Humidifiers and Dehumidifiers - Humidifier to run with fan
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ideburger
12-04-08, 11:39 AM
I have a 95% efficient Goodman furnace that is less than a year old. It has a Generalaire Model 81 drum humidifier installed on the cold air return. The humidifier drum turns when there is a call for heat. I would like to wire it so that the humidifier will work when I turn on the blower fan manually from the thermostat.
The humidifier is 24 volt and gets its power from the furnace without a transformer. One wire goes from the humidifer to the humidistat. Another from the humidisat to a pressure switch that supplies the 24 v during a call for heat. The other wire from the humidifier goes to the common terminal for thermostat connections in the bottom compartment of the furnace. I am pretty sure this is correct, but I am not looking at it at this moment.
Is there any way to supply the 24 V to the humidifier when the fan is on without a call for heat??? Thanks for any help.
The humidifier is 24 volt and gets its power from the furnace without a transformer. One wire goes from the humidifer to the humidistat. Another from the humidisat to a pressure switch that supplies the 24 v during a call for heat. The other wire from the humidifier goes to the common terminal for thermostat connections in the bottom compartment of the furnace. I am pretty sure this is correct, but I am not looking at it at this moment.
Is there any way to supply the 24 V to the humidifier when the fan is on without a call for heat??? Thanks for any help.
Jay11J
12-04-08, 08:18 PM
. It has a Generalaire Model 81 drum humidifier installed on the cold air return.
Wow, I didn't think anyone still use that style anymore.
What's the full model # of your furnace?
If your furnace has EAC on the board, then you will have to put a transformer on it to make it work.
Wow, I didn't think anyone still use that style anymore.
What's the full model # of your furnace?
If your furnace has EAC on the board, then you will have to put a transformer on it to make it work.
ideburger
12-05-08, 09:30 AM
The model # is GMH951155DXAC
I am thinking I can splice into the green wire (fan) from the thermostat and run it the the humidifier. This is the only place I can find 24 volts when the fan is on "always on" mode. If I hook that wire up with the existing wire on the humidifier that runs to the ID blower pressure switch, the pressure switch stays open and the furnace won't work when calling for heat. My plan is to put a switch on that wire that runs to the pressure switch. That way, I can switch it off if I want to run the humidifier on fan only and the furnace will operate as if the humidifier wasn't even there. When the fan is on "auto" I can turn the switch back on, and things will be back to how they were before I started any of this mess!
Does any of that make sense??? Are the Model 81's outdated? Thanks again for the help.
I am thinking I can splice into the green wire (fan) from the thermostat and run it the the humidifier. This is the only place I can find 24 volts when the fan is on "always on" mode. If I hook that wire up with the existing wire on the humidifier that runs to the ID blower pressure switch, the pressure switch stays open and the furnace won't work when calling for heat. My plan is to put a switch on that wire that runs to the pressure switch. That way, I can switch it off if I want to run the humidifier on fan only and the furnace will operate as if the humidifier wasn't even there. When the fan is on "auto" I can turn the switch back on, and things will be back to how they were before I started any of this mess!
Does any of that make sense??? Are the Model 81's outdated? Thanks again for the help.
Jay11J
12-06-08, 06:58 PM
I would not bother messing around with the switch, and the "What if?" things come into play then you are i more of a mess.
I would suggest to get a 24v transformer, and wire it on to the EAC on the board. The EAC will power up any time the blower is running in heat or fan on mode.
Are the Model 81's outdated?
Some what.. People don't use those cuz they are at risk of overflowing if the float fails, and also if the pan isn't clean it's a breading ground.
I would suggest to get a 24v transformer, and wire it on to the EAC on the board. The EAC will power up any time the blower is running in heat or fan on mode.
Are the Model 81's outdated?
Some what.. People don't use those cuz they are at risk of overflowing if the float fails, and also if the pan isn't clean it's a breading ground.
Jocko_johnson
12-07-08, 05:57 PM
On my Aprilaire 700 I was able to do this with a current sensing relay. May be an option but I am not a pro and have no idea about your unit It was a generalAir and only took about 10 minutes to add to the setup. I bought it new on Ebay for about $18.