnace which apparently uses a
47-22481-81 fan control board. The "Honeywell S-890G" has been replaced
at some point with a S8910U. The schematic on the actual cover is
slightly different from the PDF and labels the blower control as a
"Honeywell ST780C" (or maybe 788? I took a photo of it and reinstalled;
photo is not as clear as it could be) Also "IDM board" is not present
on schematic on cover.

thanks

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On 10/23/2011 11:46 AM, Nate Nagel wrote:
Given this wiring diagram

http://www.patriot-supply.com/files/...-22528-02).pdf


there's no connection for a humidifier, is there...?

My brain is working slowly this morning and I'm annoyed at having to
search all over the place for part nos. etc.

this is for a Rheem RGEB-06EC-FS furnace which apparently uses a
47-22481-81 fan control board. The "Honeywell S-890G" has been replaced
at some point with a S8910U. The schematic on the actual cover is
slightly different from the PDF and labels the blower control as a
"Honeywell ST780C" (or maybe 788? I took a photo of it and reinstalled;
photo is not as clear as it could be) Also "IDM board" is not present on
schematic on cover.

thanks

nate


Followup: looking at this diagram

http://www.alpinehomeair.com/view.cf...1-3B9839F377F0

it seems that I could just pull some thermostat wires from the furnace
control board and piggyback off the "W" and "C" terminals (I'm assuming
W is White e.g. heat and C is common) to only energize the humidistat
when the thermostat is calling for heat... yes? No problem with that
plan? (I could get rid of the sail switch and separate transformer if I
did it that way, too...)

Yeah, I don't really know what I'm doing, but I do know enough to see
that the way this installation that I'm messing with was done is kind of
Rube Goldbergian and also does not lock out the humidifier when the A/C
is on which is the main reason why I'm trying to redo it.

nate


--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On 10/23/2011 11:29 AM, Nate Nagel wrote:
....

... (I could get rid of the sail switch and separate transformer if I
did it that way, too...)

Assuming you replaced it w/ an appropriate humidstat, yes.

....

... does not lock out the humidifier when the A/C
is on which is the main reason why I'm trying to redo it.
....

Nothing but a comparative story follows, but--

Just discovered during a new furnace installation here the humidifier
had been wired that way for 30+ yrs. (I hadn't used it since we moved
back after dad died owing to a leak in the line and thinking were going
to replace anyway, never got the necessary round tuit until this year...)

I suppose Dad simply closed the supply valve in summer. BTW, old units
are not at all unlikely to not have the extra terminals on the control
and the 120V sail switch was also pretty much the standard back then;
same setup here. Also, the humidstat portion had failed so ended up
replacing it and solenoid w/ the low voltage ones and the new furnace
(Carrier) being new does have the terminal so all is well...

--

Nate Nagel wrote:
Given this wiring diagram

http://www.patriot-supply.com/files/...-22528-02).pdf


there's no connection for a humidifier, is there...?

My brain is working slowly this morning and I'm annoyed at having to
search all over the place for part nos. etc.

this is for a Rheem RGEB-06EC-FS furnace which apparently uses a
47-22481-81 fan control board. The "Honeywell S-890G" has been replaced
at some point with a S8910U. The schematic on the actual cover is
slightly different from the PDF and labels the blower control as a
"Honeywell ST780C" (or maybe 788? I took a photo of it and reinstalled;
photo is not as clear as it could be) Also "IDM board" is not present on
schematic on cover.

thanks

nate

Hi,
No big deal as long as you remember humidifier comes on when blower
runs and if humidistat calls for humidity.(so called AND logic)
And is depending on what type of humidifier.

Nat


Followup: looking at this diagram

http://www.alpinehomeair.com/view.cf...1-3B9839F377F0


it seems that I could just pull some thermostat wires from the furnace
control board and piggyback off the "W" and "C" terminals (I'm assuming
W is White e.g. heat and C is common) to only energize the humidistat
when the thermostat is calling for heat...

You mean energize water valve solenoid thru humidistat? Just hope
thermostat lead(W) has enough juice to do this. I used the 24V AC step
down tranny which came with the humidifier. I don't use ODP.

yes? No problem with that
plan? (I could get rid of the sail switch and separate transformer if I
did it that way, too...)

Yeah, I don't really know what I'm doing, but I do know enough to see
that the way this installation that I'm messing with was done is kind of
Rube Goldbergian and also does not lock out the humidifier when the A/C
is on which is the main reason why I'm trying to redo it.

nate

Could work, if the humidifier is 24 VAC. Like you say, the
humidifier is not desired during AC mode.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Nate Nagel" wrote in message
...


it seems that I could just pull some thermostat wires from
the furnace
control board and piggyback off the "W" and "C" terminals
(I'm assuming
W is White e.g. heat and C is common) to only energize the
humidistat
when the thermostat is calling for heat... yes? No problem
with that
plan? (I could get rid of the sail switch and separate
transformer if I
did it that way, too...)

