Honeywell Pressuretrol L404 Series User manual

L. Z. • Rev. 3-95 • ©Honeywell Inc. 1995
L404A-D,F; L604A,L,M
Pressuretrol® Controllers
CONTENTS
Specifications ................................................ 2
O de ing Info mation.................................... 2
Installation .................................................... 5
Setting and Checkout..................................... 8
Se vice Info mation ..................................... 10
L404 and L604 P essu et ol® Cont olle s a e
line voltage p essu e cont olle s that p ovide ope -
ating cont ol, automatic limit p otection, o manual
eset limit p otection fo p essu e systems of up to
300 psi (21.1 kg/cm2 o 2068 kpa).
■Screw adjustments made on top of case.
■Scaleplates marked in English (psi) and Metric
(kg/cm2) units.
■L4 4F models available with European enclosure,
British Standard Pipe Threads, ground screw, and
scaleplates marked in kg/cm2 and either psi or kPa.
■Clear plastic cover on case to observe pressure set-
tings and switch action.
■Leveling indicator visible through cover.
■Hexagonal fitting with 1/4-18 NPT internal threads
for direct mounting to 14 26 Steam Trap (siphon
loop).
■Surface mount is available using screws through
holes (knockouts) in case backing.
■Can be used with steam, air, non-combustible gases,
or fluids non-corrosive to the pressure sensing ele-
ment.
■Stainless steel diaphragm (except 3 psi [21.1 kg/
cm2 (2 68 kPa)] models) also allows use with am-
monia, oxygen, distilled water, and similar media.
■L4 4B is recommended for supervision of atomiz-
ing medium pressure in oil burner systems.
■Models are available with spst, spdt, or dpst switch-
ing and in variety of operating ranges.
■Dustproof, trouble-free mercury switches (all mod-
els except L4 4F, which has snap-acting switch).
■Automatic reset models have adjustable, subtractive
differential (except L6 4M).
■Trip-free mechanism on manual reset models as-
sures that limit function of controller cannot be
defeated by jamming reset lever.
60-2150-10

6 -215 —1 2
L404A-D,F; L604A,L,M
SPECIFICATIONS • ORDERING INFORMATION
Specifications
TRAD LIN ® MOD LS
TRADELINE® models are selected and packaged to
provide ease of stocking, ease of handling, and maximum
replacement value. Specifications of TRADELINE® con-
trols are the same as those of standard models except as
noted below.
TRADELINE® MODELS AVAILABLE:
L6 4A Pressuretrol® Controllers—Available in 2 to 15, 5 to
5 , 1 to 15 , and 2 to 3 psi (.14 to 1.1 kg/cm2 [14 to
1 3 kPa], .4 to 3.5 kg/cm2 [34 to 345 kPa], .7 to 1 .6 kg/
cm2 [69 to 1 34 kPa], and 1.4 to 21. kg/cm2 [138 to
2 68 kPa]) .
ADDITIONAL FEATURES: TRADELINE® pack with
cross-reference label.
STANDARD MOD LS
MODELS: L4 4A-D,F and L6 4A,L,M Pressuretrol® Con-
trollers. See Table 1. A 14 26 Steam Trap (siphon loop)
is available, except where noted in Table 1. The steam
trap is necessary for boiler installations.
SWITCH(ES): Mercury switch(es) in all models except the
L4 4F, which has a Micro Switch snap-acting switch.
PRESSURE SENSING ELEMENT: Stainless steel dia-
phragm (brass bellows in 3 psi [21.1 kg/cm2,
(2 68 kPa)] models).
MAXIMUM AMBIENT TEMPERATURE: 15 !F (66!C).
MINIMUM AMBIENT TEMPERATURE: Minus 35!F
(minus 37!C); also refer to the note in the Location and
Mounting section.
ADJUSTMENT MEANS: Screws on top of controller case.
Scales are marked in psi and kPa.
ELECTRICAL CONNECTIONS: Internal screw terminals;
hole in side of case for 1/2 in. conduit.
MOUNTING MEANS: Hexagonal fitting on diaphragm has
1/4-18 NPT internal threads for mounting on a pipe or
steam trap (siphon loop). Also can be surface-mounted
using screws through two holes (knockouts) in back of
case.
