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Adjustable TR factory set at 5% rh
3 to 15% rh Low Range
3 to 20% rh High Range
Adjustable TR factory set at 12% rh
7 to 35% rh Low Range
Ambient Operating: 45 to 125F (7 to 516)
Storage: -30 to l5OF (-35 to EC)
1972
The sensed change causes a proportional change in the
branchline pressure (BLP) and changes the control actuator
position by the same proportion. The HP970A (DA) increases
and the HP9708 (RA) decreases the BLP when the relative
humidity increases.
The WP972B (RA) provides an inverse branch pressure
signal in relation to the sensed relative humidity. The wide
throttling range allows a reset of reilative humidity as a
function of the outdoor temperature, preventing condensation
during extreme winter conditions.
The tools shown in Figure 3 and a sling psychrometer or
Digital Relative Humidity Pen CCT915 are necessary to
calibrate the Humidistats.
ig. 3. Calibration Tools.
PEN CCT915
If the Humidistat is in an area where it is exposed to
dust or dirt, periodicaliy remove the cover and use an
air hose or soft brush to remove accumulated dust or
dir-t.
with oil, grease, or dust, remove and clean it by meetly
agitating it in an acetone solution. Dry the element at
room temperature. Re~~sta~~ the efement and recalibrate
the Humidistat.
The throttling range is factory set and should not r~~~~re any
change under normal operating conditions. If a change in
relative humidity causes the system to hunt or the response is
too slow, reset the throttling range as follows:
If the system hunts or the controlled device cycles,
move the throttling range indicator down. If the
response is too slow, move the throttling range ifldicator
up toward minimum.
range is changed.
T H R O T T L I N G
I N D I C A T O R
LOCK SCREW
S E - i - P O I N T /
L O C K I N G S T O P S
Fig. 4. Humidistat with t
N Y L O N
A D J U S T M E N T
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