Cleveland Controls
DIVISION OF UNICONTROL INC.
1111 Brookpark Rd
Cleveland OH 44109
Tel:
216-398-0330
Fax:
216-398-8558
Email:
Web page:
http://www.clevelandcontrols.com
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Cleveland Controls
Division of UniControl Inc.
LT-RSS-495-011.10
APPLICATION
The
Series RSS-495-011 Sensing Switch
Kit
provides an economical and convenient
solution for many residential and light com-
mercial HVAC applications. The kit contains
a compact
Series RSS-495
switch with an
adjustable set point range of 0.20" w.c. to
1.0" w.c. The switch has been factory set
to actuate on a pressure rise of 0.20" w.c.
The switch has a bleed hole (.016") in the
mounting pan. The individually boxed kit
includes a P/N 28419 hex wrench (
1
⁄
16
") for
field calibration, a P/N 28429 tube-to-tube
reduction adapter, and two (2) P/N 27577-
037 slotted hex head mounting screws (#6
x ⅜").
GENERAL DESCRIPTION &
OPERATION
The
RSS-495
switch has a thermoplastic
housing containing a diaphragm and snap-
acting switch. Duo-barbed sample line
connectors on each side of the diaphragm
accept ¼" ID or ⅜" ID slip-on flexible tubing.
The .016" bleed hole in the mounting pan
(low pressure side) prevents the build up of
condensation in the switch and sample line.
The electrical connection consists of three
(3) male 90º quick-connect terminals. The
snap action switch can be actuated by a
positive or negative pressure, or by a pres
-
sure differential.
MOUNTING (FIGURE 1)
Select a mounting location that is free from
vibration. Mount with the diaphragm in
any vertical plane in order to maintain the
specified operating set point. Do not mount
with the sample line connections directed
upward. Surface mount via the two 0.14"
slots in the integral foot bracket, using the
two (2) slotted hex head mounting screws
(#6 x ⅜") provided in the kit.
AIR SAMPLING CONNECTION
(FIGURE 2)
Refer to
Figure 2
to identify the
High inlet
(H)
and the
Low inlet (L)
. Connect the
sample lines as follows:
Positive Pressure Only:
Connect the
sample line to
H
;
L
remains open to the
atmosphere.
Negative Pressure Only:
Connect the
sample line to
L
;
H
remains open to the
atmosphere.
Two Negative Samples:
Connect higher
negative sample to
L
; lower sample to
H
.
Two Positive Samples
: Connect higher
positive sample to
H
; lower sample to
L
.
One Positive and One Negative
: Connect
positive sample to
H
; connect negative
sample to
L
.
ELECTRICAL CONNECTIONS
(FIGURE 3)
Before pressure is applied to the diaphragm,
the switch contacts will be in the normally
closed (
NC
) position as shown in Figure 3.
Connect the application wiring to the corre-
sponding switch terminals,
NC
,
NO
, and
C
.
FIELD ADJUSTMENT
(FIGURE 4)
The adjustable set point range of the
RSS-
495
is 0.20" w.c. to 1.0" w.c., ±0.05" w.c.
The switch leaves the factory calibrated
at 0.20" w.c. To adjust the set point, insert
the
1
⁄
16
" hex wrench (provided with the kit)
into the adjusting screw located between
the mounting feet on the underside of
the switch. Holding the switch so that the
diaphragm is vertical, rotate the adjusting
screw clockwise to the desired set point. The
maximum number of turns is 4-½, covering
Model
RSS-495-011
AIR PRESSURE SENSING SWITCH KIT WITH ADJUSTABLE SET POINT
the set point range of 0.20" w.c. to 1.0" w.c.
Do not exceed the maximum number of
turns.
Each full turn represents approxi-
mately 0.18" w.c. Determine the number of
turns required to approximately position the
adjusting screw as follows:
(REQUIRED SET POINT – INITIAL SET POINT @ 0.20)
0.18
= NUMBER OF TURNS CLOCKWISE
EXAMPLE:
REQUIRED SET POINT = 0.65" w.c.
INITIAL (FACTORY) SET POINT = 0.20" w.c.
(0.65 – 0.20) / 0.18 = 2.5 TURNS
Please note:
(1) Use a digital manometer and multi meter
(such as the
Cleveland Controls Series
6650 Digital Manometer
) to achieve pre-
cise set point calibration. Have the
RSS-495
switch as close to actual operating tem-
perature as possible during the calibration.
The
Cleveland Controls Series PVG-1
Pressure/Vacuum Generator
provides a
handy air source for calibration.
(2)
Warning: Never place an air
pressure sensing switch into operation
without confirming the set point first. An
incorrect setting could result in a hazard-
ous condition.
