Honeywell L4006 Installation Manual

L4006A,B,E,H

WARNING

Aquastat® Controllers

APPLICATION

These boiler-mounted, immersion type controllers
operate in response to temperature changes in hydronic
heating systems.

L4006A breaks the circuit on a temperature rise to the
control setting. It is used for high limit or low limit control.
When used as a controller or as a low limit, a separate
high limit must be used.

L4006B makes the circuit on a temperature rise. It is
used as a circulator controller, delaying circulator
operation when boiler water temperature is below the
control setting.

L4006E,H includes a trip-free manual reset switch.
These models are designed to break the control circuit
whenever the temperature of the controlled medium
reaches the high limit setting. A reset button on the front
of the case must be pressed to re-establish the control
circuit. L4006H also includes bracket and clamp for
surface mounting on pipe or tank.

A plastic bag of heat-conductive compound is included
with the L4006A,B,E Aquastat® Controllers for use when
the sensing bulb is inserted into a well designed for a
large bulb than the one used on the L4006A,B,E. A
124904 Well Adapter, for use on old wells that do not fit
the L4006A,B,E immersion well clamp, can be ordered;
see form 68-0040, Wells and Fittings for Temperature
Controllers. A setting stop is included to prevent setting
above a desired temperature on limit.

If a well adapter or other accessories are needed, refer to
form 68-0040, Wells and Fittings for Temperature
Controllers, for part numbers and ordering information.

INSTALLATION

When 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.

Installing Immersion Well Models (L4006A,B,E)

IMPORTANT

NOTE: Some models have an adjustable capillary

Follow the boiler manufacturer instructions, if available;
otherwise, proceed as follows.

INSTALLATION INSTRUCTIONS

3. Installer must be a trained, experienced service
technician.

4. After installation is complete, check out product
operation as provided in these instructions.

Electrical Shock Hazard.
Can cause serious injury, death or equipment
damage.

Disconnect the power supply before beginning
installation to prevent electrical shock or
equipment damage.

Obtain the best thermal response with a well
that snugly fits the sensing bulb. The bulb
should be inserted until it rests against the
bottom of the well. Use a well of correct length
and bend the tubing, if necessary, to provide
enough force to hold the bulb against the
bottom of the well. Do not make a sharp bend in
the tubing. A sharp bend can produce a break in
the tubing and cause a loss of fill. This condition
will cause the high and low limit controls to be
made continuously.

If the well is not a snug fit on the bulb, use the
heat-conductive compound as follows. Fold the
plastic bag of compound lengthwise and twist
gently. Snip the end of the bag and insert into
the well. Slowly pull out the bag while squeezing
firmly to distribute the compound evenly in the
well. Insert the bulb into the well. Bend the
tubing, if necessary, to provide force to hold the
bulb against the bottom of the well and to hold
the out end of the bulb in firm contact with the
side of the well. Wipe off any excess compound.

tubing length to 3 inches (76 mm). In these
models, pull out extra tubing from inside the
case, if needed.

60-0915-5

L4006A,B,E,H AQUASTAT® CONTROLLERS

1. Remove the old control.

2. Refer to the cover insert of the old control to identify

and tag each lead as it is disconnected.

3. Leave the old well in place if it is suitable.

If Well is Otherwise Suitable But Does Not Fit The
L4006 Immersion Well Clamp

Use a 124904 Well Adapter (order separately, see form
68-0040) to secure the L4006 to the old well. The adapter
has a flange at one end for fastening the L4066 adapter
clamp.

1. Loosen, but do not remove, the two adapter clamp
screws (see Fig. 1).

2. Slide the adapter onto the capillary and short tube;
see Fig. 2 inset.

3. Make sure the flanged end of the adapter fits into
the hole in the case. Position the adapter well clamp
snugly over the flange on the adapter, then tighten
the clamp screws.

4. Insert the bulb into the well, as shown in Fig. 2. If
necessary, use the heat-conductive compound as
instructed in the IMPORTANT statement on page 1.

5. Tighten the setscrew (if one is present in the old
well spud) against the adapter.

CONTROLLER
CASE

ADAPTER
CLAMP

ADAPTER

1

BOILER

IMMERSION
WELL SPUD

SETPOINT
INDICATING DIAL

DIFFERENTIAL
ADJUSTMENT
WHEEL

ADAPTER CLAMP
SCREWS

1

MODELS WITH FIXED DIFFERENBTIALS DO NOT INCLUDE
ADJUSTING WHEEL.

2

VERTICALLY MOUNTED IMMERSION WELL IS ATTACHED
TO THE BOTTOM OF THE CASE.