Ordering Information
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the Tradeline
Catalog or price sheets for complete ordering number, or specify—
1. Order number (TRADELINE® model, if desired).
2. Operating range (see Table 1).
3. Model without steam trap, if desired and available (see Table 1, Note b).
4. Optional specifications, if desired (see Table 1).
5. Replacement parts, if desired.
6. Accessories, if desired.
If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:
1. Your local Home and Building Control Sales Office (please check the white pages of your phone directory).
2. Home and Building Control Customer Relations
Honeywell, 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9. International Sales and
Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico,
Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

36 -215 —1
L404A-D,F; L604A,L,M
SPECIFICATIONS
TABLE 1—MODELS AVAILABLE.
aScaleplates are marked in both psi and kg/cm2
bModel available with special fixed low differential. Switch rated for .5A at 12 Vac.
cL4 4A,B and L6 4A models are available with 1 to 6 psi midscale subtractive differential in 2 to 15 psi models.
dBrass bellows replaces stainless steel diaphragm. Not suitable for use with ammonia, oxygen, or other corrosive materials.
eModel available with minimum operating pressure of 1.25 psi ( . 9 kg/cm2 or 8.62 kPa) and minimum subtractive differential of .5 psi
( . 35 kg/cm2 or 3.45 kPa).
fModel available with special fixed low differential. Switch rated for .5A at 12 Vac.
gL4 4C,D and L6 4L models are designated as Manual Reset 2 controllers; the trip-free reset mechanism does not permit the controller to
function as an automatic-reset device when the manual reset lever is held in the reset position. The subtractive differential is fixed at the
minimum value of the adjustable differential of the L4 4A for each corresponding operating range.
hL4 4F only; all other models have mercury switches.
iModel available with sealed bell crank adjustment.
jSpst switches operate in unison; spdt action when jumper is installed between R1 and R2.
kAlso recommended for supervision of atomizing medium pressure (air or steam) in an oil burner system.
SWITCH CONTACT RATING (in amperes at 5 /6 Hz):
aL4 4F (snap-acting) does not have non-inductive or dc ratings.
bL6 4A and L have also been tested (and listed by Underwriters Laboratories Inc.) and breaking (not making) a load with a total
rating of 9.8 A full load, plus 36 VA ignition, plus 25 VA pilot duty at 12 Vac.
Model Load 120 Vac 240 Vac 120 Vdc 240 Vdc
L4 4A Full Load
Locked Rotor
Noninductive
a
8.
48.
1 .
5.1
3 .6
5.
2.4
24.
5.
1.2
12.
2.
L6 4A,L
b
Full Load
Locked Rotor
Noninductive
8.
48.
1 .
5.1
3 .6
5.
2.
2 .
8.
1.
1 .
4.
L6 4M Full Load 1. .5 1. .5
Switching
Action on
Pressure Rise Operating Ranges
a
Midscale Subtractive Differential
a
(Adjustable) Maximum Surge Pressure
Model to Setpoint psi kg/cm
2
kPa psi kg/cm
2
kPa psi kg/cm
2
kPa
L4 4A spst, breaks
circuit 2 to 15
b,c
5 to 5
1 to 15
b
2 to 3
d
.14 to 1.
.35 to 3.5
.66 to 1 .6
1.4 to 21.
14 to 1 3
34 to 345
69 to 1 34
138 to 2 68
2 to 6
4 to 12
8 to 16
15 to 4
.14 to .41
.28 to.82
.56 to 1.1
1. 4 to 2.76
14 to 4
127 to 83
55 to 11
1 3 to 276
5
85
225
5
3.5
6.
15.8
35.2
345
586
155
3445
L4 4B
i
spst, makes
circuit 2 to 15d,
c,e,f
5 to 5
1 to 15
e,b
2 to 3
d
.14 to 1.1
.35 to 3.5
.66 to 1 .6
1.4 to 21.
14 to 1 3
24 to 345
69 to 1 34
138 to 2 68
2 to 6
4 to 12
8 to 16
15 to 4
.14 to .41
.28 to .82
.56 to 1.1
1. 4 to 2.76
14 to 41
27 to 83
55 to 11
1 3 to 276
5
85
225
5
3.5
6.
15.8
35.2
345
586
155
3445
L4 4C spst, breaks
circuit 2 to 15 5 to 5
1 to 15
2 to 3
d
.14 to 1.