Yeah, I don't really know what I'm doing, but I do know
enough to see
that the way this installation that I'm messing with was
done is kind of
Rube Goldbergian and also does not lock out the humidifier
when the A/C
is on which is the main reason why I'm trying to redo it.

nate


--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Ideally, HUM is powered when both heat and fan are
energized. In this case, might not make a lot of difference
if the hum runs a few more minutes, on warm up.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Tony Hwang" wrote in message
...

Hi,
No big deal as long as you remember humidifier comes on when
blower
runs and if humidistat calls for humidity.(so called AND
logic)
And is depending on what type of humidifier.

On Oct 23, 6:13*pm, "Stormin Mormon"
wrote:
Ideally, HUM is powered when both heat and fan are
energized. In this case, might not make a lot of difference
if the hum runs a few more minutes, on warm up.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Tony Hwang" wrote in message

...

Hi,
No big deal as long as you remember humidifier comes on when
blower
runs and if humidistat calls for humidity.(so called AND
logic)
And is depending on what type of humidifier.

humidifier is old and I'm having a hard time finding info on it too
but it appears to have a 24V humidistat but runs off 120V. As another
data point I actually got the sail switch working again - just had too
much stuff built up on the sail, was staying locked "on" all the
time. Cleaned and now works. I was thinking rewiring properly but in
the same configuration as it was before, but ditching the 24V xformer
(actually more like 28V) and pulling the low voltage power for the
humidistat from the W/C terminals of the thermostat, that way low
voltage is not energized unless thermostat is calling for heat, 120V
is not energized unless air is flowing in return. If the sail switch
happens to fail while I am still there I could just get a current
sensing relay for the fan motor and switch the low voltage through
that as well. My only concern is the added load on the heat contact
in the thermostat. Not sure how much humidifier draws @ 24V in
operation, nor what the thermostat contacts are rated for (and I can't
take measurements until I get this operational again, still need to
find what the correct water panel is for this unit.)

nate

On Oct 24, 8:08*am, N8N wrote:
On Oct 23, 6:13*pm, "Stormin Mormon"





wrote:
Ideally, HUM is powered when both heat and fan are
energized. In this case, might not make a lot of difference
if the hum runs a few more minutes, on warm up.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Tony Hwang" wrote in message

...

Hi,
No big deal as long as you remember humidifier comes on when
blower
runs and if humidistat calls for humidity.(so called AND
logic)
And is depending on what type of humidifier.

humidifier is old and I'm having a hard time finding info on it too
but it appears to have a 24V humidistat but runs off 120V. *As another
data point I actually got the sail switch working again - just had too
much stuff built up on the sail, was staying locked "on" all the
time. *Cleaned and now works. *I was thinking rewiring properly but in
the same configuration as it was before, but ditching the 24V xformer
(actually more like 28V) and pulling the low voltage power for the
humidistat from the W/C terminals of the thermostat, that way low
voltage is not energized unless thermostat is calling for heat, 120V
is not energized unless air is flowing in return. *If the sail switch
happens to fail while I am still there I could just get a current
sensing relay for the fan motor and switch the low voltage through
that as well. *My only concern is the added load on the heat contact
in the thermostat. *Not sure how much humidifier draws @ 24V in
operation, nor what the thermostat contacts are rated for (and I can't
take measurements until I get this operational again, still need to
find what the correct water panel is for this unit.)

nate

Another thought - I could keep the separate xfmr and put a MR-101
relay or similar on the W/C terminals if it turns out load is a
problem...

nate

On Oct 23, 3:19*pm, Tony Hwang wrote:
Nate Nagel wrote:
Given this wiring diagram

http://www.patriot-supply.com/files/...atic%20(90-225...

there's no connection for a humidifier, is there...?

My brain is working slowly this morning and I'm annoyed at having to
search all over the place for part nos. etc.

this is for a Rheem RGEB-06EC-FS furnace which apparently uses a
47-22481-81 fan control board. The "Honeywell S-890G" has been replaced
at some point with a S8910U. The schematic on the actual cover is
slightly different from the PDF and labels the blower control as a
"Honeywell ST780C" (or maybe 788? I took a photo of it and reinstalled;
photo is not as clear as it could be) Also "IDM board" is not present on
schematic on cover.

thanks

nate

Hi,
No big deal as long as you remember humidifier comes on when blower
runs and if humidistat calls for humidity.(so called AND logic)
And is depending on what type of humidifier.- Hide quoted text -

- Show quoted text -

Actually, wired the way he proposes, the humidifier will come
on as soon as the thermostat calls for heat, ie before it's even
ignited or the blower has started. I assume by blower we're
talking about the air handler, not the inducer.

