INSTALLATION |] 
INSTRUCTIONS 
TYPES H41, H61 HUMIDITY CONTROLLERS 
Control of either humidifying or dehumidifying equipment is obtained with these 
sensitive Humidity Controllers. The operating element is made up of strands of human 
hair which contract or expand with changes in relative humidity and in turn operate 
a mercury switch. 
The H41 and H61 models may be used in either low or line voltage circuits. 
SPECIFICATIONS 
TYPES— Electrical Rating in Amperes: 
H41A— Opens circuit on humidity rise (S.P.S.T.). | 115V. 230 V. 
H41B—Closes circuit on humidity rise (S.P.S.T.). “Rynning iircakod Running | Locked 
H61A—Closes circuit on humidity rise. Fur- | Current Rotor Current | Rotor 
nished with a Series 60 (S.P.D.T.) switch. “AC. | LO are ee? i 
Dice 1.0 —— Ss —— 
FINISH—Silver. (Special finishes available at 
extra cost. Submit sample). 
RANGE — 20 to 80% Relative Humidity. 
DIFFERENTIAL — Non-adjustable. H41: 3%, 
H61: 5%. 
OPERATING ELEMENT—Human hair. 
ADJUSTMENT MEANS— External knob. 
SPECIAL FEATURES AVAILABLE—(at extra 
cost). 
1. Type Number. 
DIMENSIONS—Height 539”, width 34”, depth 
Sir. 
Locking cover with key set. 
WHEN ORDERING SPECIFY: 
2. Special features required. 
INSTALLATION 
GENERAL — The Humidity Controller should always be 
mounted on a wall in the space being humidified (or dehumidi- 
fied) except when used with a central fan heating or air 
conditioning system supplying air to more than one room. In 
the latter case it should be mounted in the return air duct. 
When located in the room, the Humidity Controller should 
be mounted about five feet above the floor where it will be 
affected only by the average temperature and relative humid- 
ity of the room (not on an outside wall). There should be no 
obstruction to free circulation of air over the controller such as 
furniture or doors. Do not mount the controller where it may be 
affected by drafts, hot or cold air from water pipes or ducts, 
radiant heat from the sun or fireplace, etc. 
These Humidity Controllers are intended principally for the 
usual air conditioning applications. Where unusual tempera- 
tures, corrosive atmospheres, or extremely high humidities 
are expected, consult our Engineering Department for recom- 
mendations. 
MOUNTING—1. Mount a standard wall switch box in the 
wall about five feet above the floor or in the duct (See para- 
graph 6) at a suitable location and run the wiring to the box in 
conduit, BX, or thermostat cable. Be sure that all wiring 
complies with local electrical codes. 
2. Remove the wall plate from the base of the controller by 
loosening the screw in the bottom end of the base. 
3. Fasten the wall plate to the switch box with the two 
moumting screws furnished. Note the pendulum leveling 
indicator on the plate and see that the plate is mounted level. 
Do not distort the base by tightening the mounting screws too 
tightly. If the wall surface is uneven, shims should be placed 
under the wall plate to prevent it from being distorted when 
the screws are tightened. 
4. Strip 34” of insulation from ends of connection wires and 
fasten them to the proper terminals on the base of the con- 
troller. 
5. Fasten the Humidity Controller in position over the wall 
plate by engaging the two holes in the top of the base with the 
prongs on the wall plate. Then tighten the screw in the bottom 
end of the base. 
6. Duct Mounting—If the Humidity Controller is to be 
located in a duct, it should be mounted on a removable or 
hinged-access door to facilitate inspection and setting. A sheet 
metal shield should be placed ahead of the controller to 
prevent air at high velocity from passing through it. 
March 26, 1948 
Supersedes Form 95-1199A 
Dated February 15, 1945 
PAGE 
HUMIDITY 
CONTROLLER WALL PLATE 
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H41A&B 
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BACK VIEW 
OF 
CONTROL 
Fig. 1—Assembly of Controller and wiring connections. 
(See Fig. 5 for Terminal Arrangement of older models.) 
HUMIDITY 
SHIELD mn CONTROLLER 
SWITCH BOX 
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GREENFIELD 
CONDUIT 
Fig. 2—Method of mounting on access door. 
Ho ee SECTION 3A 
ELECTRIC HUMIDITY CONTROLLERS 
Order This Sheet by 
Form Number 95-1199A 
