Installing A Pressure Relief Valve (Provided By The Customer); Fitting The Hot Water Temperature Sensor; Commissioning; Commissioning The Dhw Cylinder - Buderus SF500.5 serie Installations- Und Wartungsanleitung Für Den Fachmann

5.3.2 Installing a pressure relief valve (provided by the
customer)
▶ Install a pressure relief valve that is approved for potable water
(DN 20) in the cold water pipe ( Fig. 19, page 72).
▶ Observe the installation instructions for the pressure relief valve.
▶ Terminate the discharge pipe of the pressure relief valve via a
dewatering point, which is located in a frost-proof area that is easily
visible.
– The discharge pipe must be at least equal to the outlet cross-
section of the pressure relief valve.
– The discharge pipe must be able to discharge at least the flow
rate, which may possibly arise at the cold water inlet
( tab. 3, page 36).
▶ Attach a notice with the following text to the pressure relief valve:
"Never close the discharge pipe. During heating, water may be
discharged for operational reasons."
If the static pressure in the system exceeds 80 % of the response
pressure for the pressure relief valve:
▶ Install a pressure reducer upstream ( Fig. 19, page 72).
Gas supply Excess pressure for
pressure pressure relief
(static pressure) valve
6 bar
< 4.8 bar
5 bar 6 bar
8 bar
5 bar
8 bar
6 bar
7.8 bar 10 bar
Table 7 Selection of a suitable pressure reducer
5.4

Fitting the hot water temperature sensor

For measuring and monitoring the DHW temperature at the cylinder:
▶ Fitting the DHW temperature sensor ( Fig. 20, page 72).
Positions of the test points:
• SF500...1000.5... ( Fig. 2, page 67):
Fit activation and deactivation sensors at position 4 and 5.
▶ Ensure that the sensor area has contact with the
sensor pocket area for the sensor's full length.
SF500.5... | SF750.5... | SF1000.5... – 6 720 821 497 (2017/05)
Pressure reducer
Within
the EU Outside the EU
Not Not
required required
4.8 bar 4.8 bar
Not Not
required required
5.0 bar
Not required
5.0 bar
Not required
6

Commissioning

NOTICE: Risk of system damage from excessive
pressure.
Excessive pressure can result in tension cracks in the
enamel coating.
▶ Never close the blow-off line of the safety relief valve.
▶ Commission all assemblies and accessories as specified in the
manufacturer's technical documents.
Only carry out the leak test for the DHW cylinder with
potable water.
6.1

Commissioning the DHW cylinder

After the cylinder has been filled, it must be subjected to a pressure test.
On the DHW side, the test pressure must not exceed 10 bar (150 psi)
positive pressure.
▶ Carrying out the leak test ( Fig. 23, page 73).
▶ Flush the DHW cylinder and pipework thoroughly prior to
commissioning ( Fig. 24, page 73).
6.2

Instructing users

WARNING: Risk of scalding at the DHW draw-off points!
There is a risk of scalding at the DHW draw-off points
during thermal disinfection and if the DHW temperature
is set above 60 °C.
▶ Advise users that they should only draw off mixed
water.
▶ Explain the operation and handling of the heating system, the
primary store system and the DHW cylinder, making a particular
point of safety-relevant features.
▶ Explain the function and checking of the pressure relief valve.
▶ Hand all enclosed documents over to the owner/operator.
▶ Recommendation for the user: Sign a maintenance and inspection
contract with an approved contractor. Have the DHW cylinder
serviced and inspected annually at the specified service intervals
( tab. 8, page 40).
▶ Highlight the following points to the user: setting the DHW
temperature.
– When heating-up, water may be discharged from the pressure
relief valve.
– The discharge pipe for the pressure relief valve must always be
kept open.
– Service intervals must be observed ( tab. 8, page 40).
– Where there is a risk of frost and when the user is briefly
away: Keep the heating system in operation and set the lowest
possible DHW temperature.
Commissioning 6
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