Honeywell L91B Thermostat User Manual

Wiper on the controller potentiometer moves in response to

pressure changes.

Honeywell

D has 2 potentiometers for unison control of 2 motors.

has a fixed resistor and a manually-adjusted trim

PROPORTI ONI NG

potentiometer in series with the controller potentiometer; for

special applications in electronic bridge circuits.

PRESSURETROLCONTROLLERS

and F models have an adjustable proportioning

throttling) range to allow selection of desired pressure control

range.

(

PROPORTIONING PRESSURETROL CONTROLLERS ARE

SERIES 90 MODULATING PRESSURE CONTROLLERS THAT

PROVIDE DIRECT CONTROL OF MODULATING MOTORS OR

VALVES USED ON AUTOMATIC BURNERS OR STEAM HEAT-

ING SYSTEMS.

Adjustments are made by screws on top of case.

Large, easily-read scaleplates are marked in both customary

(or/in.*, psi, or in. Hg) and metric

or mm Hg) units.

Steel case has clear plastic cover so that pressure settings

Models available for pressure systems up to 300 psi

and potentiometer action can be observed.

Fitting with

NPT threads provides rapid installation.

These controllers may be used with steam, air, noncombust-

ible gases, or other fluids noncorrosive to the brass or

Controller can also be surface mounted by screws through

bronze (300 psi models) bellows.

holes (knockouts) in back of case.

SPECIFICATIONS

TABLE I-MODELS AVAILABLE

.03 to 1.03

0.09 to 0.36

0.21 to 0.76

10 to 63

to 300

to 15 psi

to 150 psi

0.07 to 2.07

0 to 103

23176CF

Yes

30 to 110 psi

1.5 to 12 psi

13 to 52 psi

2413

172

0.03 to 1.03

0.09 to 0.36

225

1551

are marked in both customary

psi, or in. Hg) and Metric

or mm Hg) units.

available with or without steam trap (siphon loop).

‘Includes steam trap (siphon loop).

available with

in. BSP-TR internal threads (British Standard Pipe Threads) for mounting.

resistor and one manually-adjustable trim potentiometer in series with thecontroller potentiometer. Varidus combinations of resistance

models have

values and locations of the fixed resistor and trim potentiometer are available. See Table II.

of active winding is in. mm] for Part No. and in. mm] for Part No. 23176CF.

Table II for potentiometer part number.

D.A.

Form Number 65-0059

@Honeywell Inc. 1966

FINISH: Gray.

MAIN SCALEPLATE: Marked in both customary

psi, or in.

Hg) and Metric

or mm Hg) units.

PROPORTIONING RANGE

and F only):

ADJUSTING SCREW

CONTROLLER

POTENTIOMETER(S)

graduated from A to F with a MIN (minimum) value below A. (See

Table Ill for the value of each division.)

SCALE

ADJUSTING

MOUNTING MEANS: Fitting on bellows has NPT threads

(external on 0 to 16 0 to 4 psi, and 0 to 15 psi models;

internal on all other models) for mounting on a pipe or steam trap

siphon loop).

POTENTIOMETER

SCREW

(

POTENTIOMETER

NOTE: Some models are available with

threads: see Table

BSP-TR internal

WIPER ARM(S)

Also can be surface mounted by screws through 2 holes

knockouts) in back of case.

PROPORTIONING

(

SCALEPLATE

ONLY)

PROPORTIONING

INDICATOR

TABLE

F RESISTANCE VALUES AVAILABLE

(

L91B.D.F ONLY)

B E L L O W S H O U S I N G

I n Bl e ga

11. 2 23367F

17. 6 233676

4 .

4 7 0 518

8 7 0

R- B

4. 8

l e g b

3 8 0 . 0

6 .

2 0 8 0 2515

MAIN SCALE

SETTING

I N D I C A T O R

f or Ot o 15 psi [O t

model s onl y.

a nd 5t o 150 ps i

KNURLED ADJUSTMENT KNOB ON

TO 2.07 MODELS.

PSI

E l 2 7 5

f or Ot o 15 ps i I Ot o 103

t o 1. 03

mode l s .

Nomi na l

r e s i s t a nc e va l ue s .

adjustable trim potentiometer is

ohms (nominal) in all

models. With zero pressure on the bellows, adjust the trim potentiometer to

obtain the resistance values listed between terminals and or between

terminals and W, as indicated.

FIG.

SETTING AN

CONTROLLER.

PROPORTIONING

TABLE III-APPROXIMATE VALUE OF EACH DIVISION

MODELS:

(A TO

B TO C. etc.) ON PROPORTIONING (Throttling)

RANGE SCALEPLATE

only)

potentiometer; nonadjustable proportioning

range.

OPERATING

RANGE

VALUE OF EACH

DIVISION

B-single potentiometer; adjustable proportioning range.

potentiometers allow unison control of 2 motors;

adjustable proportioning range.

F-single potentiometer; adjustable proportioning range;

fixed resistor and manually-adjustable trim potentiometer in

series with controller potentiometer.

CUSTOMARY UNITS METRIC UNITS CUSTOMARY UNITS METRIC UNITS

ELECTRICAL RATING: 24

POTENTIOMETER ACTION: Wiper moves toward

on pressure

rise; toward

replaceable.

on pressure fall. Potentiometer is field

2 to 50 psi

14 to 345

to 1.03

4.7 psi

7.8 psi

32.4

psi

0 . 0 5 4

POTENTIOMETER RESISTANCE: 140 ohms (nominal) for

and D models; see Table II for F models.

PRESSURE SENSING ELEMENT: Phos-bronze bellows.

t o

1. 03

6. 7 ps i

0 . 0 4 6

MAXIMUM AMBIENT TEMPERATURE: 150 F

C].

MINIMUM AMBIENT TEMPERATURE: 32 F [0 C].

ADJUSTMENT MEANS: Screws on top of controller case; knurled

10 to 300 psi

with

0.07 to 2.07

16.4 psi

0.113

in.

knob for main scale setting on 10 to 300 psi

to 2.07

models.

0 to 300 psi

with

in. pot.)

0.07 to 2.07

13.8 psi

0.095

SET POINT: At low pressure end of proportioning

throttling) range.

WEIGHT: 116.15 oz.

(

kg].

PRINTED IN U.S.A.