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condensing furnace inducer fans - designed to get wet?

mik2 Member Posts: 4
edited October 2020 in THE MAIN WALL
Can someone explain to me how an inducer fan works in a condensing furnace?

I cant wrap my head around it, it seems wrong the water is always flowing back towards it.

How come the fan doesnt push water in the same direction as the exhaust?
Doesnt water flowing backwards towards the drain just fall into the fan housing in addition to the boot at the top where it redirects the water to the drain/collector box?
I know the motors are mounted to the outside of the housing. Does that mean the interior of the housing is supposed to be a wet location?
How is the water redirected then once it reaches the coupling? And how might it overflow into the fan?

Lots of questions for sure, I hope maybe someone could explain a bit for me.

I ask because since my furnace was new I have at times heard the sound of water droplets in the exhaust when the unit first fires. I dont know if its water hitting the sides of the pipes I am hearing or maybe water droplets actually coming in contact with the fan blades. My vents and drains are slopped properly but its always concerned me. Is it normal it hear water in the exhaust vents at times?


    JUGHNE Member Posts: 11,021
    edited October 2020
    First of all the exhaust piping is sloped to drain the condensate water back to the furnace. If it sloped to drain to the exhaust opening then the water would drip outside down your wall, (assuming side wall venting) and eventually the exhaust opening would freeze shut in the winter.

    There are several methods to drain the water at the furnace without it getting into the fan. Some use a tee drain on the side of the furnace to collect the most of it. The rubber coupling may have drain ports on it to collect the remaining.
    The outlet of the fan is often a concentric fitting with the smaller port actually doing the exhausting of gases the the larger ring being a water collection point.
    Water will trickle down a pipe clinging to the inside surface and then be collected by the concentric fitting.

    Locate the install manual for your furnace, it should be with the furnace or you can download one.....it may be 60-70 pages long.

    The venting instructions will give a variety of install options.
    Some to vent left.....vent right....furnace horizontally left...right...etc.
    Each option will have different configurations of condensate drains. Each drain port used must be trapped....but only once.
    It is possible that one hose was not connected to the proper port.

    Also the furnace must be sitting level for the drainage to work properly.
  • mik2
    mik2 Member Posts: 4
    Thank you for mentioning the concentric drain... i did not consider that.
    JUGHNE Member Posts: 11,021
    What brand and model of the furnace is this?
    Did you find the manual for install?

    You can post pictures, with the door off and include the drain piping.
    HVACNUT Member Posts: 5,738
    A drain is clogged somewhere. 
  • icy78
    icy78 Member Posts: 404
    If you have a double 90 in the venting, (a no-no) you'll hear water at times.