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Replacement For Steam Humidifier On High Velocity Mini Duct System

PGB1 Member Posts: 49
Hello All!
In our home, we heat hydronically. For summer cooling we have a Hi-Velocity HV-70BU by Energy Saving Products, LTD. It is a mini duct system, similar to the Unico.

For humidity, we have a White Rodgers HSP2600 (Same as the more familiar Skuttle Model 60). It is mounted on the return plenum of the horizontally mounted HV-70 BU air handler, just past the filter but before the evaporator, blower and UV light.

When the humidistat calls for humidity, the HV-70BU's fan goes to high (cooling mode) speed. Upon satisfying the fan proof ammeter, it allows the water in the humidifier's tank to heat. The steam rises into the plenum and is drawn through the blower and pushed into the ductwork. Upon satisfied humidistat, the heating element turns off and the fan continues until the water cools to 160 Degrees-F.

The challenges we face are that this unit is a maintenance nightmare and it is costly to operate. It has to be removed and de-limed monthly, despite a water filter and a de-ioinizing filter. Oddly, we have Detroit city water and it isn't terribly lime filled. The components of the unit also fail frequently and are costly to replace. Of course, a 2,000 watt heating element is expensive to run at 20 cents/Kwh.

But, I think today's problem has made me decide that the unit has to go.
I drained it for routine de-liming and found that the float was stuck in the "OK" position. This would allow the elements to heat when the pan is empty, such as when the fill valve is limed closed. That is scary.

When I first wanted a humidifier, I was told by several people that we have to use steam because the air in the air handler is cool, therefore a drum type or pad type humidifier would not work. This makes sense to uneducated me.
There were steam generator types on the market, but they were very expensive. Today, I can't find any on line.

I've been looking at atomizing humidifiers, such as Trion CB777. I also looked at some generic misting humidifiers that are used in hydroponics. (The hydroponic types would require some adapting to use in ducts.)

I am wondering if the cool mist produced by these will be carried to the house through the room temperature air ducts.
Also, would it be better to move the unit to the discharge side of the air handler, thus not pushing damp air through the blower and evaporator. (I recently had to de-rust and galvanize the blower wheel and housing. I assume the rust is from the steam.)

Does a cold mist system sound like it would work? Do any of you have a humidifier to recommend for our set up?

Thanks Very Much for helping me decide what to do about whole house humidification.

Enjoy Today!


  • Tinman
    Tinman Member Posts: 2,804
    I've installed and serviced a lot high velocity systems and I've never added a duct mounted humidifier to them.

    My suggestion is to get a stand alone central humidifier like an Aprilaire 350.

    Steve Minnich
  • PGB1
    PGB1 Member Posts: 49
    Thank You Steve for your suggestion.
    The Model 350 looks interesting and like a probable solution. It certainly will cost less to operate and maintain.

    The steam humidifier is pretty much frustrating me today. I de-limed it and a tank seam started leaking. I can't count how many times I've TIG welded leaks in the tank over the years. Either we have evil water, or the stainless steel isn't so stainless. (Maybe it is 410?)

    Next, I pulled the fill valve arm out of the vinegar it was soaking in. How about that! The arm rotted off the valve head. Guess the lime was holding it together. There wasn't enough copper to braze back together. Comical, but frustrating. There's $25.00 out the window. Oh Well, such is life.

    This steam unit humidifies well, but the constant repairs & maintenance are a bit too tedious for me. (Guess I'm getting impatient in my old age.)

    So I certainly will investigate the Model 350 you mentioned. I not only look forward to a much simpler unit to maintain, but a lower energy bill too.

    Thanks Again Steve!
  • John Mills_5
    John Mills_5 Member Posts: 946
    Check out the Aprilaire 800. Can hook to the HV system or stand alone with a head that puts the steam in the conditioned space.
  • SuperTech
    SuperTech Member Posts: 1,919
    I wouldn't use any other unit than the Aprilaire 800. The only thing you have to do for maintenance is replace the steam canister yearly. Comparison between that and what you have now is like comparing a corvette to a Yugo. And pipe it into the plenum, no need to abuse your air handler like that.
  • MikeT_Swampeast_MO
    MikeT_Swampeast_MO Member Posts: 27
    Frankly I've never encountered any residential add-on humidifier to any sort of central system that works reliably with reasonable maintenance, reasonable operating cost and no property damage.

    Get a stand-alone humidifier. Humidity tends to equalize nicely and presuming yours is a multi-floor home of reasonable size with an open staircase just put it in a stairhall (ground floor best).
  • SuperTech
    SuperTech Member Posts: 1,919
    > @MikeT_Swampeast_MO said:
    > Frankly I've never encountered any residential add-on humidifier to any sort of central system that works reliably with reasonable maintenance, reasonable operating cost and no property damage.

    The Aprilaire 800 is nice. I can't speak for operating costs but reliability and ease of service is there. After years of dealing with the Honeywell True Steam nightmare I'm happy to say I have had no issues with the 800.
  • PGB1
    PGB1 Member Posts: 49
    Thanks All for the comments & suggestions!

    We're almost at the end of humidifying season here, so that gives us time to investigate all of the options and pick a solution.

    Right now, after just paying the electric bill, I'm leaning toward the Model 350 that Steve mentioned. (No heating element) But there are many factors to consider.

    Thanks Again & know that your suggestions and comments are much appreciated!

  • PGB1
    PGB1 Member Posts: 49
    Thanks Liffet88 for taking time to as this note. I appreciate your suggestion.