Series 1620 – Single and Dual Pressure Switches
Specifications - Installation and Operating Instructions
Bulletin E-51
INSTALLATION
1. Switch is normally calibrated for mounting in the vertical position with pressure
and electrical connections pointing down. If other mounting is desired, it should be
specified when ordering.
2. Two lugs with 9/32˝ diameter holes, 180 degrees apart on an 8-1/4˝ diameter circle
are provided.
3. The location selected should be free from excessive vibration and ambient
temperatures should not be above 130°.
OPERATION
1. General – Differential pressure acting on the power diaphragm rotates a channel,
compressing a calibrated spring. The rotation of the channel actuates a snap switch
when the set-point is reached, opening one set of electrical contacts and closing the
other.
2. Pressure Connections – Two 1/8˝ NPT female connections are provided. Make
appropriate connections as follows:
A. Differential Pressure – Connect tubing from source of greater pressure to high
pressure port and from lower source to low pressure port.
B. Positive Pressure (above atmospheric) – Connect tubing from pressure source to
high pressure port. Leave low pressure port vented to atmosphere.
C. Negative Pressure (vacuum) – Connect tubing from vacuum source to low
pressure port. Leave high pressure port vented to atmosphere.
Note:
When installing switch per paragraphs B or C in dusty environments, we
recommend use of optional A-331 filter vent plug in the unused port. This will keep
excess dirt from collecting inside switch.
3. Electrical Connections – Make wire connections for normally open or normally
closed operation to appropriate screw terminals on snap switch.
ADJUSTMENT
1. If switch has been furnished pre-set, mount it vertically or horizontally as specified.
Shifting the position of the switch will alter the set point. Because the set-point may
shift in transit it should be checked before placing it in service.
2. The effective area of either side of the power diaphragm is changed by the effect of
the sealing diaphragm. Thus, the actuating differential pressure setting must be made
with the total pressure for the service intended imposed on both sides of the diaphragm.
For example, a switch set to close a circuit at a differential pressure increase to 1˝ of
water with a total pressure of 1 PSIG will vary from the 1˝ of water setting if the total
pressure is increased to 2 PSIG. Also, a two or three percent variation will be noted if
a switch set for vacuum or below atmospheric pressure is used for pressure or above
atmospheric pressure control.
3. To establish the set-point, use a manometer or pressure gage in an appropriate
range and of known accuracy. Apply pressure slowly to allow equalization in all
branches of the system. Keep tubing lengths as short as possible.
4. Model 1626 – The set-point is changed by turning the adjusting nut clockwise to
increase and counter-clockwise to decrease. Model 1627 – The set-point of snap
switch No. 2 is established first using the adjusting nut as with the 1626 series. Next,
set snap switch No. 1 by turning the adjusting screw under the switch roller. Recheck
switch No. 2 and correct as necessary. If switch No. 2 needs re-adjustment a final
check of switch No. 1 should be made. The settings of the two switches affect one
another and both should be checked any time either is changed.
MAINTENANCE
No unusual precautions are required. Care should be taken to keep the switch
reasonably dry and free from dust or dirt. No lubrication required.
CAUTION: For use with air or compatible gases only.
SPECIFICATIONS
Service:
Air and non-combustible,
compatible gases.
Wetted Materials:
Consult factory.
Temperature Limits:
-30 to 130°F
(-34.4 to 54.4°C).
Pressure Limits:
Max. 50 in. w.c. (12.44
kPa) continuous, 2 psig (13.79 kPa)
surge.
Switch Type:
1626, Single-pole double-
throw (SPDT); 1627, two Single-pole
double-throw (SPDT) .
Repeatability:
±1%.
Electrical Rating:
15 A @ 120-480 VAC,
60 Hz. Resistive, 1/8 HP @ 125 VAC,1/4
HP @ 250 VAC, 60 Hz.
Electrical Connections:
3 screw type,
common, normally open and normally
closed.
Process Connections:
1/8˝ female NPT.
Mounting Orientation:
Diaphragm in
vertical position. Consult factory for other
position orientations.
Set Point Adjustment:
Screw
Adjustment.
Weight:
Model 1626, 3 Ib, 9.8 oz (1.64
kg); Model 1627, 3 Ib, 11.8 oz (1.69 kg).
Agency Approvals:
CE.
MODEL 1626, ALSO MODEL 1627 DUAL SWITCHES: OPERATING
RANGES, DEAD BANDS AND RATINGS.
Model (1626
shown, 1627
similar)
Operating
Range
in w.c.
Approximate
Dead Band
Adj. Diff. Between
Set Points
(1627 only)
Min.
Max.
1626-1
1626-5
1626-10
1626-20
.15 to 1.5
.5 to 6.0
2.0 to 11
8.0 to 24
.10
.15
.25
.50
.20
.35
.65
1.20
0.5
1.2
2.3
5.0
Add –EXPL for explosion proof housing;
Add –WP for weather proof housing
Series 1620 Pressure Switch
2X Ø9/32 [Ø7.14]
MOUNTING HOLE
1/8 FEMALE
NPT LOW PRESSURE
CONNECTION
1/8 FEMALE NPT
HIGH PRESSURE
CONNECTION
5-15/64
[132.95]
3
[76.20]
4-9/32 [108.74]
11/16 [17.46]
2X R4-5/16
[109.54]
Ø7/8 [Ø22.23]
OPENING FOR 1/2
CONDUIT
CONNECTION
22.5°
1-1/2
[38.10]
7-3/4
[196.85]
8-1/4
[209.55]
8-7/8
[225.43]
2X 45°
1-17/64 [32.15]
3-1/64
[76.60]
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Phone: 219/879-8000
Fax: 219/872-9057
www.dwyer-inst.com
e-mail: [email protected]
®
