ProMinent DULCOMETER PH-501 Assembly And Operating Instructions Manual page 116

INSTALLATION
1. Select a location free form excessive vibration and where oil or
water will not drip upon the switch. See special housings for
unusual conditions.
2. While not required, positioning the pressure connections
down is recommended. Mount the switch with the diaphragm
in a vertical plane. Switch with the diaphragm in a vertical plane.
Switch must be recalibrated for each change in operating
position.
3. Connect switch to source of pressure differential. Metal tubing
with 1/4" O.D. is recommended but any tubing system which
will not restrict the air flow is satisfactory. Note that the low
pressure connection may be made to the 1/2" spud at the back
of the switch if desired. If so connected, drill 1/16" diameter
holes in the Spring Retainer flange and the head of Adjustment
Screw to provide opening to the switch interior and plug the
other low pressure connection.
4. Electrical connections to the standard single pole, double throw
snap switch are provided by means of screw terminals marked
"common", "norm open", and "norm closed". The normally
open contacts close and the normally closed contact open
when pressure increases beyond the set point.
5. Switch loads should not exceed the maximum specified current
rating of 15 amps resistive. Switch capabilities decrease with
high load inductance or rapid cycle rates. whenever and
application involves one or more of these factors, the user may
find it desirable to limit the switched current to 10 amps or less
in the interest of prolonged switch life.
ADJUSTMENT
1. If the switch has been factory preset, check the set-point before
placing in service to assure it has not shifted in transit.
2. If switching has not been preset or it is desired to change the
point, observe the following procedure:
a. To adjust the set point turn the slotted Adjustment Screw
clockwise to increase the set point and counterclockwise to
decrease the set point.
b. The following is a recommended procedure for calibrating or
checking calibration: Use a "T" assembly with three rubber
tubing leads, all as short as possible and the entire assembly
offering minimum flow restriction. Run one lead to the
pressure switch, another to a manometer of known accuracy
and appropriate range, and apply pressure through the third
tube. Make final approach to the set point slowly. Note the
manometer and pressure switch will have different response
characteristics due to different internal volumes, lengths of
tubing, oil drainage, etc. Be certain switch is checked in
position it will assume in use, i.e. vertical, horizontal, etc.
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A.
6 [15.40]
4 [101.60]
SQ
TYP
3
1/2 FEMALE NPT
[76.20]
CONDUIT
6-3/4
CONNECTION
[171.45] TYP
7-1/2
[190.50]
Weatherproof Enclosure
16 ga. steel enclosure for unusually wet or oily conditions.
Withstands 200 hour salt spray test. Gasketed cover. Weight 5-1/2
lb (2.5 kg). Switch must be installed at factory. Specify "WP" in
addition to switch catalog number.
1/8 FEMALE NPT
HIGH PRESSURE
CONNECTION
5-7/8
4-1/4
6-3/8
[149.23]
[107.95]
[161.93]
TYP
TYP
4-1/4
[107.95] TYP
1/8 FEMALE NPT
LOW PRESSURE
CONNECTION
Explosion-Proof Housing
Cast iron base and aluminum dome cover. Approximate weight 7-
1/2 lb (3.4 kg). Specify "EXPL" in addition to switch catalog
number.
Phone: 219/879-8000
Fax: 219/872-9057 e-mail: info@dwyer-inst.com
1-1/2 [38.10]
1/8 FEMALE NPT
1-1/4 [31.75]
LOW PRESSURE
3/32 [2.38]
CONNECTION
Ø5/16 [7.94]
1-1/2 [38.10] TYP
MOUNTING
1/8 FEMALE NPT HIGH
HOLES
PRESSURE CONNECTION
TYP 4 PLACES
1-7/16
[36.53]
4-1/6
3/4 [19.05]
[103.19]
CLEARANCE FOR
COVER REMOVAL
Ø5/16 [7.94]
TYP 4 PLACES
1/2 FEMALE NPT
7/16
[11.11]
2-3/4
3-3/4
[70.61]
[95.25]
6-15/16
CLEARANCE
[176.21]
FOR COVER
REMOVAL
www.dwyer-inst.com
E-1251
COUNDUIT
CONNECTION
1-1/16
[26.99]