White Rodgers 770-1 - Manual

WHITE-RODGERS
- INSTRUCTIONS -
TYPE 770-1
AIR SWITCH
With SPDT Switch Action
(Responds to Positive, Negative,
or Differential Pressure)
The Type 770-1 has a SPDT switch that can be actuated by a positive pressure,
negative pressure, or a differential of pressure. These two features, plus its
field adjustable "operating range", give this control unmatched versatility on a
wide variety of applications, some of which are shown below.
TYPICAL APPLICATIONS
POWER HUMIDIFIERS
Switch permits unit to operate
whenever there is proper air move­
ment.
PROCESS DRYING
Switch monitors negative pressure
to stop conveyor or process, and
provides alarm signal on fan failure.
Ideal for bulk chemicals, food
processing, grain drying.
0
ELECTRONIC AIR CLEANERS
Switch permits power to cleaner
whenever blower of system is oper­
ating.
REFRIGERATION EQUIPMENT
Switch responds to pressure drop
across refrigeration coils to signal
alarm condition or automatically ini­
tiate or terminate defrost cycle.
NATURAL DRAFT BOILERS
Switch signals insufficient draft,
provides safety limit to stop firing
on lack of draft, starts again on
sufficient draft.
GAS-FIRED UNITS
Switch proves sufficient air flow be­
fore permitting gas valve to open
and ignition to occur.
- 0
-
INDUCED DRAFT BOILERS
Proves operation of I.D. fan by
sampling draft or air flow.
Shuts off firing equipment on fan
failure.
DUCT STRIP HEATERS
Switch proves air movement across
heaters by positive pressure in front
of heater. Turns off heater to pre­
vent burn-out on insufficient air
flow.
FORCED DRAFT BOILERS
Proves operation of blower by
sampling positive or negative pres­
sures for firing control and safety.
LEGEND
Negative Pressure
Positive Pressure
Pressure Differential
Pressure Sample Line
-SPECIFICATIONS-
ELECTRICAL RATING
15 AMP 125/250/277 VAC NT.
1/4 HP 125 VAC.
1/2 HP 250 VAC.
ELECTRICAL SWITCH
Single pole, double
throw snap action switch
CONTROL SET POINT
Adjustable
FIELD ADJUSTABLE
On pressure rise at .05
to 12" w.c.
CONDUIT OPENING
7/8" diameter opening
accepts 1/2" conduit
RECOMMENDED OPERATING POSITION
Diaphragm vertical
OPERATING TEMPERATURE RANGE
-40 to 180° F.
SAMPLE LINE CONNECTORS
Male externally threaded 7/16"-24
UNS 2 A thread complete with nut
and self aligning ferrule.
SAMPLE LINE CONNECTIONS
Connectors will accept 1/4" O.D.
rigid or semi rigid tubing. Slip
on tubing adaptors optional.
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123
IsMIERSaN
®
Printed in U.S.A.
PART No. 37-4898A
Replaces 37-4395
9110
4324
Rev.B