L4188A,B; L4189A,B; L6188A-C;
®
L6189A-C Aquastat Controllers
PRODUCT DATA
FEATURES
•
L4188 and L4189 provide spst switching for high and
low limit control.
•
L6188 and L6189 provide spst switching for low limit
and circulator control.
•
•
•
L4188, L6188 models are direct-mounted.
L4189, L6189 models are remote bulb.
Diaphragm-operated switch breaks on temperature
rise (spst and normally closed spdt contacts).
•
•
•
Compact controller case for application flexibility.
3/16 in. diameter bulb for faster response.
Remote Bulb with
Screwdriver Slot
All models available with or without setting knob.
Models without knob are adjusted with screwdriver.
•
•
Choice of manual or auto reset. Auto reset models
available with fixed or adjustable differential.
1/4 in. male quick-connects standard; combination
screw and 1/4 in. quick-connects available.
•
•
Field adjustable high or low limit stop available.
Bracket for surface mounting available on remote bulb
models.
•
•
Capillary on remote bulb models available in several
lengths.
Direct Mount with
Setting Knob
Immersion well with 1/2 in. NPT spud available as
accessory.
APPLICATION
®
Aquastat Controllers are bulb-type providing operating or
limit control of water temperature in hot water heating systems
and water heaters.
Contents
Application.........................................................................
Features ............................................................................
Specifications ....................................................................
Ordering Information .........................................................
Installation .........................................................................
Wiring ................................................................................
Operation...........................................................................
Adjustments.......................................................................
Checkout ...........................................................................
1
1
2
2
4
6
7
7
8
68-0061—1
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
Ambient Temperature Range: 32° to 158° F (0° to 70° C).
Dimensions: See Fig. 1.
Mounting: Must be mounted in an enclosure that meets local
electrical codes.
Sensing Bulb: Liquid-filled copper (See Fig. 1).
Direct: Unit mounts on immersion well at desired sensing
location.
Underwriters Laboratories Inc. Component Recognized:
File No. MP466, Guide No. MBPR.
Remote bulb: Sensing bulb is inserted into immersion well
at desired sensing location. Controller case mounts
behind remote panel with two self-tapping M4 or No. 8
sheetmetal screws (supplied). Optional mounting bracket
allows mounting on front of panel. Specify bracket when
ordering.
Canadian Standards Association Listed: File No. LR62051-1.
KNOB MODEL
2-11/16
(68)
19/32
(15)
1-1/4
(32)
11/16
1/2
(17)
(13)
7/16
(11)
3/16
(5)
19/32
(15)
5/8
(16)
1-7/8
(48)
1
HOLE FOR
UP TO NO. 10
SCREW
4 (101)
3/8
(9)
SEE
TABLE
1-7/8
(48)
1-7/8
(48)
SCREWDRIVER SLOT MODEL
SEE
4 (101)
TABLE
1-1/4
(32)
1/2
(13)
5/8
(16)
1-7/8
(48)
3/16
(5)
1-7/8
(48)
3/8
(9)
1-7/8
(48)
1-7/8
(48)
IMMERSION WELLS
INSULATION
INSERTION
OPTIONAL MOUNTING BRACKET
1
PART NO.
SPUD
INSULATION INSERTION
45900409-003B
45900409-009B
45900409-010B
1/2 in. BSPT
1/2 in. NPT
3/4 in. NPT
1 in.
3-1/2 in.
3 in.
1-1/2 in.
1-1/2 in.
3 in.
MODEL
CAPILLARY LENGTH
MOUNTING
DIRECT MOUNT
L4188, L5188
1-3/16 IN.
30 MM
USE IMMERSION WELLS SHOWN AT RIGHT
2-5/16 IN.
39-3/8 IN.
50 IN.
50 MM
1000 MM
1500 MM
2000 MM
REMOTE MOUNT
L4189, L5189
USE IMMERSION WELLS SHOWN AT RIGHT
OR CAPILLARY COMPRESSION FITTINGS
78-11/16 IN.
M25414
Fig. 1. Dimensions in in. [mm in brackets] of Aquastat Controller and Immersion Well.
3
68-0061—1
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
Accessories (order separately):
3. Refill the system. Check for and correct any leaks.
Capillary compression fittings.
USE MODERATE AMOUNT
OF PIPE COMPOUND
Part No. 104484A: 1/2 in. NPT spud.