I had my previous furnace done like that and it worked
perfectly. I think there is even some advantage to doing
it that way, as it cuts off the humidifier as soon as the call
for heat ends. The blower then runs another couple mins
giving it a little more time to take away some of the moisture
left in the media, instead of having it sit in the furnace plenum.

On Oct 24, 8:08*am, N8N wrote:
On Oct 23, 6:13*pm, "Stormin Mormon"





wrote:
Ideally, HUM is powered when both heat and fan are
energized. In this case, might not make a lot of difference
if the hum runs a few more minutes, on warm up.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Tony Hwang" wrote in message

...

Hi,
No big deal as long as you remember humidifier comes on when
blower
runs and if humidistat calls for humidity.(so called AND
logic)
And is depending on what type of humidifier.

humidifier is old and I'm having a hard time finding info on it too
but it appears to have a 24V humidistat but runs off 120V. *As another
data point I actually got the sail switch working again - just had too
much stuff built up on the sail, was staying locked "on" all the
time. *Cleaned and now works. *I was thinking rewiring properly but in
the same configuration as it was before, but ditching the 24V xformer
(actually more like 28V) and pulling the low voltage power for the
humidistat from the W/C terminals of the thermostat, that way low
voltage is not energized unless thermostat is calling for heat, 120V
is not energized unless air is flowing in return. *If the sail switch
happens to fail while I am still there I could just get a current
sensing relay for the fan motor and switch the low voltage through
that as well. *

Why do you need the sail switch at all? What's the difference
if it starts to run as soon as the thermostat calls for heat?
In 2 mins the blower is going to start, no big deal.



My only concern is the added load on the heat contact
in the thermostat. *Not sure how much humidifier draws @ 24V in
operation, nor what the thermostat contacts are rated for (and I can't
take measurements until I get this operational again, still need to
find what the correct water panel is for this unit.)

nate- Hide quoted text -

- Show quoted text -

Agree. I'd hook it up temporarily and measure how much
it draws. Some probably draw very little because they
just use it as a sensing circuit. Others power the water
solenoid and could draw a lot more.

On Oct 24, 9:45*am, "
wrote:
On Oct 24, 8:08*am, N8N wrote:





On Oct 23, 6:13*pm, "Stormin Mormon"

wrote:
Ideally, HUM is powered when both heat and fan are
energized. In this case, might not make a lot of difference
if the hum runs a few more minutes, on warm up.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Tony Hwang" wrote in message

...

Hi,
No big deal as long as you remember humidifier comes on when
blower
runs and if humidistat calls for humidity.(so called AND
logic)
And is depending on what type of humidifier.

humidifier is old and I'm having a hard time finding info on it too
but it appears to have a 24V humidistat but runs off 120V. *As another
data point I actually got the sail switch working again - just had too
much stuff built up on the sail, was staying locked "on" all the
time. *Cleaned and now works. *I was thinking rewiring properly but in
the same configuration as it was before, but ditching the 24V xformer
(actually more like 28V) and pulling the low voltage power for the
humidistat from the W/C terminals of the thermostat, that way low
voltage is not energized unless thermostat is calling for heat, 120V
is not energized unless air is flowing in return. *If the sail switch
happens to fail while I am still there I could just get a current
sensing relay for the fan motor and switch the low voltage through
that as well. *

Why do you need the sail switch at all? *What's the difference
if it starts to run as soon as the thermostat calls for heat?
In 2 mins the blower is going to start, no big deal.

My only concern is the added load on the heat contact

I'm worried about water overflowing if the humidifier really isn't
pumping the water into the unit. I tried it just to see if it worked
before (with an obviously disintegrating water panel) and it
overflowed after a few minutes (furnace wasn't running.) So I'd like
to lock it out when it's not actually going to be providing humidity.


in the thermostat. *Not sure how much humidifier draws @ 24V in
operation, nor what the thermostat contacts are rated for (and I can't
take measurements until I get this operational again, still need to
find what the correct water panel is for this unit.)

nate- Hide quoted text -

- Show quoted text -

Agree. *I'd hook it up temporarily and measure how much
it draws. *Some probably draw very little because they
just use it as a sensing circuit. *Others power the water
solenoid and could draw a lot more.- Hide quoted text -

I'm pretty sure that this one uses the 24VAC to drive the solenoid,
hence my concern.

n

On Oct 24, 9:41*am, "
wrote:
On Oct 23, 3:19*pm, Tony Hwang wrote:





Nate Nagel wrote:
Given this wiring diagram

http://www.patriot-supply.com/files/...atic%20(90-225....

there's no connection for a humidifier, is there...?

