Справочник Пользователя для Honeywell L91D

60-2152—08

8

After the controller is installed, wired, and set, it should be 

tested with the system in operation. First, allow the system to 

stabilize. Then, observe the operation of the controller while 

raising and lowering its setpoint. Pressure should increase 

when the setpoint is raised and decrease when the setpoint is 

lowered. Use accurate pressure testing equipment when 

checking out the controller. Do not rely on inexpensive gauges. 

The controllers are carefully calibrated at the factory.

Make sure the modulating motor or modulating valve actuator 

reaches the low- and high-fire positions at the proper points. If 

the motor or actuator runs in the proper direction when the 

setpoint is adjusted, assume that the controller is operating 

properly. If it runs in the wrong direction, reverse the B and W 

wires. Observe the action of the motor or actuator until it 

stabilizes. If the motor or valve is moving constantly, widen the 

proportioning range (not adjustable on an L91A) incrementally 

until the system is stable.

If the controller is suspected of operating improperly, it may be 

further checked by:

1. Leaving the controller installed where it is, but discon-

necting all power to the controller motor or valve.

2. Loosening the cover screw below the main scaleplate 

and removing the cover.

3. Disconnecting the wires from the controller.

4. Connecting an ohmmeter between controller terminals B 

and W to measure the resistance for the potentiometer in 

the controller. The ohmmeter should read about 135 

ohms for an L91A,B, or D.

5. Connecting the ohmmeter between controller terminals 

W and R (Fig. 8) and raising the setpoint of the controller 

above the actual pressure being measured. The ohmme-

ter should read the full value of the potentiometer mea-

sured in step 4 (135 ohms for an L91A,B, or D).

6. Slowly lowering the setpoint of the controller while 

observing the ohmmeter reading. The resistance should 

drop to zero at some setpoint below the actual pressure.

7. Making an approximation of the proportioning range by 

observing the change in setpoint required for a resis-

tance change from zero to full value.

8. When the controller is operating properly, reconnecting 

the wires, replacing the cover, tightening the cover 

screw, and resetting the controller to the desired value.

9. Reconnecting power to the controlled motor or valve. 

Do not put the system into service until you have 

satisfactorily completed all applicable tests described in 

this Checkout section, all tests in the Checkout section 

of the applicable instructions, all tests for the flame 

safeguard control, and any tests required by the burner 

and boiler manufacturers.

DIFF.

MAIN

MIN

B

D

F

E

C

A

0

4

6

2
1

3

4

5

16
14
12
10

8

0

kPa

 OZS

  IN

2

DIFF. IS

ADDITIVE

2

6

7

M8546A

PROPOTIONING 

RANGE ADJUSTING

SCREW

(L91B,D ONLY)

INPUT

OUTPUT

ZERO

ADJ

0

135

W

W

R

R

B

B

SETPOINT

INCREASE

MAIN SCALE

ADJUSTING SCREW

MAIN SCALE

SETTING

INDICATOR

INCREASES TO

135 OHMS

OHMMETER

1     KNURLED ADJUSTMENT KNOB ON 10 TO 300 PSI [0.07 TO 2.07 MPA]

       MODELS.

2     TERMINALS ARE LABELED

3     135 OHMS ON L91A,B OR D.

3

2

1