Part No. 104484B: 3/4 in. NPT spud.
Immersion well: Pressure rating 255 psi [1760 kPa].
Part No. 45900409-003B: 1/2 in. BSPT spud, 1 in.
insulation, 3-1/2 in. insertion.
Part No. 45900409-009B: 1/2 in. NPT spud, 1-1/2 in.
insulation, 3 in. insertion.
LEAVE 2 END THREADS BARE
M25415
Part No. 45900409-010B: 3/4 in. NPT spud, 1-1/2 in.
insulation, 3 in. insertion.
Fig. 2. Use good Piping Practice when Installing
Immersion Well.
Optional Specifications (Specify when ordering):
•
Combination screw and 1/4 in. male quick-connect
terminals.
To Install Direct Mount Controller
•
•
High or low limit stop (models with knob only).
Mounting bracket (remote bulb models only).
1. Slide the sensing bulb all the way into the well. The metal
collar around the capillary should slip into the well spud.
2. Line up the case so the setting indicator is on top.
3. Tighten the setscrew in the well spud snugly against the
metal collar.
INSTALLATION
CONTROLLER
SETSCREW
SPUD
When Installing This Product...
1. Read these instructions carefully. Failure to follow them
could damage the product or cause a hazardous
condition.
WELL
2. Check the ratings given in the instructions and on the
product to make sure the product is suitable for your
application.
BULB
METAL
CAPILLARY
COLLAR
3. Installer must be a trained, experienced service
technician.
M25416
4. After installation is complete, check out product
operation as provided in these instructions.
Fig. 3. The Direct Mount Model is held in place by the
Setscrew in the Well Spud.
CAUTION
Disconnect power supply before wiring to avoid
electrical shock or equipment damage.
Terminal connections must be inside an enclosure
that meets local electrical codes.
To Mount Remote Bulb Controller
Insert Sensing Bulb in Well
1. Slide sensing bulb into well. Make sure bulb rests
against the bottom of the well. Don’t bend the capillary
where it connects to the bulb.
2. Hold bulb in place and tighten setscrew all the way
down. It won’t fit tight against the capillary, but it will keep
the bulb from sliding out.
Location
The equipment manufacturer generally provides a tapping for
insertion of the temperature controller sensing element. The
tapping should be located at a point where average system
temperature will be measured. Never locate the sensing
element close to a hot or cold water inlet or a steam coil, or
where the well’s pressure rating will be exceeded.
SETSCREW
SPUD
CAPILLARY
Turn off power and, if the system is filled, drain to a point below
the boiler tapping or wherever the sensing element is to be
located. If no tapping is provided, prepare one, properly
threaded, at the desired location.
SETSCREW
SPUD
WELL
BULB
If this is a remote bulb unit, the controller case can be mounted
in a panel or, with the optional bracket, on any flat surface.
Choose a location within reach of the sensing element. Allow
for gradual bends and some slack in the capillary.
CAPILLARY
M25417
Fig. 4. The Setscrew keeps the Remote Sensing Bulb in
the Well.
Mount the Immersion Well
1. Coat the well threads with a moderate amount of pipe
®
dope, leaving two end threads bare. Teflon tape may
also be used.
2. Screw the immersion well into the tapping and tighten
securely.
68-0061—1
4
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
4. ADJUSTABLE DIFFERENTIAL MODELS ONLY: Set
Mounting Behind Panel-Controller with Knob
differential. See Adjustment and Checkout section.
5. Using setting indicator as a template, mark and drill
holes in the panel for the mounting screws and for the
knob shaft.
6. Mount the controller behind, and the setting indicator in
front of, the panel using the two screws removed earlier
(See Fig. 5).
7. MODELS WITH TEMPERATURE LIMIT STOP ONLY:
Adjust to desired setting, as described under “To Set
Temperature Limit Stop,” page 8.
NOTE: The panel can be up to 5/64 in. thick.
1. Uncoil capillary, starting at bulb. Avoid sharp bends or
kinks in the capillary. Leave excess capillary loosely
coiled below controller case.
2. Remove the setting knob by pulling straight off.
3. Remove the two screws that hold the setting indicator in
place and remove the setting indicator (See Fig. 5).
8. Replace knob on shaft.
SETTING
INDICATOR
CONTROLLER
PANEL
NO. 8
(MAX. 5/64 IN. THICK)
MOUNTING
SCREWS (2)
KNOB
M25418
Fig. 5. The Mounting Screws hold the Setting Indicator and Controller in place.
