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Steam Injection Humidifier

What Is The Best Way To Install And Service?

aThe canister type and steam cylinder type are the most commonly used steam humidifiers.
The essential part of this humidifier is the canister with electrodes inside, where the steam is made.

On a call for humidity,  there is a current which flows through the water between the electrodes. Conductance and resistance are provided by the minerals for electric flow, and steam is made.
After that  the steam rises out of the canister. Then the steam is distributed through a steam hose into the forced air ductwork for distribution. It can also be distributed to a through-wall fan pack for direct room distribution.


Essential Information About To Ponder About Steam Humidifiers:

  • If radiant is your main heating source for your residency, the steam humidifier is the best  device to humidify your home. An evaporative type (bypass or powered flow-through) does not work well without a heated air stream for delivery.

Installation Of The Canister Type Steam Humidifier:

  • Take the front cover away, take the steam cylinder away.
  • Place the humidifier.  The best location for the unit is close to the ductwork or the remote fan unit as possible to make condensate minimal. Place the unit on a wall. Do not assemble the unit on any vibrating surface, such as the air handler or ductwork.
  • sPlace, cut in, and fit the steam distribution nozzle into the ductwork above the humidifier whenever possible, or locate the position of the remote through-wall fan unit.
  • Place the steam hose. The steam hose should have a slope. Twists and low places should be avoided. They can trap condensate and cause future problems.
  • Place the nozzle into drain hose. This small hose  drains back to the humidifier. Insure you have a slope and you trap the hose as every producer recommends.
  • Follow the manual.  You have to keep clearances for easy maintenance access.
  • Fasten water feed.  You have to place a 1/4″ water line hook up at the unit.  You can use self piercing saddle valves , or replace them with a standard 1/2″ ball valve, and run a 1/2” water line to within 3 feet before reducing to 1/4” OD for the final connection.


Potable water should be used. Water conductivity should be between 125 and 1250 micromhos. If water conductivity go beyond 250 micromhos,  softened water should not be used. The  water without minerals should never be used, because there are no minerals to conduct the electricity.

Fasten water drain.  It is necessary to trap the drain line when it exits the unit to avoid the situations when steam  rises out of the drain pipe and condenses inside the humidifier unit. Some steam humidifiers need a large 1 1/2” O.D. plastic drain pipe. Others need only a 1″ or a 3/4″ CPVC drain line. Follow your installation manuals.


Drain water can be up to 200°F, hence the use of CPVC instead of standard PVC piping.

  • Fasten together Power Wiring. Follow the producer’s recommended wiring schematics closely. Every brand of steam humidifier has its own unique characteristics and requirement.

You can  wire ‘ Nortec’ and ‘ResDelux’  with 120 volt or 240 volt. The humidity output will be affected by that.  A common and a ground lead for the 240 volt unit are required for ‘Nortec’.

A ‘GeneralAire’ unit requires 240 volt high voltage wiring.

  • Connect low voltage wiring. The typical steam humidifier control wiring system usually has a wall or return humidistat, a high limit duct humidistat, and an air proving switch. (read the producer’s tips).

Location of these controls are vital for proper operation of the system.

If you use an  airflow switch, you have to position it to open on a loss of air flow, you have to prevent the humidifier from running when there is no air to absorb the moisture.

Other Types

We have told about the canister (cylinder) type steam humidifiers here. The types and brands we have described are certainly not the only brands  on the market! The Honeywell “TrueSteam” described and shown  above does not have a canister inside. The Aprilaire 1160 pictured on our main humidification page does not have it either. The Honeywell “TrueSteam” may also be placed on the ducting (unlike most steam humidifiers). It may also be placed far from the hose and nozzle kit.