My brain is working slowly this morning and I'm annoyed at having to
search all over the place for part nos. etc.

this is for a Rheem RGEB-06EC-FS furnace which apparently uses a
47-22481-81 fan control board. The "Honeywell S-890G" has been replaced
at some point with a S8910U. The schematic on the actual cover is
slightly different from the PDF and labels the blower control as a
"Honeywell ST780C" (or maybe 788? I took a photo of it and reinstalled;
photo is not as clear as it could be) Also "IDM board" is not present on
schematic on cover.

thanks

nate

Hi,
No big deal as long as you remember humidifier comes on when blower
runs and if humidistat calls for humidity.(so called AND logic)
And is depending on what type of humidifier.- Hide quoted text -

- Show quoted text -

Actually, wired the way he proposes, the humidifier will come
on as soon as the thermostat calls for heat, ie before it's even
ignited or the blower has started. *I assume by blower we're
talking about the air handler, not the inducer.

Sorry, yes, I was referring to the big air handler blower, not the
inducer fan... I suppose it's possible to interlock it with that, but
I'm not sure why you'd want to.


I had my previous furnace done like that and it worked
perfectly. *I think there is even some advantage to doing
it that way, as it cuts off the humidifier as soon as the call
for heat ends. *The blower then runs another couple mins
giving it a little more time to take away some of the moisture
left in the media, instead of having it sit in the furnace plenum.

Actually if I got real fancy I could keep the humidifier blower
running after the water valve shuts off, but that might violate the
KISS principle

The real reason that I'm going through all this effort is that I had
to do similar work at my old house after one day I found that either
the A/C was running or the thermostat had been set to "Fan On" (I
don't remember which it was right now, but the heat was definitely not
on) and due to the A/C having been added much later than the
humidifier, no thought was given to interlocking everything so that
the humidifier wouldn't run when the A/C was running, only when there
was a heat call and the AH blower was running. So there was water
running straight through the humidifier and down the drain, which is
kind of wasteful and pointless. However, once I did my research, in
that case it was fairly easy as the humidifier was straight 120VAC and
the furnace control board had a 120VAC "HUM" terminal - for reasons I
don't understand, the receptacle for the humidifier was wired to a
120VAC terminal on the board that was given for an electrostatic air
filter instead of the "HUM" terminal (the air filter actually used a
DP switch to turn it on so that terminal was unused) in that case the
actual fix took about 1% of the time it took to figure it out. Once I
understood what was going on it was kind of a head smacker

SO... in the interest of getting this place set up so that everything
happens automagically, should someone set the thermostat to "auto,"
I'm trying to replicate that sequence but with different components...

nate

On 10/24/2011 8:45 AM, wrote:
....

Why do you need the sail switch at all? What's the difference
if it starts to run as soon as the thermostat calls for heat?
In 2 mins the blower is going to start, no big deal.
....

'Cuz it also is the humidstat/humidity control.

If you're in an area dry enough it doesn't matter, ok, otherwise it
might be too much at times.

--

On Oct 24, 11:44*am, dpb wrote:
On 10/24/2011 8:45 AM, wrote:
...

Why do you need the sail switch at all? *What's the difference
if it starts to run as soon as the thermostat calls for heat?
In 2 mins the blower is going to start, no big deal.

...

'Cuz it also is the humidstat/humidity control.

If you're in an area dry enough it doesn't matter, ok, otherwise it
might be too much at times.

There is a mechanical humidistat, but it seems to me that the flow
rate of the water is such that it might overpower the drain if the
water isn't actively evaporating off the panel. That's my main
concern. That, and the sail switch is already there and (now)
functional, so it doesn't cost me anything to leave it in the
circuit. Also, the issue that prompted me to immediately dig into
this was the furnace not lighting, so it's possible (although not
normal operation) that there might be a heat call but no actual air
handler activation, and in such a case you wouldn't want the
humidifier to operate.

nate

On 10/24/2011 7:08 AM, N8N wrote:
On Oct 23, 6:13 pm, "Stormin Mormon"
wrote:
Ideally, HUM is powered when both heat and fan are
energized. In this case, might not make a lot of difference
if the hum runs a few more minutes, on warm up.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

"Tony wrote in message

...

