L4031A,C POOL HEATER AQUASTAT® CONTROLLER
60-2107—5
3
Optional Specifications:
L4031A:
—Pool control dial marked WARMER-COOLER.
—High limit capillary exiting from top or bottom of case.
—Pool control range: 53°F to 107°F (12°C to 42°C),
100°F to 240°F (38°C to 116°C).
—Factory-set pool control limits set at 115°F, 180°F, and
200°F (46°C, 82°C, and 93°C).
—5°F (3°C) differential on pool control.
—Adjustable differential on high limit control.
—Factory high limit stops set at 140°F, 145°F, 180°F,
195°F, 200°F, and 210°F (60°C, 63°C, 82°C, 91°C,
93°C, and 99°C).
—Capillary lengths available at 16-1/2 (high limit only),
18, 30 (pool control only), 33, 40, and 96 in. (419, 457,
762, 838, 1016, and 2438 mm).
—Case marked “Tankstat.”
—No openings in cover.
— Less dial stops on pool control or both sides.
—No opening over high limit dial.
—With adjusting knob on pool control; less jumper.
L4031C:
—Factory high limit stop set at 250°F (121°C).
NOTE: Not all combinations of options are available. For
information, contact your Honeywell Sales
Representative or TRADELINE® Dealer.

When Installing this Product…

Read these instructions carefully. Failure to follow them
could damage the product or cause a hazardous
condition.
Check the ratings given in the instructions and on the
product to make sure the product is suitable for your
application.
Installer must be a trained, experienced service
technician.
After installation is complete, check out product
operation as provided in these instructions.
CAUTION
Disconnect power supply before beginning installation
to prevent electrical shock or equipment damage.
The L4031 can be mounted either vertically or horizontally on
a wall or panel, or directly on a tank. This device can be
installed with the case and bulbs as far apart as the tubing
permits. In all cases, the equipment manufacturer directions
should be followed, if available. If not, follow the general
instructions in the Location section.

Location

1. Locate the high limit bulb in the hot water outlet header
of the heater. Locate the pool control bulb in the return
water header of the heater.
2. Uncoil no more tubing than needed. Sharp or repeated
bending of the tubing can cause damage.
3. If the tubing is subjected to vibration, protect it against
wear when it comes in contact with another surface.

Mounting

1. Remove the cover by loosening the cover screw on the
lower front of the controller.
2. Fasten the case to a convenient wall or panel with
screws through the three mounting holes in the back of
the case.
3. Replace cover.

To Install Remote Bulb (Order Fittings or

Wells Separately)

NOTE: Bulb must be bottomed in well for correct response.
Using Bulb Compression Fitting (Fig. 2)
1. Screw the fitting into boiler or pipe tapping.
2. Slide sealing washer onto bulb.
3. Insert bulb into boiler fitting until bulb bottoms.
4. Slide split sleeve into fitting.
5. Place clamps A and B on assembly so sleeve is drawn
into fitting when screws are tightened.
NOTE: Make sure that nub on clamp A engages space
between sleeve and clamp.
6. Tighten clamp screws evenly.
FRONT VIEWSIDE VIEW
3/8 (10) DIA.
11/16
(17)
4-1/2
(114)
5-7/8
(149)
2-1/4 (57) 3-3/8 (86)
4-1/8 (105)
M4537
Fig. 1. Dimensions of L4031 in in. (mm).

INSTALLATION

WARNING
CAN CAUSE PROPERTY DAMAGE,
SEVERE INJURY OR DEATH.
This product is intended for use only in systems with a
pressure relief valve.