Strebel 40S-70, Installation Manual

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12
Assembly
Raising the return temperature
Thermal discharge safety device
Mounting the O
2
probe and the exhaust fume sensor
Raising the return temperature
The installation of a hydraulic
unit is mandatory
in boilers
from the Turbotec series, since
without a hydraulic unit the
regulatory behaviour of the boiler
does not proceed correctly in
combination with the lambda
control. In general, operating
temperatures which are too low
shorten the service life of a
boiler considerably. Especially in
the area of the water-cooled
ancillary heating surfaces, where
the exhaust fumes temperatures
are already relatively low, the
water vapour in the exhaust
fumes will condense if the
temperature falls below the dew
point. This condensate causes
corrosion, hence shortening the
service life of the boiler.
Corrosion due to the formation of
condensate is avoided in
Turbotec boilers by the following
measures:
- the feed temperature is
maintained at a high level by the
lambda control.
- The return temperature is
maintained above the dew point
by the mandatory hydraulic unit
(see hydraulic unit).
Thermal discharge safety
device
In heating systems according to
DIN 4751 sheet 2, solid fuels
may only be fired if the boilers
are equipped with a suitable
safety heat exchanger and a
type-test
ed ‘thermal discharge
safety device’. The two 1/2"
threaded nozzles (17) of the
safety heat exchanger are
located at the rear side of the
boiler and can be used optionally
as water inlet or water outlet.
The safety heat exchanger may
not be used under any
circumstances as an operational
water heater! The
‘thermomechanical valve’ must
be connected, non-isolatable, to
the water supply network,
observing the direction of flow.
The cold water preliminary
pressure must be at least 2 bar!
The response temperature of the
thermomechanical valve must
not exceed 100 °C. The safety
heat exchanger and the thermal
discharge safety device must be
serviced and checked annually
by an expert.
TV = thermomechanical valve
M = ½” sleeve for valve probe
D = drain
CW = cold water
It is essential to mount a funnel
and drain pipe for the ‘thermal
discharge safety device’ – no
water must be allowed to flow
onto mounted electrical devices!!
Mounting the O
2
probe and the
exhaust fume sensor
- Mount the exhaust fume sensor
on the exhaust fume nozzle and
connect the plug to the
connector strip at the
appropriate position (see plug
designation number).
- Screw the protective tube with
the pre-mounted O
2
probe into
the sleeve (21) on the exhaust
fume nozzle (the thread of the
protective tube is already
wrapped with Teflon tape) and
connect the plug to the
connector strip at the
appropriate position (see plug
designation number).
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