L. Z. • Rev. 3-95 • ©Honeywell Inc. 1995
L404A-D,F; L604A,L,M
Pressuretrol
®
Controllers
CONTENTS
Specifications ................................................ 2
Ordering Information .................................... 2
Installation .................................................... 5
Setting and Checkout..................................... 8
Service Information ..................................... 10
L404 and L604 Pressuretrol
®
Controllers are
line voltage pressure controllers that provide oper-
ating control, automatic limit protection, or manual
reset limit protection for pressure systems of up to
300 psi (21.1 kg/cm
2
or 2068 kpa).
■ Screw adjustments made on top of case.
■ Scaleplates marked in English (psi) and Metric
(kg/cm
2
) units.
■ L404F models available with European enclosure,
British Standard Pipe Threads, ground screw, and
scaleplates marked in kg/cm
2
and either psi or kPa.
■ Clear plastic cover on case to observe pressure set-
tings and switch action.
■ Leveling indicator visible through cover.
■ Hexagonal fitting with 1/4-18 NPT internal threads
for direct mounting to 14026 Steam Trap (siphon
loop).
■ Surface mount is available using screws through
holes (knockouts) in case backing.
■ Can be used with steam, air, non-combustible gases,
or fluids non-corrosive to the pressure sensing ele-
ment.
■ Stainless steel diaphragm (except 300 psi [21.1 kg/
cm
2
(2068 kPa)] models) also allows use with am-
monia, oxygen, distilled water, and similar media.
■ L404B is recommended for supervision of atomiz-
ing medium pressure in oil burner systems.
■ Models are available with spst, spdt, or dpst switch-
ing and in variety of operating ranges.
■ Dustproof, trouble-free mercury switches (all mod-
els except L404F, which has snap-acting switch).
■ Automatic reset models have adjustable, subtractive
differential (except L604M).
■ Trip-free mechanism on manual reset models as-
sures that limit function of controller cannot be
defeated by jamming reset lever.
60-2150-10
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