LP907A AIRSTREAM INSERTION THERMOSTAT
VP512A
VALVE
R.A.
O.A.
MP516A
OPERATOR
ROOM
THERMOSTAT
LP907A
D.A.
M
B
M
H
C
FAN
H L
RP418 E-P
RELAY
WIRE IN PARALLEL
WITH FAN MOTOR
M5419B
Fig. 5. Typical operation.
R.A.
O.A.
MP516A
LP907A
D.A.
M
B
M
FAN
TP972
RP670
WINTER
18 psi (1.24 BAR)
SUMMER
13 psi (.90 BAR)
FACE AND BY-PASS
MP516A
H L
RP418 E-P
RELAY
WIRE IN PARALLEL
WITH FAN MOTOR
M5448B
Fig. 6. Typical operation of LP907A in heating-cooling
application (unit ventilator).
M
M5450
LP907A
VP514
14002913-002
0.007 IN. RESTRICTION
(NOT FURNISHED)
Fig. 7. Typical operation of duct mounted LP907A.
Operational Check
LP907A
1. Ensure BLP ahead of the restriction (or MP516B)
equals mainline pressure. If it does not:
a. Adjust the room thermostat in order to obtain equal
pressure.
b. Decrease the air temperature at the device sensing
element or increase the setpoint.
RESULT:BLP to the valve should decrease, and
vice versa.
c. Return setpoint to the original setting.
LP907B, or LP907A with RP670A Switching Relay
1. Supply 13 psi (90 kPa) main air pressure to the LP907B
relay, or 18 psi (124 kPa) main air pressure to the
RP670A, to simulate summer operation.
2. Block BLP to the LP907 to ensure temperature changes
at the sensing element do not affect room thermostat
control of system operation.
3. BLP to the valve should settle to equal thermostat BLP.
NOTE: The restriction can cause a slight delay in
pressure settling.
4. Supply 18 psi (124 kPa) main air pressure to the relay.
5. Perform the LP907A operational check.
Calibration Check
When BLP equals 8 ± 1 psi (55 ± 7 kPa) with the air
temperature at setpoint, the controller is properly calibrated.
3
95-1612EF
