Need some help wiring 700M to goodman GMSS92. I was going to wire it like so
AprilAire Relay 50 - white wire from blower to relay metal bracket, one line from relay to C on the board, the other line to humidifier solenoid
Humidistat - one lead to front facing pressure switch , one lead to solenoid on humidifier
The front facing switch connection is circled on the image, is that correct place to wire humidistat?
Last edited by strel1337; 12-06-22 at 05:04 PM.
Reason: uploading smaller image
Here are the pictures of the board, are the connections e18 and e17? There are no connections that I see where HUM-H is labeled. I also didn't see any connections on the switch. I see com, NO/NC ?
I bought 700M fairly recently, so I would say it is new
EAC-H = electronic air cleaner and is a 120v terminal that becomes live when the blower runs.
HUM-H = humidifier and is a 120v terminal that becomes live when the burner operates.
There are no terminals there. That means there is no high voltage EAC or H terminals.
That should mean there are 24v contacts.
Post the part number off that board.
so do I just connect humidistat to yellow connector and solenoid on humidifier. And then run a wire from yellow connector to another line on humidifier to complete the loop?
After scouring the interwebs, looks like the wiring needs to be like so:
humidistat - connect one wire to pressure switch yellow wire, connect the other wire to solenoid on humidifier
c terminal on board - connect wire from C terminal to other solenoid wire PJmax let me know if I have it wrong or right, thank you for help!
I inherited a home last year (same furnace; AprilAire 500 series) and found that the humidifier was running 24/7 when the thermostat was adjusted to be on. I turned it off and then tried to figure out the issue. After reading a number of posts here and elsewhere I made a change tonight but not sure if there is a better solution.
Per the photos above there is no HUM terminal to attach a lead to per se.
The original wires were attached to R and C.
I found in a youtube video that W is heat on when the thermostat calls for it.
I tested the voltage from R & C - 24vac; enabled heat and W & C - 24v; disabled heat W & C 0v
I then migrated the R humidifier wire to W and now it is running only when the heat goes on
In my prior home I had a better unit (Honeywell) that I believe turned the humidifier on only when the blower started and then off when the blower went off (and I believe you could control that start delay). That would be a better method than just heat - since the initial few minutes is IMO not efficient. I am not used to these small economy PCBs with practically no adjustments (AFAIK) v. something with adjustments to every aspect by moving wires to another point.
So ideally I want either (A) to run the humidifier when the blower starts just after the heat goes on; or (B) as it is now - when the furnace starts in heat mode.
Reading through this thread specifically I am seeing the C and HUM in post #8 - yet again I see no HUM option on this board. Further @Pjmax mentioned
Connecting to the yellow wire on the pressure switch is verified.
Is the pressure switch related to the blower fan? I am missing what this means and the connection to make. Is there a screw connection? Assume the other side would remain as C.
(if there is a link to another post that explains it - please provide - thanks)
Yes... the Honeywell units powered on by air pressure from the blower.
A good system once you got it working but a bit of a nuisance.
If you use W the humidifier will start on a call for heat.
There isn't as much waste using the W terminal as you'd think.
For the humidifier to work with the burner/blower you need to locate HUM connections.
If you have the same exact board..... there is no HUM or EAC connection on that board.
You can connect your humidifier to the C terminal on the the terminal strip connector and to the yellow wire connecting to the pressure switch as shown in the circle in the first picture.
Thanks Pete - Sounds like the W option may be sufficient - working well thus far.
If I were to follow the yellow wire solution, that implies a SPLICING of the yellow below - and connecting the other side of the humidifier to it? I'd go back a bit - cut, strip and then join the existing and humidifer via marrette or similar. Yes? Thanks.
At one time there was an additional short piece of wire attached to the yellow for easy connection. It appears that is no longer done. You can carefully splice and insulate anywhere in the yellow wire.
I have a similar issue with my Aprilaire 600, and have tried the above wiring, but still cannot get the solenoid going. Here is how it' wired up:
R an C are connected to a 24v transformer on the side of the furnace, which is connected to the power supply 'before' the furnace control.
W is connected to W on the furnace.
I have the R on the humidistat connected to the Solenoid as well.
A jumper from the C to the 'left H on the humidistat, and the 'right' H connected to the other solenoid wire.
There is also a 'Com 24v' terminal on the furnace board. That red wire was previously connected to the 'Cf' on the old 58 Humidistat. now not connected to anything.
W was previously connected to the 'W/G' on the 58.
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TLDR - is there a way to make my humidifier blower unit work manually - while the humidistat is non-functioning/no power
I realize this is probably a dumb question - but our humidistat is broken. The HVAC guy was out to do an annual furnace check weeks ago, and said a ladybug had gotten inside at some point and shorted something out that made the humidistat not work. It is just a blank screen, no lights. He then unplugged the blower unit while we wait on the part to come in and have him come back. I wasn't home at the time, I am the handy person in the house and likely could have had it fixed by now. With the current weather situation and the furnace running more than normal, our house has become very dry. Is there a way for me to jump a wire or remove a wire somewhere so that I can plug the unit in and get the blower area to function without the humidistat? I know it would then run continuously, but I would set the fan portion of our furnace to 'on' for an hour or so and then unplug it - if that would help. I could easily do this a few times a day until he comes back.
12-06-22, 05:01 PM
