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14002573-001 HP970 HUMIDISTAT AND TP970 THERMOSTAT MODERNlZATlON KIT
Digital Relative Humidity indicator Pen CCT915 or other
accurate rh measuring device
Pressure Gage 14003519-001 (0 TO 30 psi [0 to 207 kPa])
Gage Adapter MQP729 (CCT729)
Thermostat Tool MQT735A (CCT735A)
ange Adjustment
The throttling range is factory set and should not require any
change under normal operating conditions" If a change in
relative humidity causes the system to hunt, reset the
throttling range as follows:
Slide the throttling range indicator (Fig. 18) to the
desired indication on the scale.
Move the throttling range indicator up toward minimum
on slow response or move it down if hunting or cycling
of the controlled device occurs.
Recalibrate the Humidistat each time the throttling
range is changed.
G A G E T A P
T H R O T T L I N G
I N D I C A T O R
C A L I B R A T I O N
L O C K S C R E W
L O C K I N G S T O P S
18. Humidistat with the cover off showing the
adjustment points.
95-7135
T H R O T T L I N G
R A N G E
S C A L E
( M I N I M U M U P )
N Y L O N
L E M E N T
A D J U S T M E N T
Calibration Check
Measure the rh with a Digital Relative Humidity
Indicator Pen CCT915 or other accurate rh
measuring device,
Turn the setpoint adjustment until the setpoint indicator
reads 10 percent below (HP970A) or above (HP9706
and HP972B) the indicated rh and allow the Humidistat
to build up BLP.
Turn the setpoint indicator up (HP970A) or down
(HP970B and HP972B) slowly using the
setpoint adjustment.
If the Humidistat bleeds off at
indicated humidity, no further calibration is necessary, If
the Humidistat does not bleed off properly, proceed with
RECALIBRATION.
Humidistats are sensitive. Handle them with extreme
care during calibration. Do not breathe directly on the
element when the cover is off.
Ensure the system is stabilized and the main line is
maintained at normal pressure between 13 and 21 psi
(90 and 145 kPa). Factory calibration is 18 psi
(125 kPa).
Install the Pressure Gage into the gage tap (Fig. 4)
using the Gage Adapter.
Measure the rh with a Digital Relative Humidity
Indicator Pen CCT915 or other accurate rh
measuring device.
Use the setpoint adjustment to set the setpoint indicator
at the actual relative humidity.
Adjust the calibration screw (Fig. 18) until the Pressure
Gage reads 0 psi (0 kPa).
Readjust the calibration screw slowly until the Pressure
Gage reads 8
psi (55
Allow sufficient time for a complete response and
stabilization, then recheck pressure. The Humidistat is
now calibrated.
Remove the Pressure Gage and Gage Adapter.
NOTE:
If the gage tap fails to seal properly after the
Pressure Gage is removed, bleed off a small
amount of air and insert Gage Tap Plug
14002172-001 into the gage tap.
Set the Humidistat at the desired setting.
Proceed to HUMIDISTAT/THERMOSTAT
COVER MOUNTING.
percent rh of the
kPa).
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