Trane Truesteam humidifier install and placement of spray nozzle?

[jmcomp]

Hi,
Our HVAC system has a heat pump + variable speed fan gas furnace and there is a A-coil in the supply.
I am having a humidifier (Trane truesteam) installed and there is no space below the A-coil for the outlet from the humidifier that sprays in the warm mist (spray pipe). According to the manual it has to be below the coil. There is space above the A-coil for the spray pipe. The installer is going to put that pipe above the coil which is not according the manual. No where in the manual it says that the spray pipe cannot be above the coil.
In a way it makes sense to have it above the coil, so if it condenses, the catch pan below the coil would catch the condensation and drain it. Is there any downside to having the humidifier outlet pipe above the A-coil?
Thanks!

[TalkingHead]

I think you can put the nozzle downstream of the coil with only one concern. The nozzle needs to be located in a spot where there is not enough back pressure from the fan blowing into the plenum to stop the steam from coming out. Make sure the air is moving past the nozzle with no potential for back pressure. Somewhere in the manuaul it says that the steam can not get out with a back pressure of over 0.5" w.c.

[jmcomp]

I think you can put the nozzle downstream of the coil with only one concern. The nozzle needs to be located in a spot where there is not enough back pressure from the fan blowing into the plenum to stop the steam from coming out. Make sure the air is moving past the nozzle with no potential for back pressure. Somewhere in the manuaul it says that the steam can not get out with a back pressure of over 0.5" w.c.

The nozzle is located above the coil (upstream) in the supply. Is this still a concern?
Thanks.

[D-Allen]

Is this a 2stage system?

[dunkman]

The manual actually says to put it below the coil? Is it an upflow system? We always put them above the A-coil, that's where you should see the least amount of static pressure.

[D-Allen]

I realize your delima and from what you describe this is a downflow furnace.and there is no access to ductwork under the coil. I would suggest installing the outlet pipe above the coil and if there is a problem with static pressure the humidifier can be controlled to operate only at lower CFM.