Buderus 7735501684, Installation And Maintenance Instructions Manual

Page: 39 / 80

6 Commissioning
SF500.5... | SF750.5... | SF1000.5... – 6 720 821 497 (2017/05) 39
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).
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.
6 Commissioning
▶ Commission all assemblies and accessories as specified in the
manufacturer's technical documents.
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
▶ 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.
Gas supply
pressure
(static pressure) Excess pressure for
pressure relief
valve
Pressure reducer
Within
the EU
Outside the EU
< 4.8 bar

6 bar Not
required
Not
required
5 bar 6 bar

4.8 bar

4.8 bar
5 bar

8 bar Not
required
Not
required
6 bar

8 bar

5.0 bar Not required
7.8 bar 10 bar

5.0 bar Not required
Table 7 Selection of a suitable pressure reducer
▶ Ensure that the sensor area has contact with the
sensor pocket area for the sensor‘s full length.
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.
Only carry out the leak test for the DHW cylinder with
potable water.
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.