Fig. 1. Internal view of L4006A,B with horizontal well.

L4006E is the same with reset button added.

ADAPTER
CLAMP

ADAPTER

OLD IMMERSION
WELL ASSEMBLY

SENSING
BULB

2

1

IMMERSION
WELL

M4679

BACK OF
CASE

(C)

2

CAPILLARY
TUBE

SETSCREW

1

SLIGHTLY BEND IN TUBES SHOULD HOLD BULB IN GOOD THERMAL CONTACT WITH THE WELL AT TWO OPPOSITE POINTS, AS IN (A) AND (B).

2

ASSURE THAT TUBES FIT FREELY IN ADAPTER SO THAT TENSION OF THE CAPILLARY TUBE AT POINT (C)
HOLDS THE SENSING BULB IN GOOD THERMAL CONTACT WITH THE BOTTOM OF WELL AT POINT (D).

SHORT TUBE
FITS IN CENTRAL
RECESS OF
ADAPTER

(A)

HEAT-CONDUCTIVE COMPOUND

Fig. 2. Bulb in immersion well and use of adapter.

If the Old Well Is Unsuitable.

1. Drain the system and remove the well.

2. Select a new well from form 68-0040 (order well

separately).

3. Install the new well, refill the system and check for
leaks.

60-0915—5 2

4. Loosen, but do not remove, the two adapter clamp
screws (Fig. 1).

5. Insert the sensing bulb into the well until it bottoms
as show in Fig. 2. Add heat-conductive compound,
if necessary, as instructed in the IMPORTANT
statement on page 1.

M4678

(D)

(B)

6. Make sure the end of the well fits into the hole in the

WARNING

A

case. Position the immersion well clamp snugly
over the well flange and tighten the clamp screw
securely.

Mounting Surface Mount Model (L4006H)

The L4006H is designed for surface mounting on piping or
tank and can be mounted in any position.

When mounting the L4006H on piping, the pipe should be
1 in. (25 mm) diameter or larger for accurate temperature
sensing.

1. Remove any insulation from the pipe.

2. Thoroughly scrape off all scale, rust or paint.

3. Mount controller as shown in Fig. 3 using adjustable

12 in. (294 mm) pipe strap furnished.

When mounting the L4006H on a tank, use a pipe strap of
appropriate length, approximately 6-10 ft (17.6- 29.4m) for
the tank (not provided). Fit the pipe strap through the slot
in the mounting bracket. See Fig. 3.

Wiring

L4006A,B,E,H AQUASTAT® CONTROLLERS

ENCLOSED
SENSING BULB

PIPE

12 IN.

DJUSTABLE
PIPE
STRAP

AQUASTAT
CONTROLLER CASE

Fig. 3. Mount L4006H directly on surface.

MOUNTING
BRACKET

M8771A

Electrical Shock Hazard.
Can cause serious injury, death or equipment
damage.

Disconnect power supply before connecting wiring
to avoid electrical shock or equipment damage.

All wiring must comply with local codes and ordinances
regarding wire size, insulation, enclosure, etc. See Fig. 4
and 5 for typical diagrams of Aquastat® Controllers used
in heating systems.

Use these Aquastat Controllers with copper wire only.

24 VOLT
THERMOSTAT

LOW WATER
CUTOFF

2

L4006A OR
L4007A
LOW LIMIT
AQUASTAT¨
CONTROLLER

1

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROJECTION AS REQUIRED.

2

USE L4006E FOR MANUAL RESET.

Fig. 4. Typical hookup for gas-fired system with

domestic hot water.

GAS
VALV E

PRESSURE
CONTROL

PILOTSTAT¨
CONTROL

M2856

L1
(HOT)
L2

24 VOLT
THERMOSTAT

RA832A
SWITCHING RELAY

TT

XX

1

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND

1

OVERLOAD PROTECTION AS REQUIRED.

2

USE L4006E FOR MANUAL RESET.

Fig. 5. Hookup for oil-fired, summer-winter, hydronic

system with domestic hot water. This is typical where

control for domestic hot water is added, or where

each Aquastat Controller is mounted in a separate

2

1

4

L4006B OR L4007B
CIRCULATOR
AQUASTAT¨
CONTROLLER

2

L4006A OR L4007A LOW LIMIT
AQUASTAT¨ CONTROLLER

L1
(HOT)

CIRCULATOR

location.

1

L2

PROTECTORELAY¨
CONTROL

3 60-0915—5

L4006A OR L4007A
HIGH LIMIT
AQUASTAT¨
CONTROLLER

IGNITION

BURNER

M2855A

1

2

4

3

T

T