Mounting Behind Panel-Controller with Screwdriver Slot
1. Mark and drill three holes in the panel, using the tem-
plate in Fig. 6 as a guide.
2. MANUAL RESET MODELS ONLY: Drill a fourth hole to
make the manual reset button accessible.
3. ADJUSTABLE DIFFERENTIAL MODELS ONLY: Drill a
hole for the differential dial, if desired, Set the differential.
See Adjustment and Checkout section.
4. Hold controller against back of panel with terminals
pointed down and fasten with two No. 8 sheetmetal
screws (not supplied) (Refer to Fig. 6).
5
68-0061—1
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
MOUNTING TEMPLATE
NO. 10
3/4
SHEETMETAL
SCREWS (2)
(OBTAIN LOCALLY)
3/16
5/16
3/16
1
1
PANEL
2
MOUNTING
BRACKET
5/8
3/16
3
1
2
DRILL 2 MOUNTING SCREW HOLES.
DRILL HOLE FOR SLOTTED SHAFT. USE SMALL HOLE FOR SHAFT
ONLY; LARGE HOLE SHAFT PLUS SETTING SCALE.
3
DRILL SMALL HOLE FOR MODEL WITH MANUAL RESET BUTTON OR
LARGE HOLE FOR MODEL WITH DIFFERENTIAL ADJUSTMENT.
CONTROLLER
CAPILLARY
CONTROLLER
M25420
SLOTTED
SHAFT
Fig. 7. The Controller with Bracket Mounts on the Front of
the Panel.
WIRING
All wiring must comply with applicable codes and ordinances,
Disconnect power before beginning wiring.
MANUAL
RESET
BUTTON
NO. 8
MOUNTING SCREWS (2)
(OBTAIN LOCALLY)
Connect as shown in equipment manufacturer’s instructions, if
provided. Otherwise, use the typical hookups shown
(See Fig. 8) (refer to Figures 9 and 10).
PANEL
M25419
24V
Fig. 6. Drill holes in the Panel as shown.
THERMOSTAT
Mounting on Panel-Controller with Bracket
1. Using controller bracket as a template, mark and drill two
holes in the panel.
LOW WATER
CUTOFF
2. Mount controller with terminals down.
3. Run capillary neatly along panel, avoiding sharp bends
and interference with other components on the panel.
4. MODELS WITH TEMPERATURE LIMIT STOP ONLY:
Adjust to desired setting, as described under “To Set
Temperature Limit Stop,” page 8.
L4188.9
PRESSURE
L4188.9
LOW LIMIT
CONTROLLER
HIGH LIMIT
2
L1
(HOT)
L2
1
TH-TR
24V
GAS VALVE
TH
TR
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
USE L6188.9C (C-1 CONTACTS) IF MANUAL RESET IS REQUIRED.
M25421
Fig. 8. Low and High Limit Application on a Gas-Fired
System with Domestic Hot Water.
68-0061—1
6
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
OPERATION
24V THERMOSTAT
As the liquid filing the sensing bulb and capillary expands and
contracts, it moves a diaphragm. Movement of the diaphragm
is transferred by a lever to the snap-acting switch in the
controller.
RELAY CENTER
L1
R
G
(HOT)
High or Low Limit Action (L4188, L4189)
PROTECTORELAY
CONTROL
L2
The normally closed C-1 contacts open on temperature rise to
the set point, shutting off power to the controlled circuit. On
auto recycle models, the switch closes C-1 after the
temperature falls past the set point and through the differential
(See Fig. 11).
2
HIGH LIMIT
BLACK
BURNER MOTOR
3
LOW LIMIT
1
ORANGE
C
2
CIRCULATOR
MOTOR
Low Limit/Circulator Action (L6188, L6189)
CIRCULATOR
The low limit is connected to the normally closed C-1 contacts,
and the circulator to the normally open C-2 contacts. As long
as the temperature at the sensing bulb is above set point, the
circulator runs. If sensing bulb temperature falls past the set
point and through the differential, the switch breaks C-2 to turn
off the circulator, and makes C-1 to turn on the burner. When
the temperature rises to the set point, C-2 makes to turn on the
circulator, and C-1 breaks to turn off the burner.
IGNITION
WHITE
T
T
On manual reset models, the reset button must be pushed
before contacts C-1 will close (See Fig. 11).
