IM-P403-89
EMM Issue 8
20
Optional
OK
BC3250
100
50
0
%
SP
PV
AL
Fig. 13 CCD system
Dump valve
(spring-
to-open).
Opens when
conductivity
level is above
set point
allowing
contaminated
condensate to
flow to drain.
I s o l a t i n g v a l v e
(spring-to-close)
opens to allow clean
condensate to be
returned to the boiler.
Fig. 14 Alternative
arrangement of a CCD
system using separate
valves
Spring retract pneumatic
actuator
QL 3-port diverter valve
Check valve
Bypass
line
Conductivity
sensor and
temperature
sensor
500
mm
head
3.6 Typical applications -
Condensation
contamination detection
system (CCD)
System description
WARNING:
Most countries have
regulations that limit temperature and
contamination levels for fluids being
dumped to drain. It is essential to follow
the guidelines issued by bodies such as
the UK Health and Safety Executive.
The Spirax Sarco CCD system monitors
and displays the conductivity of
condensate return, and will redirect the
flow to drain if the conductivity increases
above a pre - set level to avoid
contaminated water being returned to the
boiler feedtank. It will not detect
contaminants that do not change the
conductivity, e.g. oils, fats, or sugars.
A conductivity sensor and a temperature
sensor are mounted in a bypass line as
shown in Figure 13. A check valve in the
main line ensures a flow past the sensor
under low flow conditions. The 500 mm
head prevents flash steam flow in the
bypass line. We recommend a 3-port
diverter valve such as the Spirax Sarco
QL. A spring retract pneumatic actuator
is normally fitted to cause the valve to
divert on failure of the air supply.
Alternatively, two 2-port valves (M20, for
example) may be used as shown in Figure
14, one as a spring-to-close isolating
valve in the condensate return line, and
one as a spring-to-open dump valve, in
the drain line. On detection of high
conductivity, the isolating valve closes
and the dump valve opens, both under
spring pressure. Suitable 3-port solenoid
valves may be selected from the Spirax
Sarco range, and are described in
separate literature.
Summary of Contents for BC3250
Page 76: ...IM P403 89 EMM Issue 8 76...