.35 to 3.5
.66 to 1 .6
1.4 to 21.
14 to 1 3
34 to 345
69 to 1 34
138 to 2 68
manual reset
(fixed, subtractive differential) 5 85
225
5
3.5
6.
15.8
35.2
345
586
155
3445
L4 4D spst, makes
circuit 2 to 15 1 to 15 .14 to 1. .66 to 1 14 to 1 3 69 to 1 68 manual reset
g
(fixed, subtractive differential) 5 225 3 5 15.8 345 155
L4 4F spdt snap-acting
switch,
h
makes
R-W, breaks R-B
2 to 15
5 to 5
i
1 to 15
2 to 3
d
.14 to 1.
.35 to 3.5
.66 to 1
1.4 to21.
14 to 1 3
34 to 345
69 to 1 34
138 to 2 68
2 to 6
6 to 14
1 to 22
2 to 5
.14 to .41
.41 to .97
.69 to 15.2
1.4 to 3.5
14 to 41
41 to 97
6 to 152
138 to 345
5
85
225
5
3.5
6.
15.8
35.2
345
586
155
3445
L6 4A 2 isolated spst
circuits, or 1
spdt,
j
makes R1-
W, breaks R2-B
2 to 15
c
5 to 5
1 to 15
2 to 3
d
.14 to 1.
.35 to 3.5
.66 to 1
1.4 to21.
14 to 1 3
34 to 345
69 to 1 34
138 to 2 68
2 to 6
4 to 12
8 to 16
15 to 4
.14 to .41
.28 to .82
.56 to 1.1
1. 4 to 2.76
14 to 41
27 to 83
55 to 11
1 3 to 276
25
85
225
5
1.8
6.
15.8
35.2
172
586
155
3445
L6 4L spdt circuit
makes R-W,
breaks R-B
2 to 15 .14 to 1. 14 to 1 3 manual reset
g
(fixed, subtractive differential) 25 1.8 172
L6 4M spdt circuit
makes R-W,
breaks R-B
1 to 15 .66 to 1 .1 69 to 1 34 fixed: 3.5 psi (24.1 kPa) 225 15.8 155

6 -215 —1 4
L404A-D,F; L604A,L,M
SPECIFICATIONS
Fig. 1—Mounting dimensions of the L404A,B,C,D,F and L604A,L,M Pressuretrol Controllers, in in. (mm).
L404A-D,F; L604A,L,M
1/4-18 NPT
1
2
1
2
3
1
3
4-1/2 (114.3) (COVER)
4-11/32 (110.3) (CASE)
3/16 (4.8) X 21/64 (8.3)
KNOCKOUT (2)
1-15/16 (49.2)
3-3/16 (81.0)
1-5/32
(29.4)
2-1/8 (54.0)
2-3/4 (69.9)
1-61/64 (49.6)
1-13/16
(46.0)
1-1/16
(27.0)
13/16
(20.6) 1/2 (12.7)
3-7/8
(98.4)
7/8
(22.2) DIA.
1-1/2 (38.1)
1-3/16 (30.2)
1-1/16
(27.0)
13/16
(20.6)
4-31/32
(126.2)
3-23/32
(94.5)
RESET EVER (ON MANUA RESET MODE S ON Y.)
THIS DIMENSION IS 4-27/32 IN. (123.0 MM) ON 604 MODE S WITH A 2 TO 15 PSI (.14 TO 1.0 kg/cm2 (14 TO 103 kPa)) OPERATING RANGE,
AND 5-3/4 IN. (146.A MM) ON 604 MODE S WITH A 20 TO 300 PSI (1.4 TO 20.7 kg/cm2 (138 TO 2068 kPa) OPERATING RANGE.
ON Y ON 604 MODE S WITH A 2 TO 15 PSI (.14 TO 1.0 kg/cm2 (14 TO 103 kPa)) OPERATING RANGE. M8933
DIMENSIONS: See Fig. 1. See Fig. 2 for mounting steam
trap (siphon loop).
WEIGHT: 2 IBC. ( .91 kg).
FINISH: Gray.
APPROVALS:
Underwriters Laboratories Inc. listed (L4 4A,B,C,D,F;
L6 4A,L,M only): file no. MP466, vol.1 ; guide
no. MBPR.
