Aprilaire 220 Service Manual page 6

EXAMPLE: The supply water line fills the quart jar in 2 min. 30 sec. or 150 sec. 7,509
divided by 150 = 50.1 lbs./hr. The quart jar was filled with water from the drain in 2 min.
50 sec. or 170 sec. 7,509 divided by 170 = 44.2 lb./hr. The difference between 50.1 lb./hr.
and 44.2 lb./hr. is 5.9 lb./hr. This calculates out to 0.7 gals. per hour.
1 qt. 2.086 lbs.
150 sec.
1 qt. 2.086 lbs.
170 sec.
Prior to making an evaporation check on an Aprilaire furnace mounted humidifier, set the ther-
mostat and humidistat so that the furnace and humidifier will run without cycling for at least
5 minutes. Allow the humidifier to operate for a minimum of 2 minutes before checking the
time to fill the quart jar at the supply and drain.
The design feed rate is 3 gph for the Models 110, 220, 550, 550A, 558, 560, 560A, 568 and 600.
This feed rate will fill a quart jar in 5 minutes. The design feed rate for the Models 112, 224, 330,
350, 360, 440, 760, 760A, 768 and 700 is 6 gph. This feed rate will fill a quart jar in 2-1/2 minutes.
The Aprilaire furnace mounted humidifiers must have an average air temperature of 120ºF to
evaporate rated capacity.
The water temperature of the Model 330, 350 & 360 must be 140ºF when checking evapora-
tion rate.
EVAPORATIVE CAPACITY
Model 760, 760A, 768 & 700
0.75 gals. water/hr
at 120ºF plenum
temperature
MODELS 220, 224, 440, 445, 448, 550, 558, 560, 568, & 600
Total Static Pressure Drop Across Supply & Return Plenum . . . . . . . . . . . . . . . . .0.2"
Models 550,550A & 558 .....................................................................0.50 gph
Models 400,560,560A, 568 & 600 ......................................................0.70 gph
Models 445,445A & 448 .....................................................................0.75 gph
Model 220.......................................................................................0.40 gph
Models 224, 440 ..............................................................................0.70 gph
Level Unit — The unit or distribution tray must be level so that the water will be evenly dis-
tributed over the entire width of the Water Panel evaporator. If the full width of the Water
Panel evaporator is not wetted, the capacity will be reduced.
Water Feed System (All Units Except Models 445, 445A, & 448) — The water supply starts
from a saddle valve attached to a water pipe. The valve should be completely open. Water
flows to the unit through a 1/4" copper tube to a solenoid valve equipped with an in-line water
strainer. The valve electrically opens and closes to control the supply of water, and the
strainer filters particles from the water. Filtered water then goes through the orifice which
meters the water through the 1/4" tube to the distribution tray. From the distribution tray,
water flows by gravity into the Water Panel evaporator where part of the water is evaporated.
The overflow water flushes the majority of the minerals left after evaporation off the Water
Panel evaporator, through the 1/2" drain spud at the bottom of the unit through the drain line
to the floor drain. Note: With the Model 400, water that is not evaporated initially is contained
and then wicked up by the water panel to be evaporated at a later time.
To clean orifice, gently insert a fine needle through the small opening. As an alternative, use a
drill to clean out the opening: use a #77 drill (0.018" dia.) for Models 110, 220, 400, 550, 550A,
558, 560, 560A, 568 & 600; use a #73 drill (0.024" dia.) for Models 112, 224, 330, 350, 360,
440, 760, 760A, 768 & 700. If the opening cannot be cleaned out or is enlarged, replace with
new orifice (white for the 110, 220; red for the 112, 224, 330; blue for the 350, 360, 440, 760,
760A, 768, 700; yellow for the 400,550, 550A, 558, 560, 560A, 568, 600). Models 445, 445A &
448 have no orifice.
3600 sec.
qt. hr.
3600 sec.
qt. hr.
Model 110
0.55 gals. water/hr
at 120ºF plenum
temperature
7509
= =
150
7509
= =
170
Model 112
0.85 gals. water/hr
at 120ºF plenum
temperature
- 5 -
50.1 lbs./hr.
50.1 lbs./hr.
–44.2 lbs./hr.
5.9 lbs./hr.
44.2 lbs./hr.
Model 350 & 360
0.5 gals. water/hr
at 140ºF
service hot water
EVAPORATIVE CAPACITY
at 120ºF Plenum Temperature