Product Overview

Cleveland Controls
Division of UniControl Inc.
Model
DDP–106
Application
The Model DDP-106 is a general purpose proving switch
designed for HVAC and Energy Management applications. The
DDP-106 provides dual switching action: two separately-
operated, independently-adjustable SPDT snap-acting
switches are mounted on a common foot bracket. Differential
pressures up to 2 inches w.c. can be measured. Because the two
snap switches are set independently, an adjustable “deadband”
can be established for control circuits requiring both high and
low actuation points. Many control and alarm functions are
possible: for instance, monitor two pressure sources and sense
the differential for actuation at two independent set points.
General Description & Operation
Each of the two plated housings contains a diaphragm, a
calibration spring and a snap-acting SPDT switch. There are
two low pressure sample connections (one for each switch
assembly), and a common high pressure sample connection
(located on the foot bracket between the two low pressure
connections).
All three sample connections accept ¼" OD metallic
tubing via integral compression ferrule and nut fittings.
Mounting
Select a mounting location which is free from vibration. The
DDP-106 must be mounted with the diaphragm in any vertical
plane in order to obtain the lowest specified operating set point.
Avoid mounting with the sample line connections in the “up”
position. Surface mount via the two
3
/16" diameter holes in the
integral mounting bracket. The mounting holes are 7" apart.
Air Sampling Connection
The DDP-106 is designed to accept firm-wall sample lines of
¼" OD tubing by means of ferrule and nut compression
connections. For sample lines of up to 10 feet, ¼" OD tubing is
acceptable. For lines up to 20 feet, use ¼" ID tubing. For lines
up to 60 feet, use ½" ID tubing. Adapters, suitable for slip-on
flexible tubing are available: refer to Bulletin AFS08.01. Locate
the sampling probe a minimum of 1.5 duct diameters down-
stream from the air source. Install the sampling probe as close
to the center of the airstream as possible. Refer to the dimen-
sions drawing to identify the common high pressure inlet “H ”
(on the foot bracket) and the two low pressure inlets “L” (on
Element A and Element B). For each element, select one of the
following options and connect the sample lines as recom-
mended.
POSITIVE PRESSURE ONLY: Connect the sample line to inlet
H; inlet L remains open to the atmosphere.
NEGATIVE PRESSURE ONLY: Connect the sample line to
inlet L; inlet H remains open to the atmosphere.
TWO NEGATIVE SAMPLES: Connect the higher negative
sample to inlet L. Connect the lower negative sample to inlet H.
TWO POSITIVE SAMPLES: Connect the higher positive
sample to inlet H. Connect the lower positive sample to inlet L.
ONE POSITIVE AND ONE NEGATIVE SAMPLE: Connect
the positive sample to inlet H. Connect the negative sample to
inlet L.
Electrical Connections
For each element, before pressure is applied to the diaphragm, the
switch contacts will be in the normally closed (NC) position.The
snap switch has 90º quick-connect terminals. For each element,
wire alarm and control applications as shown in Figure 1.
Field Adjustment
The adjustment range of each of the 2 elements of the DDP 106
Air Switch is 0.05 ±.02" w.c. to 2.0" w.c.. To adjust an element’s
set point, turn the adjusting screw counterclockwise until motion
has stopped. Next, turn the adjusting screw 4 complete turns in a
clockwise direction to engage the spring. From this point, the next
ten turns will be used for the actual calibration. Each full turn
represents approximately 0.2" w.c.
Please note: To properly calibrate an air switch, a digital
manometer or other measuring device should be used to confirm
the actual set point.
Bulletin DDP106.00
Cleveland Controls
DIVISION OF UNICONTROL INC.
1111 Brookpark Rd
Cleveland OH 44109
Tel: [phone]
Fax: [phone]
Email:[e-mail]
Web page: http://www.clevelandcontrols.com
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