Hi,
No big deal as long as you remember humidifier comes on when
blower
runs and if humidistat calls for humidity.(so called AND
logic)
And is depending on what type of humidifier.

humidifier is old and I'm having a hard time finding info on it too
but it appears to have a 24V humidistat but runs off 120V. As another
data point I actually got the sail switch working again - just had too
much stuff built up on the sail, was staying locked "on" all the
time. Cleaned and now works. I was thinking rewiring properly but in
the same configuration as it was before, but ditching the 24V xformer
(actually more like 28V) and pulling the low voltage power for the
humidistat from the W/C terminals of the thermostat, that way low
voltage is not energized unless thermostat is calling for heat, 120V
is not energized unless air is flowing in return. If the sail switch
happens to fail while I am still there I could just get a current
sensing relay for the fan motor and switch the low voltage through
that as well. My only concern is the added load on the heat contact
in the thermostat. Not sure how much humidifier draws @ 24V in
operation, nor what the thermostat contacts are rated for (and I can't
take measurements until I get this operational again, still need to
find what the correct water panel is for this unit.)

nate

As you note the 24V water solenoid current may be an issue if you
connect the solenoid to W-C at the furnace. I think it is unlikely the
current is too high.

In the good old days the thermostat had a "heat anticipator" that caused
the stat to shut down heat a little early. The anticipator at the stat
was set to the gas valve current. The current would be higher if you add
the solenoid. This is probably not an issue with recent stats. The round
Honeywell T87s have an anticipator adjustment.

If the anticipator setting is a problem it is even more of a problem
when the water solenoid valve is switched on and off by the humidistat.
Connecting W-C to the coil of a control relay would eliminate that problem.

I used to replace the SPDT fan relay with a DPDT relay. There is a point
to connect a transformer for the humidifier where the humidifier is only
powered when the plenum gets hot and turns on the fan (like HUM in your
other post). (The circuit you posted has a SPDT fan relay.)

A sail switch control is OK. I would add a switch to shutdown the
humidifier in cooling season. I have a vague recollection that some
water solenoid valves were water cooled. You might check if the valve
gets a lot hotter if the water is turned off.

--
bud--

On 10/24/2011 11:20 AM, N8N wrote:
....

There is a mechanical humidistat, but it seems to me that the flow
rate of the water is such that it might overpower the drain if the
water isn't actively evaporating off the panel....

The solenoid should shut off the water when there's no demand...tied w/
the sail switch since you have one or from the HUM contact on a furnace
w/ that logic on the board.

Generally, the old Honeywell sail switches I'm familiar with were
dual-function humidistat/flow switch using a humidity-sensitive
lever-connection that stretched/shrunk as humidity went up/down that
controlled the contacts.

As noted, replaced both w/ the solid-state humidistat and the new
furnace has the HUM logic onboard so all is much simpler that way.

I thought you said you do have a solenoid; doesn't it shut the water off
when not demanded? If not, what _does_ it do?

--

On Oct 24, 4:12*pm, dpb wrote:
On 10/24/2011 11:20 AM, N8N wrote:
...

There is a mechanical humidistat, but it seems to me that the flow
rate of the water is such that it might overpower the drain if the
water isn't actively evaporating off the panel....

The solenoid should shut off the water when there's no demand...tied w/
the sail switch since you have one or from the HUM contact on a furnace
w/ that logic on the board.

Generally, the old Honeywell sail switches I'm familiar with were
dual-function humidistat/flow switch using a humidity-sensitive
lever-connection that stretched/shrunk as humidity went up/down that
controlled the contacts.

As noted, replaced both w/ the solid-state humidistat and the new
furnace has the HUM logic onboard so all is much simpler that way.

I thought you said you do have a solenoid; doesn't it shut the water off
when not demanded? *If not, what _does_ it do? *


Right, I wanted to interlock the valve to something other than *just*
the sail switch and humidistat - because all the sail switch does is
detect airflow (this one appears to be a simple sail switch) to
prevent the humidifier from running when someone manually turns on the
fan just to circulate air and/or the A/C is running.

I think after thinking this over I will go ahead and get a MR-101 or
similar relay unit to provide me a set of dry contacts that change
state on a heat call and leave everything else substantially the way
it was (re-running the 120V feed to the sail switch though so that it
a) doesn't lay on top of the supply plenum and b) will be cut off by
the furnace cut off switch, so that it doesn't require shutting off
the breaker for maintenance.) I suspect that the reason that this
wasn't done is that like my last house, the humidifier was installed
prior to the installation of central air and/or a thermostat with a
switch that could manually force the fan on without a call for heating
or cooling, so no thought was given to interlocking it (or in other
words, if air was flowing in the return plenum, it was a pretty safe
bet that the furnace was operating at that time.)

nate