Humidifiers and Dehumidifiers - He-260 Mounting Question

I am looking at installing the he-260 and have a question about mounting it. I want to mount it on my return, but only have access to the side of the return. This is 10 inches wide. I read that the specs for the hole in the ductwork is 9 3/4". Will there be enough room here to mount the unit? If not, I will have to try and figure out how to get it on the supply side. Also, when mounting it on the return, the damper in the duct is just before it eneters the supply side. Isn't it better to block it before it gets out of the return? Not sure of the dynamics of the air flow.

I want to mount it on my return, but only have access to the side of the return. This is 10 inches wide. I read that the specs for the hole in the ductwork is 9 3/4". Will there be enough room here to mount the unit?
Yes you will have room to mount this.. The screws are going to be in the opening size.

Also, when mounting it on the return, the damper in the duct is just before it eneters the supply side. Isn't it better to block it before it gets out of the return? Not sure of the dynamics of the air flow.don't matter where you put the damper.. Just as long it can open and close as needed..

The air flow is going to come from the supply side, into the humidifier, over the pad, and into the return duct.

Thanks Jay. I picked up the unit on the way home and am getting everything ready to go. The furnace it is going on is about 15 years old. It is a Heil 5000. Looking at the wiring directions, it looks like I'll just have to use the transformer. I see some blue wires to 24V and 24V Gr, but it doesn't look like it has Humidifier connections.

Yeah, that old of unit, you will need to use the transfromer, and sail switch/A50 relay.

In searching the forum, I see where the unit can be wiired to an exaust pressure switch and the other side to the C terminal on the Thermostat connection board. Does that sound right? I'm pretty sure I saw the pressure switch last night. When I get home, I'll measure the voltages. Past posts had good info and great pictures.

YOu can try that, and hopefully the transformer on the furnace itself is big enough the handle the extra load.

Now you have me worried that I'll burn something up and break the furnace. Will I burn out the transformer by trying this?

IF the transformer is not big enough, the valve may clatter or won't open.

When I got home I measured the voltages at various spots. The pressure switch has 24v. The problem there I think is that while the ignitor is sparking, it shoots up to 80v. That will probobly wreck the he260, woudln't you think?. There is a terminal labled "valve" I could tie down on. I am pretty sure this opens the gas valve. It only has 24v while the gas is flowing, and 0 when it shuts down, even tho the fan keeps blowing. Do you think this would be ok? I didn't see any other place that had 24 only while running. I suppose I could tie into the actually leads to the fan, but I kind of only wanted it running when the heat was on. If you think this is unsafe or I might break something, let me know. I plan on installing this tomorrow and if I have to, I'll run out and get an A50. I'd rather use that than the sail switch, but I would rather use neither if I can.

Id go with the A 50 then its on when the blower is running. Not when just the gas valve is on.

No, I want it on when just the heat is on, not when just the fan is running. Wiring it to the gas valve lead does this as the gas doesn't open until the thermostat calls for heat. Would there be a problem wiring it to that point, safty or operational wise.

I would rather you use the A50 or Sailswitch.. Chances are you are not going to find the A50 at a store.. Put the A50 on the heating speed wire, and that will come on in heat, not cooling.

YOu could go on the gas valve 24 volts, but I'd rather not mess with the wire on the gas valve itself.

No, the gas valve is in the top cabinet and the wire runs down to the board and stuff in the bottom cabinet. Where I would connect it is completely isolated from where the gas valve actually is. It has a nice steady voltage. Comes in at the right time and stops at the right time. I might try it and see if it works. In the mean time, I'll try and find an A50. Would the hvac repair companies carry these, or should I just find one online? One other thing, which wire is the heating speed wire? Thanks for all your help on this. I remember installing a Sears humidifier at my old house. It was one of those that had the drum that turns and gets all gunked up. You just connected it to the furnace power and somehow it worked. Not very well, but it was better than nothing.

Depends on what speed the blower is set up in heating.. Take a look at the control board, and see if there a tap saying "HEAT", and should be a wire on that, and follow that to the blower motor.

Give a try with out the relays, and if it works out, then should be ok.

The flow though unit is going to use more water than the old drum style, but won't get the big gunk, and pool of stale water.

Just a quick post to let you know I got the unit in and it works just great off of the valve terminal and the common. Took me about 4 hrs from start to finish. Hardest part was cutting the square hole for the unit. Had to cut right up to the edge of the duct on both sides and one side had the double edge where they were fastened. I never have trouble with the round holes, but the square ones are always a bear. This made it a bit harder.

Again, thanks for your help.

Glad to hear you got it in... but Yikes! 4 hours.. Took me 45 min to do mine!