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L408J controlling a series 61 Motor (Modutrol).
L408J controller
R
B
W
2)
L1
(hot)
L2
power supply
1)
1) Provide disconnect means and overload
protection as required.
2) Transformer may be internal or external to
motor.
9 ADJUstMent
In all models, the differential is subtractive from the
main scale setpoint. The upper operating point is
determined by the main scale setpoint, while the
lower operating point is determined by the main
scale setting less the differential setting. Operating
points, see below.
R–W
B
Control
set point
A
B
B–R W
switch action on
pressure rise
indicates closed switch contacts
Operation of switch on pressure rise and fall
1 Adjust the main scale setpoint for the desired
operating pressure by turning the main scale
adjusting screw on the top of the case until the
main scale setting indicator is at the desired
value.
Series 61 motor
R
W
T1
B
T2
B R–W
Differential
(adjustable)
W
B–R
switch action on
pressure fall
2 Adjust the differential setting by turning the
differential adjusting screw until the differential
setting indicator is at the desired value.
➔ The scales are marked in psi and kPa.
10 test 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
pressure gauge.
➔ To perform this test properly, the boiler should
have a pressure reading near the middle of the
controller main scale range.
2 Turn the main scale adjusting screw (see Fig. 8)
until the main scale setting indicator on the
C
controller corresponds to the boiler pressure
gauge reading.
➔ The L408J should make the R-W and break the
R-B circuit automatically when the boiler pres-
sure gauge reading equals or slightly exceeds
the controller setting.
3 If the controller is operating properly, turn the
main scale adjusting screw (see Fig. 8) until the
main scale setting indicator is at the desired
setpoint
EN-5
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