Canadian Standards Association certified (L4 4A,B,C,D,F;
L6 4A,L only): file no. LR162 ; guide no.4 -E- .
REPLACEMENT PARTS:
129178 Thermoplastic Cover.
14 26 Steam Trap (siphon loop)—1/4 in. black iron pipe.
Necessary for boiler installations.
ACCESSORIES:
33312B Knurled Adjustment Knob—with setscrew; fits
on main scale pressure adjusting screw.
4 74BWJ Limit Stop Assembly—to limit set point ranges;
includes 129564 Range Stop, 1 7194 Range Stop
Screw, and 23466 Wrench.
TABLE 2—CONVERSION TABLE (psi to kPa).
Operating Range Subtractive Differential
Scale-Plate quivalent Scale-Plate quivalent
(psi) (kg/cm
2)
(kPa) (psi) (kg/cm
2)
(kPa)
to 15 to 1 to 1 3 — — —
2 to 15 .14 to1. 14 to 1 3 1 to 6
2 to 6 7 to 4 .14 to .4 7 to 41 14 to 41
5 to 5 .3 to 3.5 34 to 345 4 to 12
5 to 14 .3 to .8 .4 to 1. 28 to 83 41 to 97
5 to 15 .3 to 1 .3 34 to 1 34 — — —
1 to 15 .7 to 1 .3 69 to 1 34 8 to 16
1 to 22 .6 to 1.1 .7 to 1.5 55 to 11 69 to 152
2 to 3 1.4 to 2 .7 138 to 2 68 15 to 4
2 to 5 1. to 2.8 1.4 to 3.5 1 3 to 276 138 to 345

56 -215 —1
L404A-D,F; L604A,L,M
INSTALLATION
Installation
Fig. 2—Right and wrong mounting of a steam
trap (siphon loop), with approximate dimen-
sions in in. (mm).
4-1/2 TO 5-1/2
(114.3 TO 139.7)
BOI ER
14026
STEAM TRAP
(SIPHON OOP)
TEE
PRESSURE
GAUGE
PRESSUR
CONTRO ER
M8934
1
1 1/4 IN. B ACK IRON PIPE WITH 1/4 - 18 NPT EXTERNA
TRHEADS ON BOTH ENDS. BEND THE STEAM TRAP
(SIPHON OOP) TO EVE THE CONTRO ER.
CORRECT
BOI ER
2-1/4
(57.2)
DIA.
INCORRECT
Make all pipe connections in accordance with approved
standards. Use only a small amount of pipe compound to
seal the connection joints. Excess pipe compound can clog
the small hole in the fitting and prevent the controller from
operating properly.
To avoid leaks and damage to the case, use a parallel jaw
wrench on the controller’s hexagonal fitting. Do not tighten
the cont olle by hand by holding the case.
Leveling
A controller with a mercury switch must be accurately
leveled for proper operation. It is level when the leveling
indicator (Fig. 11) hangs freely with its pointer directly
over the index mark inside the back of the case. Level the
controller by carefully bending the steam trap (siphon
loop).
Mounting Alongside a Pressure Gauge
To mount the controller alongside a p essu e gauge
(Fig. 2), remove the gauge. In its place, install a steam trap
(siphon loop) with a tee on top. Using elbows and pipe
nipples, mount the controller and pressure gauge on the
ends of the tee. Level the controller after installation.
WH N INSTALLING THIS PRODUCT. . .
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazardous
condition.
2. Check the ratings given in the instructions and on the
product to make sure the product is suitable for your
application.
3. Installer must be a trained, experienced, flame safe-
guard control technician.
4. After installation is complete, check out product
operation as provided in these instructions.
CAUTION
1. Disconnect power supply before beginning in-
stallation to prevent possible equipment dam-
age or electrical shock.
2. When using the controller with a compressor,
install a dampening device (such as a needle valve,
header, or surge tank) to dampen pulsations that
can damage the controller or reduce its life.
IMPORTANT:
1. Locate the cont olle whe e the ambient tempe atu e
will not exceed 150 ! F (66 ! C).
2. Use pipe compound spa ingly to avoid clogging the
hole in the pipe o diaph agm fitting.
