Questions and Answers
What is relative humidity?
What does an atomizing humidifier do?
Projects small water droplets into air either by mechanically flinging water or by forcing water through a nozzle.
What happens when humidity is too high in a building?
Growth of mold, bacteria, and fungus, formation of condensation on cold surfaces, swelling of hygroscopic materials.
What is the purpose of a float switch in a humidifier?
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When a humidifier adds moisture to air already heated by a furnace, then the temperature of the air _____
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The Air Changes Per Hour (ACH) refers to replacing the entire volume of air in one hour.
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Which humidity range is considered comfortable for humans?
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What type of humidifier uses its own heat source to create steam?
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A humidifier's water feed line should be tapped into a building's _____
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What is a desiccant?
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What is the function of a frost control element?
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A portable humidifier is best for humidifying an entire building.
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What is demineralized water?
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Dehumidifiers remove moisture from the air by maintaining a coil _____ of the air.
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What does the term 'soft water' refer to?
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Study Notes
Humidity and Humidifiers
- Relative Humidity: Ratio of moisture in the air compared to the maximum it can hold at the current temperature.
- Atomizing Humidifier: Projects small water droplets into the air using mechanical methods or nozzles.
- Evaporative Humidifier: Adds moisture through evaporation.
- Bypass Humidifier: Installed between supply and return plenums in central heating systems.
- Frost Control Element: Prevents airflow blockage by shutting off the compressor.
Effects of High Humidity
- Growth of mold, bacteria, and fungus can occur.
- Condensation forms on cold surfaces.
- Hygroscopic materials can swell due to excess moisture.
Humidity Control Devices
- Humidistat: Control device that responds to humidity levels.
- Float Switch: Shuts off the compressor to prevent condensation overflow.
- Desiccants: Chemicals used to absorb moisture from conditioned air.
Humidifier Operation
- When a humidifier adds moisture to pre-heated air, the temperature decreases slightly.
- Air Changes Per Hour (ACH) describes the complete air volume replacement in one hour.
- A solenoid valve in a humidifier operates when the furnace and blower are running.
Types of Humidifiers
- Vaporizing Humidifier: Uses its own heat source to create steam.
- Impeller Humidifier: Utilizes a spinning disk to fling water against a diffuser for atomization.
- Nozzle-Type Humidifier: Forces water through an orifice to produce a fine mist.
- Plate Humidifiers: Designed for low-capacity applications only.
- Rotating Disk Humidifier: Features spinning disks with shallow grooves to atomize water.
- Rotating Drum Humidifier: Contains a water pan and a drum with an absorbent sleeve.
- Under Duct Humidifier: Installed through the bottom of ductwork for central humidification.
Water Quality
- Demineralized Water: Treated to remove minerals.
- Soft Water: Low mineral content, natural water like rainwater.
- Medium Hard Water: Untreated water with 5 to 15 grains/gal. of mineral content.
- Softened Water: Ion exchange replaces minerals with sodium salts.
- Very Hard Water: Contains over 15 grains/gal. of mineral content.
Humidity and Comfort
- Ideal indoor relative humidity for human comfort is between 30% and 50%.
- Portable humidifiers are recommended for humidifying single rooms.
Additional Considerations
- Overflow outlet of whole house humidifiers must be at least 1" above open drain to prevent siphoning back into the potable water supply.
- Dehumidifiers function by maintaining coil temperatures below the dew point to remove moisture.
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Description
Explore key terms related to humidity and its management through humidifiers in this chapter 35 quiz. Understand concepts like relative humidity, atomizing humidifiers, and evaporative humidifiers. Test your knowledge and enhance your understanding of how these systems work.
