Submittal Sheet

4
LP916A-C PNEUMATIC REMOTE BULB THERMOSTATS
75-5559
OPERATION
LP916A (Direct Acting)
When temperature at the sensing element falls below setpoint
of the LP916A, branchline pressure to the normally open
(n.o.) valve is lowered, and the valve is modulated open to
maintain setpoint temperature.
LP916B (Reverse/Direct Acting)
With main-line pressure at 13 psi (90 kPa) for all except
LP916B1058 which requires 9 psi (62 kPa), the LP916B
operates reverse acting. As the sensed temperature
increases, the branchline pressure decreases and chilled
water flow increases with a n.o. valve.
With a high main-line pressure of 18 psi (124 kPa) or above,
the LP916B operates direct acting. As the sensed
temperature increases, the branchline pressure increases
and hot water flow decreases with a n.o. valve.
LP916C (Reverse Acting)
When the LP916C is used with a normally open valve for
cooling, branchline pressure drops with a rise in sensed air
temperature and the n.o. valve is modulated open to maintain
setpoint temperature.
MAINTENANCE
EQUIPMENT REQUIRED
— Commercial Cleaning Solvent or Degreaser.
— Gage Adaptor CCT729A.
— Gage 305965, 0 to 30 psi.
— 5/64-inch Hex wrench.
WARNING
Careless handling of solvents can result in permanent
damage to the respiratory system or skin. Avoid
prolonged inhalation of vapors or contact with skin.
CLEANING
Remove cover. Use cleaning solvent to clean all surfaces.
Clean the element and capillary tubing, making certain
neither is damaged or kinked. Do not bend the capillary
tubing in a short radius.
OPERATIONAL CHECK
Use gage adaptor. Insert the gage into the gage tap (Fig. 5)
on the front of the device. Set main-line pressure to 18 psi
(124 kPa), or 13 psi (90 kPa) for LP916B Summer
application. Slowly turn the setpoint knob above and below
bulb ambient temperature. The branchline pressure should
vary from 3 to 13 psi (21 to 90 kPa) pressure, or 13 to 3 psi
(90 to 21 kPa) for reverse acting application within the rated
throttling range. If operation is not satisfactory, recalibrate and
recheck (see CALIBRATION). Turning the knob to above 13
psi (90 kPa) should build branch line to within 2 psi (14 kPa)
of main.
Fig. 5. LP916 Gage tap location.
GAGE TAP
C2861
COOLER
NORMAL
WARMER