3. Do not tighten the cont olle by hand by holding the case.
4. Accu ately level the cont olle fo p ope ope ation.
LOCATION AND MOUNTING
NOTE: For most accurate operation; add supplemental heat
to installations where the temperature falls below minus
2 !F (minus 29!C). Never locate the controller where the
temperature falls below minus 35!F (minus 37!C), be-
cause mercury in the switch freezes at this temperature.
When used with steam boilers, always mount the con-
troller above the wate line in the boiler. A steam trap
(siphon loop) must always be connected between the con-
troller and the boiler (Fig. 2) to prevent boiler scale and
corrosive vapors from attacking the diaphragm. The loop
on the steam trap must always be perpendicular to the face
of the controller. If the loop is parallel to the controller,
expansion or contraction of the loop tips the controller and
causes the switch to operate inaccurately.
The controller can be mounted (1) alongside the pres-
sure gauge, (2) in a fitting on the boiler provided by the
manufacturer, (3) at a remote location in case of excessive
vibration, or (4) in a special mounting on a low water
cutoff.

6 -215 —1 6
L404A-D,F; L604A,L,M
INSTALLATION
Mounting on a Boiler
If it is not convenient to mount the controller alongside
the pressure gauge, install a steam trap (siphon loop) in the
fitting p ovided by the boiler manufacturer. If there is no
fitting, mount the steam trap at a location recommended by
the boiler manufacturer. Screw the controller directly to the
steam trap, and level the controller.
Mounting at a Remote Location
If there is excessive vib ation at the boiler that can
adversely affect the operation of the controller, mount the
controller at a remote location. All piping from the boiler
must be suitable and solidly mounted. The piping must be
properly pitched to drain all condensation back to the
boiler. A steam trap (siphon loop) must be mounted be-
tween the remote piping and the controller. Level the
controller after installation.
Supervision of Atomizing Medium Pressure
(Air or Steam)—L404B
When air or steam is used as an atomizing medium in an
oil burner system, authorities having jurisdiction (approval
bodies and codes) often require a low limit to prevent
opening the main oil valve until sufficient atomizing pres-
sure is present, and to shut down the system when the
atomizing pressure falls too low.
The L4 4B is recommended for this application. It
makes a circuit when the pressure rises to the set point, and
breaks when the pressure falls to the set point minus the
differential (Fig. 1 ).
WIRING
1. Disconnect the power supply before beginning wiring
to prevent electrical shock or equipment damage.
2. Assume all wiring complies with applicable electrical
codes, ordinances, and regulations. Use NEC Class 1 (line
voltage) wiring.
3. For normal installations, use moisture-resistant No. 14
wire suitable for at least 167!F (75!C) when you are using
the controller with a flame safeguard primary control, or at
least 194!F (9 !C) when using it with a programming
control.
4. For high temperature installations, use moisture-resis-
tant No. 14 wire, selected for a temperature rating above the
maximum operating temperature.
5. All models have a terminal block inside the cover (Fig.
3 and 4) and a 7/8 in. (22.2 mm) hole in one side for 1/2 in.
conduit, cable, or wires. Remove the front cover by loosen-
ing the screw at the bottom of the main scale.
6. Refer to Fig. 5 through 9 for typical hookups. Follow
the burner or boiler manufacturer’s wiring diagram if pro-
vided .
7. Make sure the loads do not exceed the Switch Contact
Ratings in the Specifications section.
8. Replace the front cover when wiring is completed.
Fig. 3—L404 terminal blocks and internal
schematics.
RISE
BREAKS ON
PRESSURE RISE
TO SETPOINT
RISE RISE
R
R
R
W
W
W
B
B
B
L404A,C L404B,D L404F
(SNAP-ACTING)
MAKES ON
PRESSURE RISE
TO SETPOINT
BREAKS R-B,
MAKES R-W ON
PRESSURE RISE
TO SETPOINT
M8941
Fig. 4—L404 terminal block and internal
schematic.
RISE
1
1
RISE
BB
R2
R1 W
W
JUMPER
SPDT SWITCH ACTION WITH JUMPER INSTA ED;
OTHERWISE, TWO ISO ATED SPST SWITCHES.
MAKES R1-W
BREAKS R2-B
ON PRESSURE RISE TO SETPOINT.