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2
3
L4188 OR L4189 USED AS HIGH LIMIT.
TEMPERATURE
SETTING
L6188 OR L6189 USED AS LOW LIMIT/CIRCULATOR CONTROLLER.
M25422
SCALE
L4188.9
L6188.9
HIGH OR LOW
LIMIT
LOW LIMIT/
CIRCULATOR
220 F
Fig. 9. High Limit and Low Limit/Circulator Application in
an Oil-Fired Hydronic System with domestic hot water.
2
SET POINT
SET POINT
MANUAL
C
1
C
24V
1
RESET
THERMOSTAT
1
BREAKS
MAKES C-1
C-1 BREAKS
C-2 MAKES
L1 L2
DIFFERENTIAL
2
1
(HOT)
SWITCHING RELAY
AUTO
RA832A
RECYCLE
L4188.9
C
HIGH LIMIT
2
T
X
T
2
1
SET POINT
BLACK
C
1
LESS
C
1
DIFFER-
ENTIAL
MAKES
C-1 MAKES
WHITE
C-2 BREAKS
IGNITION
X
4
ORANGE
L4188.9
CIRCULATOR
100 F
M25424
L4188.9
T
T
LOW LIMIT
CIRCULATOR BURNER
Fig. 11. Aquastat Controller Switch Action on Temperature
Change.
PROTECTORELAY
CONTROL
LINE VOLTAGE
LOW VOLTAGE
1
PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS
REQUIRED.
ADJUSTMENTS
M25423
Fig. 10. High Limit and Separate Low Limit and Circulator
Application in an Oil-Fired Hydronic System with
Domestic Hot Water.
To Set Temperature
KNOB MODELS
Line up the desired temperature setting with the temperature
setting indicator behind the knob.
SCREWDRIVER SLOT MODELS
Line up the pointer on the shaft with the desired temperature
setting printed on the case.
7
68-0061—1
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
To Set Adjustable Differential (if provided)
Use a screwdriver to turn the differential dial until the slot
molded into the case lines up with the desired degrees of
differential.
AJUST LIMIT STOP
LIFT AND PUSH
TO CHANGE LIMIT
SETTING
CONTROLLER
LIMIT STOP
POINTER
KNOB
DIFFERENTIAL
ADJUSTMENT
DIAL
REPLACE KNOB ON SHAFT
SETTING
INDICATOR
M25425
SETTING INDICATOR:
LIMIT STOP MUST
BE ON RIGHT SIDE OF
SETTING INDICATOR FOR
HIGH LIMIT; ON LEFT
SIDE FOR LOW LIMIT
Fig. 12. Twist the Screwdriver Slightly to turn the
Differential Dial.
To Set Temperature Limit Stop (if provided)
SHAFT
CAUTION
FOR LOW LIMIT STOP:
Follow these instructions carefully to avoid
placing the limit stop pointer on the wrong side of
the setting indicator. In a high limit application,
incorrect positioning of the pointer will cause
system operation above the limit stop setting,
potentially resulting in overheating or related
conditions.
TURN SHAFT
FULL COUNTERCLOCKWISE
(SHOWN) BEFORE
REPLACING KNOB.
KNOB
FOR HIGH LIMIT STOP:
TURN SHAFT
FULL CLOCKWISE
BEFORE REPLACING
KNOB.
M25426
Fig. 13. Adjust the Limit Stop with a Screwdriver and
check Orientation when Replacing Knob on Shaft.
•
•
Remove the knob.
Turn the controller shaft all the way counterclockwise
when setting a high limit. Turn it all the way
clockwise
when setting a low limit.
CHECKOUT
•
•
Find the metal limit stop on the back of the knob.
Lift the limit stop slightly with a pencil or screwdriver and
push to move to desired setting.
Read the setting from the front of the knob.
Place the knob on the shaft.
Turn the knob to make sure it: (1) turns through the desired
adjustment range, and (2) stops at the limit setting.
DO NOT FORCE.
Turn the system on and observe it through several cycles to
make sure the controller operates as desired.
•
•
•
•
Return knob to desired setting.
Teflon® is a registered trademark for E.I. Du Pont De Nemours and Company.
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Toronto, Ontario M1V 4Z9
® U.S. Registered Trademark
© 2007 Honeywell International Inc.
68-0061—1 J.I. Rev. 10-07
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