General 45 Owner's Manual

General Aire Humidifier Owners Manual

This is a basic humidifier diagnostic tool for the complete line of General
Aire humidifiers. Most of the modern models have complete installation and
owner's manuals located on their perspective pages on this website. Go to
their specific page to locate it. This is a basic tool which covers the most
typical problems on most humidifiers.

General 709, 990, 1040, 1042, SL-16, and 1099 Series Power Humidifiers

This manual is an aid to servicing and troubleshooting General 709, 990, 1040,
1042, and 1099 Series power humidifiers. These humidifiers operate on the most
efficient and economical means of evaporating water to air. Air circulation, water
distribution and electrical circuitry all function in an elementary manner providing the
utmost in simplicity and therefore the highest degree of reliability.

Models 709, 990, 1040, 1042, SL-16, and 1099 (Drain Models)

Air circulation in these humidifiers is based on the bypass principal. Warm air is
bypassed from the warm air plenum or positive pressure side, through the
humidifier, and then to the return air or negative pressure side of the blower system.
At typical bonnet pressures, 150 to 200 CFM will move through the humidifier. The
air flow may be controlled with the manual air control. Closing the manual control
will reduce the evaporative capacity of the humidifier.

The water supply for drain type humidifiers is controlled by the electric solenoid
valve connected in parallel with the furnace blower circuit. The water flows through a
monel wire cloth filter, through a metering orifice to provide the proper amount of
water, and to the distributor trough to be evenly distributed over the top of the
evaporator pad,.

The evaporator pad is coated with a non-soluble wetting agent to increase
humidifier efficiency. Some of the coating may dust off during transit. This will not
affect the efficiency of the evaporator pad. In operation, the water flows from the "V"
notches in the distributor trough, down through the pad, and aided by the wetting
agent, to almost all surfaces of the evaporator pad. As warm air moves through the
pad, a percentage of the water is picked up by the air through evaporation. This
percentage of evaporation is affected by the temperature of the air, its relative
humidity and quantity of air moving through the humidifier. Excess water is collected
by the drain pan and is carried off by the drain hose to a suitable sewer or drain
connection. The excess water performs a useful function in washing down the
evaporator pad to remove some of the minerals and dust that collect on the pad. The
709, 990, 1040, 1042, and 1099 are evaporative humidifiers. Minerals are left on the
pad and are not blown into the air stream to collect in the living area.

The standard orifice will supply approximately 3.5 GPH of water on the 709, 990,
1040, and 1042 models and 4.8 GPH on the 1099 model, at a line water pressure of
60 psi. For low water pressure (20-40 psi) a slightly larger orifice is available to
provide the same flow at the lower pressure. At typical water rates, the water
consumption will cost approximately $1.50 per month.

Models 709-L, 990-L, 1040-L, SL-16, 1099-L, 709-LH, 1040-LH, 1042-LH,
and 1099-LH

These humidifiers are identical to the drain models except that a 24V. solenoid
valve and transformer are supplied allowing a 24V. control circuit. This facilitates
wiring a humidistat located in the living area or return air duct. The low voltage
humidistat is included in the 709-LH, 1040-LH, 1042-LH, and the 1099-LH models.

Models 709-R, 990-R, 1040-R, 1042-R, 1099-R (Recirculating Models)

These models are variations of the drain models, eliminating the need for the
external drain or sewer.

The electric solenoid valve is eliminated and the water supply is controlled by a
motor driven, adjustable flow pump. The pump is mounted in a reservoir where the
water level is maintained by a float valve. The pump supplies water to the distributor
trough where it is evenly distributed to the evaporator pad. Water that is not
evaporated drains back into the reservoir and is recirculated. The pump motor is
connected in parallel with the furnace blower circuit. A line voltage humidistat may
be installed for automatic control.

If low voltage control is desired for the recirculating models, a Honeywell RA89A
low voltage relay may be used for this purpose.

Troubleshooting

The following guide to troubleshooting 709, 990, 1040, 1042 and 1099 Series
humidifiers lists problems that occasionally occur, their cause and correction.
Troubleshooting is a process of elimination. A complaint or problem exists and by
noting all possible causes, the fault can be located by inspection and test.

Problem

Cause

Correction

Plugged orifice or orifice
strainer.

Disassemble and clean orifice
on inlet side of solenoid valve.

No electric power to
humidifier.

Replace blown fuse.

Reset circuit breaker.

Furnace fan not running when
humidifier is wired per
instructions, furnace fan must
be running for humidifier to
operate.

If humidistat is applied check
for proper setting.

Solenoid valve not opening.

Solenoid will make audible
click when energized. With
furnace blower running and
humidistat turned on high
humidity, check circuit for
loose connections. Check
continuity through solenoid
cell.

No water flow.

Saddle valve closed or

Open valve and check for