I just purchased a new humidifier (attaches to the furnace). Do I wire
it from the blower and if so, how do I know what wires to attach from
the blower to the humidifier? It's a mess of wires in there!
I wired it from the switch straight to the humidifier. It works but
continuously flows water. I assume this needs to be wired to the
blower but I want to be sure I wire it correctly.
I do not think it gets wired to the blower simply because if you just
turn your fan on at the thermostat, the humidifier will constantly be
On my furnace, the humidifier kicks on only when the heat is on, but
once the heat has been satisfied and the gas burner kicks off, the
humidifier also goes off, even if the fan stays on. I do not think the
humidifier will do it's job correctly if just the fan is on and no heat
passing through it.
On my Trane XR 80 furnace, the humidifier is hooked up to the C and Y
terminals on the board. This is not to say you furnace is similiar,
but just to give you a reference.
What does the instructions say that came with the humidifier when you
Part of my problem is that the installation instructions that came with
the humidifier are extremely vague. They don't tell me anything.
I bought a Honeywell Humidifier, and for $70 more, I could have
purchased the installation kit to go with it. I didn't need any more
parts except the installation kit comes with a video tape installation
I couldn't justify spending the $$ for a video tape.
Anyway, since I have it wired directly from the power source to the
transformer to the humidifier, the humidifier will run all the time,
whether the furnace is on or off. That is why I thought the wiring
needed to be changed but I am still confused.
You sure the install kit didn't include a current sensing relay, or a
How a specific unit should be wired will vary. But in general, there
are several options:
1 - Wired direct to go on when the blower turns on
2 - Wired direct to go on when the burner is on
3 - Wired using a current sensing relay to go on either with the blower
4 - Wired with a sail switch to go on with the blower.
Whic option is best depends on the furnace, the humidifier, and how
easy/hard any of these options is for that particular install.
"Isn't there some sort of controller which mounts in the living area
to sense humidity? "
Most have a humidistat that mounts on the return air plenum. But that
doesn't solve the problem of having the unit only turn on when the
furnace and/or blower are running. The humidistat is just another
on/off that will only turn it on when the humidity in the return air is
below the set point.
I have determined that this will need to be wired to either the blower
or the burner. Since I am new to this, I am assuming this can be done?
What it is doing now is when the furnace is on or off, the water
continues to flow through the pad into the drain hose, non stop.
Can anyone easily explain how to wire this up?
By the way, there was an existing humidifer on the furnace but I made a
mistake and forgot to label how it was installed when I removed it.
You need to know what voltage it needs (generally 12 - 24 or 120V) and
what amperage it needs, then you need to find a switched source with
sufficient excess capacity for it or use a relay to reduce the load.
The more I think about it, the more I think you should junk this thing
and buy a good humidifier like Aprilair.
I see you are back spreading misinformation again Mr. Meehan. he
already got the proper advice but you are of course wrong again!!
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Check out the Aprilaire 600. It has a control that mounts on the furnace.
The more expensive Aprilaire 700 ( I believe it is) has a unit that mounts
by the upstairs thermostat. I don't mind going down stairs to my furnace to
adjust it. I just set to around 45% and forget it till Summer.
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