Submittal Sheet

L408J VAPORSTAT
®
CONTROLLERS
65-0287—01 4
IMPORTANT
1. Locate the controller where the ambient temperature
will not exceed 150°F (66°C).
2. Use pipe compound sparingly to avoid clogging the
hole in the pipe or diaphragm fitting.
3. Do not tighten the controller by hand by holding the
case.
Location and Mounting
When used with steam boilers, always mount the controller
above the water line in the boiler. A steam trap (siphon loop)
must always be connected between the controller and the
boiler (see Fig. 2) to prevent boiler scale and corrosive vapors
from attacking the diaphragm.
The controller can be mounted (1) alongside the pressure
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.
Make all pipe connections in accordance with approved
standards. When making pipe connections, use pipe
compound sparingly to seal the joints. Excess pipe compound
may 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 hexagonal
fitting. Do not tighten the controller by hand by holding the
case.
Mounting Alongside a Pressure Gauge
To mount the controller alongside a pressure gauge, 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. See Fig. 2.
Fig. 2. Steam trap mounting of L408J.
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
provided by the boiler manufacturer. Screw the controller
directly on the steam trap.
Mounting at a Remote Location
If there is excessive vibration at the boiler which may adversely
affect the operation of the controller, the controller should be
mounted 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 between the remote piping
and the controller.
WIRING
WARNING
Electrical Shock Hazard.
Can cause severe injury, death or property damage.
Disconnect the power supply before beginning wiring.
More than one disconnect may be required.
1. All wiring must comply with applicable electrical codes,
ordinances and regulations. Use NEC Class 1 (line
voltage) wiring.
2. For normal installations, use moisture-resistant NO. 14
wire suitable for at least 167°F (75°C) if you are using
the controller with a flame safeguard primary control or
at least 194°F (90°C) if you are using it with a
programming control.
3. For high temperature installations, use
moisture-resistant No. 14 wire, selected for a
temperature rating above the maximum operating
temperature.
4. Disconnect the power supply before beginning wiring to
prevent electrical shock and equipment damage.
5. All models have a terminal block inside the cover (see
Fig. 3) and a 7/8 in. (22 mm) hole in one side for 1/2 in.
(13 mm) conduit, cable or wires. Remove the front cover
by loosening the screw at the bottom of the main scale.
6. Refer to Fig. 4 through 6 for typical hookups. Follow the
burner or boiler manufacturer wiring diagram, if provided.
7. Make sure the loads do not exceed the Switch Contact
ratings in the Specifications section.
8. Replace the front cover when wiring is complete.
4-1/2 TO 5-1/2
(114.3 TO 139.7)
BOILER
STEAM TRAP
(SIPHON LOOP)
TEE
PRESSURE
GAUGE
PRESSURE
CONTROLLER
M23883
1
1
1/4 IN. PIPE WITH 1/4 - 18 NPT EXTERNAL THREADS
ON BOTH ENDS AND 2-1/4 IN. DIAMETER LOOP.