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Model 1137 Humidifier Installation Manual
7. Connect drain hose to 5/8" spout on humidifier
cabinet using hose clamp provided. Run 5/8"
hose to suitable drain such as floor drain, sewer
or laundry sink. Be sure hose has continuous
slope and is not kinked at any point.
8 Turn on water supply and plug in power cord to check operation of humidifier. Set humidistat to a
demand setting. With the furnace off, the solenoid valve should be closed and the humidifier fan not
running. Start the furnace, the solenoid valve should open and the humidifier fan run when the blower
or burner circuit is energized. Check flow of water through distributor trough and evaporator pad. The
standard 990-16-76 orifice will supply approximately 3.5 GPH of water at a line water pressure of 60
psi. For low water pressures (20-40 psi) a larger orifice 990-16-75 is available to provide the same flow.
Leave humidistat set at the recommended setting.
Installation Cont.
• The operating principle of the humidifier is based on the most efficient and economical means of evaporating
water to the air. The heat necessary for evaporating water is produced by the furnace.
• The water supply to the humidifier is controlled by the electric solenoid valve. The solenoid valve and
humidifier fan are controlled by a humidistat connected through an
isolation relay. The humidistat is designed for wall mounting in the
living area or surface mounting on the return air duct.
• Water flows through a strainer, is metered through an orifice to provide
the proper amount of water, and is supplied to the evaporator pad by
the distributor trough. Air from the warm air plenum is pulled through
the wetted evaporator pad by the humidifier fan and returned to the
warm air plenum to be circulated through the living area. Moisture is
evaporated to the air passing through the evaporator pad.
• Minerals are not blown into the air stream as occurs in atomizing
humidifiers; they are left on the evaporator pad where a high
percentage is carried off with the waste water.
• When the humidifier is installed and operating, no adjustments are
necessary other than setting the control knob on the humidistat to the desired level of humidification.
• To turn the humidifier off, close water supply valve, switch electrical power off and turn humidistat off.
• CAUTION
: Do not set relative humidity too high during cold weather. Excessive humidity may cause
condensation on windows or in walls. Refer to recommended settings as described in the humidistat owners
manual.
How the Humidifier Works
At Outside
Temperature
Recommended
Setting
-20°F
-29°C
15%
-10°F
-23°C
20%
0°F
-18°F
25%
+10°F -12°C
30%
+20°F
-7°C
35%
+30°F
-1°C
40%
!