L604A L604L,M
M8935
R
Fig. 5—L404 used as a limit or as an operating
controller.
M8936
1
(HOT)
2
2
1
1
2
PROVIDE DISCONNECT MEANS AND OVER OAD PROTECTION
AS REQUIRED.
HIGH IMIT— 404A OR C BREAKS WHEN PRESSURE RISES
TO SETPOINT.
OW IMIT— 404B BREAKS WHEN PRESSURE FA S TO SETPOINT
MINUS DIFFERENTIA .
OPERATING CONTRO ER— 404A BREAKS WHEN PRESSURE RISES
TO SETPOINT, AND MAKES AGAIN WHEN PRESSURE FA S TO
SETPOINT MINUS DIFFERENTIA .
2
POWER
SUPP Y
F AME
SAFEGUARD
CONTRO ,
MOTOR, OR
OTHER OAD
SPST
CONTRO ER

76 -215 —1
L404A-D,F; L604A,L,M
INSTALLATION
Fig. 6—L404 with a low voltage relay.
M8939
1
(HOT)
2
2
1
1
2
PROVIDE DISCONNECT MEANS AND OVER OAD PROTECTION
AS REQUIRED.
BREAKS R TO B AND MAKES R TO W WHEN PRESSURE
RISES TO SETPOINT.
POWER
SUPP Y
SPDT
CONTRO ER
W
R
B
W1
R1
B1
1
2 M644B
INE VO TAGE
TWO-POSITION MOTOR
C OSED
( OW FIRE)
OPEN
(HIGH FIRE)
WHITE
RED
B UE
B ACK
B ACK
Fig. 8—L404F, L604A (with jumper installed) or
L604M, used as a low limit, with an alarm
circuit.
M8938
1
(HOT)
2
2
1
1
2
PROVIDE DISCONNECT MEANS AND OVER OAD PROTECTION
AS REQUIRED.
BREAKS R TO B AND MAKES R TO W WHEN PRESSURE
RISES TO SETPOINT.
2
POWER
SUPP Y
F AME
SAFEGUARD
CONTRO ,
MOTOR, OR
OTHER OAD
SPDT
CONTRO ER
(HIGH IMIT)
W
R
B
A ARM
Fig. 9—L404F, or L604 with jumper installed,
controlling an M644B motor.
M8940
1
(HOT)
2
1
1
PROVIDE DISCONNECT MEANS AND OVER OAD PROTECTION
AS REQUIRED.
24 VO T
THERMOSTAT
OW VO TAGE RE AY 404
OAD
THERM
POWER
SUPP Y
1
2
Fig. 7—L404F, L604A (jumper installed) used
as a high limit, with an alarm circuit.
M8937
1
(HOT)
2
2
1
1
2
PROVIDE DISCONNECT MEANS AND OVER OAD PROTECTION
AS REQUIRED.
BREAKS R TO W AND MAKES R TO B WHEN PRESSURE
FA S TO SETPOINT MINUS DIFFERENTIA .
2
POWER
SUPP Y
F AME
SAFEGUARD
CONTRO ,
MOTOR, OR
OTHER OAD
SPDT
CONTRO ER
( OW IMIT)
W
R
B
A ARM

6 -215 —1 8
L404A-D,F; L604A,L,M
SETTING AND CHECKOUT
S TTING
In all models, the differential is subtractive from the
main scale set point. The upper operating point is deter-
mined by the main scale set point, while the lower operat-
ing point is determined by the main scale setting less the
differential setting. The L4 4F and L6 4A (with jumper
installed), L,M have spdt switching action. Operating points
are shown in Fig. 1 .
Fig. 10—L404 and L604 operating points.
main scale setpoint. They will not automatically return to
their former positions. To reset one of these controllers,
wait until the pressure falls to the set point minus the
differential (Fig. 1 ). Then depress the manual reset lever
(Fig. 11) and release it. The controller will not be reset until
you release the manual reset lever. This prevents the con-
troller from becoming an automatic-reset device if the reset
lever is stuck, held in, or tied down.
Fig. 11—Setting a Pressuretrol Controller.
