Unit 60

What is the desirable amount of relative humidity that should be maintained?

30%-60%

How is steam humidifier operation different from evaporative operation?

A steam provides energy required to evaporate the water and doesn't rely on heat in the air. Steam humidifiers can control the system fan to provide humidification on demand, even if there is no call for heat

Explain how a bypass humidifier works

Air flows from the supply plenum, through the humidifier and into the return plenum. Water evaporates into the air when the dry, warm air passes over the moist media in the humidifier

Why do most humidifier require annual cleaning and media replacement?

Because minerals in the water are left behind in the sump and media when the water evaporates

Why should a steam humidifier be filled with water before it is energized?

Because the heating element will burn out quickly without water

Why should the humidity level in the house be reduced as the outdoor temp drops?

Condensation begins to form on the inside of cold building surfaces when the surface temp drops below the dew point of the air

Which types of humidifier requires the least cleaning?

Evaporative humidifiers

What advantages are there to adding humidity to heated air?

It can help save energy in the winter for promoting comfort at lower temps

What are the two most common controlling elements in a mechanical humidistat

Nylon ribbon or Hair

Why do steam humidifiers require heavier electrical wiring than bypass type humidifiers?

The power wiring required for vaporizing and steam humidifiers is much heavier then other types of humidifiers because of the increased element power needed to heat water

How can an improperly maintained humidifier contribute to bad indoor air quality issues?

The water dump in some types of humidifiers can grow algae and mild if not properly maintained

What are the two general categories of humidifiers?

Those that rely on on heat in the air to evaporate the water and those that supply their own energy for evaporating the water

What is the purpose of the flush cycle used in some steam humidifiers?

To flush out minerals left behind from water evaporation

What types of humidifiers work well with heat pump systems?

Vaporizing, steam, or bypass humidifiers

On what types of heating systems can atomizing humidifiers be used?

Warm air furnaces not heat pumps