Buderus SM 5E Series, Manual, Page: 29 / 168

6 Commissioning
SU500-1000.5... | SM500-1000.5E | SMH400-500.5E... – 6 720 810 363 (2015/11) 29
5.3.2 Installing a pressure relief valve (provided by the
customer)
▶ Install a pressure relief valve that is approved for potable water
(

DN20) in the cold water pipe (

Fig. 22, page 160 and Fig. 21,
page 159).
▶ 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. 4, page 25).
▶ 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. 22, page 160 and
Fig. 21, page 159).
5.4 Fitting the DHW temperature sensor
For measuring and monitoring the DHW temperature at the cylinder:
▶ Fitting the DHW temperature sensor (

Fig. 23, page 160).
Positions of the sensor test points:
• SM500-1000.5E and SMH400-500.5E... (

Fig. 8, page 155):
Fit sensor for heat source at Position 3. Fit sensor for solar system at
Position 7.
• SU500-1000.5E (

Fig. 7, page 155):
Fit sensor for heat source at Position 3.
5.5 Immersion heater (accessory)
▶ Install the immersion heater in accordance with the separate
installation instructions.
Cut out the perforation in the foil jacket or in the separate thermal
insulation.
▶ When the cylinder installation is complete, inspect the ground
conductor. Include metal connection fittings in this procedure.
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. 26, page 161).
▶ Flush the DHW cylinder and pipework thoroughly prior to
commissioning (

Fig. 27, page 161).
6.2 Instructing users
▶ Explain the operation and handling of the heating system and 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 user.
▶
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. 9, page 30).
Highlight the following for 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. 9, page 30).
– 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.
Mains
pressure
(static
pressure)
Response 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 8 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: Danger of cylinder damage through positive
pressure!
Positive pressure can cause tension cracks in the enamel
coating.
▶ Never close the discharge pipe for the pressure 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 at

60 °C.
▶ Advise users that they should only draw off mixed
water.