Setting and Checkout
MAIN SCA E SETPOINT
(SWITCH BREAKS)
SUBTRACTIVE
DIFFERENTIA
DIFFERENTIA SETTING
(SWITCH MAKES)
PRESSURE
RISE
L404A,C
1
MAIN SCA E SETPOINT
(SWITCH MAKES)
SUBTRACTIVE
DIFFERENTIA
DIFFERENTIA SETTING
(SWITCH BREAKS)
PRESSURE
RISE
L404B,D
1
MAIN SCA E SETPOINT
(BREAKS R-B, MAKES R-W)
SUBTRACTIVE
DIFFERENTIA
DIFFERENTIA SETTING
(MAKES R-B, BREAKS R-W)
PRESSURE
RISE
L404F;
L604L,M
1
2
MAIN SCA E SETPOINT
(MAKES R1-W, BREAKS R2-B)
SUBTRACTIVE
DIFFERENTIA
DIFFERENTIA SETTING
(BREAKS R1-W, MAKES R2-B)
PRESSURE
RISE
L604A
1
2
404C,D AND 604 MANUA RESET MODE S HAVE A SMA , FIXED
DIFFERENTIA . THEY CAN BE MANUA Y RESET WHEN THE PRESSURE
FA S TO THE MAIN SCA E SETPOINT MINUS THE DIFFERENTIA .
604M HAS A SMA , FIXED DIFFERENTIA OF 3.5 PSI (0.25 kg/cm2)
OR 24.1 kPa.) M8942
Adjust the main scale set point for the desired operating
pressure by turning the main scale adjusting screw (Fig. 11)
on the top of the case until the main scale setting indicator
is at the desired value. On an L4 4A,B,F with a 5 to 15 psi
(.3 to 1 .3 kg/cm2 [34 to 1 34 kPa]) operating range, or an
L6 4A, adjust the differential setting by turning the dif-
ferential adjusting screw (Fig. 11) until the differential
setting indicator is at the desired value. L4 4C,D and
L6 4L are manual reset models: see the next paragraph.
The L6 4M has a fixed differential. The scaleplates are
marked psi and kg/cm2.
Trip-Free Manual Reset Feature
(L404C,D and L604L only)
The L4 4C breaks, the L4 4D makes, and the L6 4L
makes R-W and breaks R-B when the pressure rises to the
MERCURY
SWITCH
DIFF. MAIN
PSI
12
10
8
6
4
2.1
.3
.5
.7
.8
.6
.4
.2
0
.5
120
10
30
40
50
3.5
3
2.5
2
1.5
0
DIAPHRAGM
ASSEMB Y EVE ING
INDICATOR
POINTER
INDEX
MARK
MANUA
RESET
EVER
MAIN SCA E
ADJUSTING
SCREW
DIFFERENTIA
ADJUSTING
SCREW
SCA EP ATES
DIFFERENTIA
SETTING
INDICATOR
MAIN SCA E
SETTING
INDICATOR
ADJUSTAB E DIFFERENTIA ON THE 404A,B,F; 404 WITH A 5 TO
150 PSI (0.34 TO 10.3 kg/cm2 [34 TO 134 kPa] OPERATING RANGE;
AND 604A MODE S ON Y.
TRIP-FREE MANUA RESET EVER ON THE 404C,D AND 604
MODE S ON Y. M8943
1
2
1
2
CH CKOUT
After the controller has is installed, wired, and set, test it
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 set point
is lowered.
Also check the make and break points of the controller.
If they do not agree with a separate, accurately calibrated
pressure gauge, a slight adjustment of the scaleplate(s) may
be necessary.
Use accurate pressure testing equipment when checking
out the controller. Do not rely on inexpensive gauges. The
controllers are carefully calibrated at the factory.

96 -215 —1
L404A-D,F; L604A,L,M
SETTING AND CHECKOUT
Boiler Installation
If the controller is being used on a boiler installation, test
it as follows:
1. Note the boiler pressure by checking the boiler pres-
sure gauge. (To perform this test properly, the boiler should
have a pressure reading near the middle of the controller’s
main scale range.)
2. Turn the main scale adjusting screw (Fig. 11) until the
main scale setting indicator on the controller corresponds to
the boiler pressure gauge reading.
3. The L4 4A or C should break the control circuit(s)
automatically when the boiler pressure gauge reading equals
or slightly exceeds the controller setting.
The L4 4B or D should make the circuit under the same
circumstances.
