Replacing Aprilaire model 600 humidifier


Old 01-14-15, 12:59 PM
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Replacing Aprilaire model 600 humidifier

Ok, this is my first time on this forum so bear with me. I am replacing an 10 year old aprilaire model 600 humidifier with a new model 600 and this is going on a Lennox G61MPV furnace. Despite being the same model, they have under gone some revisions in the last 10 years.

The wiring has changed, and the terminals have changed. I have everything else hooked up. I just used to old valve and piping because it still has good flow. I used the same hole for the humidifier as they are the same size. Incidentally it is located on the return plenum I assume thats ok. The model 60 controller mounts differently now and I had to make a new hole upstream for it.

To the wiring. This is my set up, I had to add a few thing to it, and I wanted to get some feedback before I turned the power back on. The old controller had no W terminal, just R,C,H,H, and I,I. The new one has a W.
Here is what it looks like:

Furnace---------------Model 60 humidistat

Now the old controller had no extra transformer but this one does. My furnace control board which looks like this:
has a HUM spade terminal, but no HUM neutral. So I just ran a wire from the HUM spade to the Black live on the transformer, and a wire from on of the extra neutrals to the white neutral on the transformer. Then ran one of the solenoids wires to the 24V side of the transformer and the other side of the transformer to the one of the H terminals on the humidistat. The other H went right to the solenoid. it looks like this:
120V side 24V side

Hum---------------------Black 24VT1----------H1 H2---------------W1
Generic Neutral--------White 24VT2--------------------------------------W2

T1= terminal 1 24V side
T2= Terminal 2 24V side
W1= wire 1 solenoid
W2= wire 2 solenoid
H1,H2= H terminals on humidistat.

Please let me know if this looks okay, and please ask me to clarify anything I did not explain well enough. I don't want to turn the power back on until I am sure nothing will fry. Thanks.
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Old 01-15-15, 12:20 AM
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Welcome to the forums.

You can either wire the transformer always live or use the HUM and NEUT terminals.
Your wiring looks ok.

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