Looks like my humidistat calls for coil fan and for furnace heat
I have an Aprilaire 560 and recently it started to give me headaches. I think that the humidifier should work only when the coil fan is on…and that should happen only when the thermostat calls for heat on this zone. The fan is on “AUTO” and is controlled by the thermostat not by the furnace. If I change settings on my humidistat dial while the coil fan is off, I hear the “click” and the fan is starting instantly…after a while the furnace goes too and the temperature goes beyond the thermostat program. If I lower the humidity level just under the typical “click”, the furnace and the fan stops.
The only way to get some humidity without reaching 78F is to let the fan on “ON” instead of “AUTO” and to raise the level on my humidistat…this way the furnace follows the thermostat program set for 73F.
Re: Looks like my humidistat calls for coil fan and for...
It sounds like the humidifier may be improperly wired.
It's hard to solve without checking the wiring, but it seems like the humidistat is wired so that as the dial is advanced, it incorrectly turns on the fan, or furnace, or both. The contacts of the humidistat should be wired so that they turn on the solenoid only. Also, the power to the humidistat, to turn on the solenoid, should come on only when the fan is on.
Hope this helps!
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It sounds like it is just miswired. The low voltage wiring off the humidistat should be on W and C on the circ. board at the furnace. If you have it on R and C then it will power it constantly regardless if the heat is running or not. W is only energized on a call for heat which is typically when you want that type of humidifier to run
Depending on the age of your furnace you may have an aux terminal for a humidifier. If not, you should use the white wire (heat) coming from the homes thermostat to power up the humidistat and ultimately bring on the humidifier. This way it will only run when in heating mode.
Humidifier should be powered from the furnace heating 24 volt terminals through a humidistat and then to your humidifier. The fan and the water solenoid on the unit should come on together. if the water is not turned on the fan should still run, unless the unit is not plugged in.
That will work, The HUM feeds power to the humidifier when the fan is operating even in cooling on most models, However the humidistat must also be calling for humidity and probally won't call during the cooling months
It is possible you may have wired it wrong. Make sure your humidifer is not robbing power from your thermostat. This would explain when your humidifer makes a demand to come on it robs power from your t-stat making it lose its call for heat. Wire your humidistat to the "w" terminal and the common terminal so it only runs on a call for heat. With the bypass type of humidifier you purchased it wont do you any good to run when the heat isn't running anyway. If you want an independent operation humidifier you need a steam type.
I called the service company that put in my new furnace (FAmily Heating and Cooling in Detroit, very highly recommend these people)
Anyway they sent out a second service tech who determined that I would be better off having the humidifier wired to go on whenever the furnace fan was running instead of using the humidifier signal from the circuit board on the furnace. After he changed the wiring the unit runs fine. It is pretty likely that the circuit board was bad also.
Was having a similar problem. Disconnected the source line and opened saddle valve. I was getting water to the solenoid but nothing out the other side. My humidistat doesn't have a "test" setting, it's either off or the highest humidity. I held the outbound line in my hand and experimented with adjusting both sadlle valve and humidistat. I didn't get any water until I opened the saddle valve MUCH further than I thought was necessary and turned the humidistat to near the highest setting. Once I had water coming though I experimented with the setting on the humidistat, turning it off and then slowly increasing the humidity until the solenoid clunked and water started coming out. I would recommend anyone having this same problem to open the saddle valve all the way (I was surprised how many turns that took) and set the humiditstat to it's highest setting.