The L4 4F; L6 4L,M should make the R-W circuit and
break the R-B circuit under the same circumstances.
The L6 4A should make the R1-W circuit and break the
R2-B circuit under the same circumstances.
4. If the controller is operating properly, turn the main
scale adjusting screw (Fig. 11) until the main scale setting
indicator is at the desired set point.
If a Controller Seems to Operate Improperly
If the controller is suspected of operating improperly, it
may be further checked as follows (Fig. 12):
1. Disconnect all power to the controller, loosen the
cover screw, and remove the cover.
2. Disconnect the wires from the controller.
3. Connect an ohmmeter between the switch terminals.
4. Lower the set point of the controller (simulating a
pressure increase) through a range greater than the differen-
tial. The switch should either make or break, depending on
the model of the controller. (An L4 4A or C should break, an
L4 4B or D should make, an L4 4F; L6 4L,M should break
R-B and make R-W, and an L6 4A should break R2-B and
make R1-W.) If it makes, the ohmmeter reads zero; if it
breaks, the ohmmeter reads infinity.
5. Raise the set point of the controller (simulating a
pressure decrease) through a range greater than the differen-
tial. The switch should break or make, just the opposite of its
action in step 4 (except for the L4 4C,D and L6 4L manual
reset models).
NOTE: An approximation of the differential can be made by
observing the change in set point required for a resistance
change from zero to infinity.
6. If the controller operates improperly, replace it.
7. When the controller is operating properly, reconnect
the wires to the terminal block, replace the cover and tighten
the cover screw, and reconnect the power.
CAUTION
Do not put the system into service until you have
satisfactorily completed all applicable tests de-
scribed in this Checkout section, in the Checkout
section of the applicable instructions for the flame
safeguard control, and any others required by the
burner and boiler manufacturers.
Fig. 12—Checking controller operation using
an ohmmeter.
W
B
DIFF. MAIN
PSI
12
10
8
6
4
2.1
.3
.5
.7
.8
.6
.4
.2 .5
1
3.5
3
2.5
2
1.5
0
KG
CM 2 KG
CM 2
DIFF. IS
SUBTRACTIVE
0
20
10
30
40
50
PSI
R1 R2
M8944
INPUT OUTPUT
ZERO
ADJ
0W
R
B
SETPOINT
DECREASE
MAIN SCA E
ADJUSTING SCREW
ZERO OHMS
(INFINITY WHEN R-B BREAKS)
OHMMETER
1 AN 604, WITH JUMPER INSTA ED BETWEEN R1 AND R2, IS SHOWN;
AN 404F OPERATES SIMI AR Y (SPDT SWITCHING). AN 404A, B, C
OR D HAS ON Y TWO TERMINA S (SPST SWITCHING); AN 404A
OR C BREAKS AND 404B OR D MAKES WHEN THE SETPOINT IS
DECREASED FAR ENOUGH.
1
DIFFERENTIA
SETTING
INDICATOR
MAIN SCA E
SETTING
INDICATOR

6 -215 —1 1
L404A-D,F; L604A,L,M
SERVICE INFORMATION
Service Information
CALIBRATION
The controller was carefully calibrated during manufac-
turing and should not require recalibration. Most calibra-
tion errors are caused by improper leveling. The controller
should be level when the pointer on the leveling indicator is
directly over the index mark (Fig. 11). In some cases, the
leveling indicator may not be accurate enough. The pointer
may be over the index mark, but the controller still may not
be operating within the tolerance of its scale setting. In this
case, carefully bend the steam trap (siphon loop) until the
controller switches properly.
MAINT NANC
The cover of the controller should be in place at all times
to protect the internal components from dirt, dust, and
physical damage. Routine maintenance should consist of
occasional inspection and blowing or brushing away any
accumulated dirt and dust. To ensure proper functioning of
the controller at all times, perform an operational check of
the entire system during routine maintenance checks.

11 6 -215 —1

6 -215 —1 12
Home and Building Control Home and Building Control Helping You Cont ol You Wo ld
Honeywell Inc. Honeywell Limited—Honeywell Limitée
1985 Douglas Drive North 74 Ellesmere Road
Golden Valley, MN 55422 Scarborough, Ontario
M1P 2V9
Printed in U.S.A. www.honeywell.com/bbc