LP907A AIRSTREAM INSERTION THERMOSTAT
Adjustments
Refer to Fig. 8 and the Maintenance section.
Throttling Range
IMPORTANT
— Always check calibration after adjusting the throttling
range.
— Set the throttling range as near to the minimum value
that the system permits without causing short cycling.
NOTE: For unit ventilator use, the throttling range is factory
set at 25°F (14K) and requires no further adjustment.
TO CHECK THE ACTUAL THROTTLING RANGE:
1. Turn the setpoint dial until branch line pressure (BLP) is
less than 1 psi (7 kPa).
2. Turn dial counterclockwise until BLP is 3 psi (21 kPa)
and note setpoint.
3. Continue to turn the dial until BLP is 13 psi (90 kPa).
4. The difference between the setpoints at 3 and 13 psi
(21 and 90 kPa) BLP is the throttling range.
TO ADJUST THE THROTTLING RANGE:
1. Loosen the throttling range indicator locking screw with
the thermostat key. See Fig. 8.
NOTE: If there is no locking screw, simply squeeze the
throttling range adjustment clip to release it.
2. Slide the indicator until its leading edge is on the
desired setting.
IMPORTANT
When replacing the cover, be careful not to disturb
the throttling range adjustment clip.
Calibration
NOTE: Calibration procedures are the same for all models
with the exception that the LP907B (or LP907A used
with an RP670) cannot be calibrated unless the relay
main air pressure supply is 18 psi (124 kPa).
1. Loosen the setpoint-dial locking screw.
2. With 3/16 in. (5 mm) open-end wrench, turn the setpoint
adjustment screw until the primary lever is parallel with
the base.
3. Turn the calibration screw until the nozzle lever is
parallel with the base.
4. Adjust the setpoint dial until the setpoint indicator
matches the current temperature at the sensing element.
5. Tighten the setpoint-dial locking screw.
6. Adjust the calibration screw until BLP is 8 psi (55 kPa).
7. Turn the setpoint dial to the desired setpoint.
IMPORTANT
When replacing the cover, be careful not to disturb
the throttling range adjustment clip.
BASE
PRIMARY
LEVER
NOZZLE
LEVER
CALIBRATION
SCREW
SETPOINT
INDICATOR
SETPOINT
DIAL
LOCKING
SCREW
SETPOINT
ADJUSTMENT
SCREW
SETPOINT
DIAL
THROTTLING
RANGE
ADJUSTMENT
CLIP
INSET "A"
THROTTLING RANGE
INDICATOR LOCKING
SCREW
GAGE
ADAPTER
GAGE
TEE
TANK
VALVE
M17677BB
Fig. 8. LP907A Adjustments.
TROUBLESHOOTING
1. If the LP907 does not operate smoothly when making
an operational check, replace the filter (located between
the gage tee and device base).
2. If results do not improve, check the pneumatic line
restriction to determine whether there is proper airflow.
3. If the pneumatic line has evidence of oil, purge the line
with refrigerant and eliminate the source of oil.
IMPORTANT
Keep oil out of the pneumatic line to avoid recurring
problems.
Home and Building Control Home and Building Control
Honeywell
Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North
35 Dynamic Drive
Golden Valley, MN 55422
Scarborough, Ontario
M1V 4Z9
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