Buderus SM400/5E, Installation And Maintenance Instructions Manual

Page: 23 / 116

6 Commissioning
SU300/5 | SU400/5 – 6 720 800 019 (2015/04) 23
5.2 Hydraulic connection
5.2.1 Connecting the DHW cylinder on the water side
System example with all recommended valves and stopcocks
(

Fig. 11, page 108).
▶ Use installation material that is heat-resistant to 160 °C (320 °F).
▶ Never use open vented expansion vessels.
▶ Use metal connection fittings in DHW heating systems with plastic
lines.
▶ Size the drain line in accordance with the connection.
▶ To facilitate blow-down, never install bends in the drain line.
▶ Keep primary lines as short as possible and insulate them.
▶ If using a non-return valve in the cold water supply: Install a safety
valve between the non-return valve and the cold water inlet.
▶ Install a pressure reducer if the static system pressure is in excess of
5 bar.
▶ Seal all superfluous connections.
5.2.2 Installing a safety valve (on-site)
▶ Install a type-tested safety valve that is approved for potable water
(
≥
DN 20) in the cold water supply (

Fig. 11, page 108).
▶ Observe the safety valve installation instructions.
▶ Terminate the discharge pipe where it will be easily visible in the
frost-protected area above a drain.
– The discharge pipe must be at least equal to the outlet cross-
section of the safety valve.
– The discharge pipe must be able to discharge at least the flow rate
that is feasible at the cold water inlet (

Table 4, page 21).
▶ Attach a notice with the following text to the safety valve: "Never
close the discharge pipe. During heating, water may be discharged
for operational reasons."
If the static system pressure exceeds 80 % of the safety valve response
pressure:
▶ Install a pressure reducer upstream (

Fig. 11, page 108).
5.3 Installing the DHW temperature sensor
Fit one DHW temperature sensor respectively at test port [7] (for the
solar thermal system) and [3] (for the heat source) for capturing and
monitoring the DHW temperature at the DHW cylinder
(

Fig. 3, page 105).
▶ Install the DHW temperature sensor (

Fig. 12, page 108). Ensure
that the sensor area has contact with the sensor well surface area
over its full length.
5.4 Immersion heater (accessory)
▶ Install the immersion heater in accordance with the separate
installation instructions.
▶ When installation of the cylinder is complete, inspect the earth
conductor (including metal connection fittings).
6 Commissioning
▶ Commission all assemblies and accessories as specified in the
manufacturer's technical documentation.
6.1 Commissioning the DHW cylinder
On the DHW side, the test pressure must not exceed 10 bar (150 psi)
positive pressure.
▶ Flush the DHW cylinder and pipework thoroughly prior to
commissioning (

Fig. 14, page 109).
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 safety valve.
▶ Hand all enclosed documents over to the user.
▶
User recommendation: Arrange an inspection/maintenance
contract with an approved heating contractor. Have the DHW
cylinder inspected and, if required, serviced annually in accordance
with the service intervals stated (

Table 7, page 24).
▶ Highlight the following for the user:
– Water may be discharged from the safety valve during heat-up.
– The safety valve discharge pipe must always be kept open.
– Service intervals must be observed (

Table 7, page 24).
– Recommendation in the case where there is a risk of frost and
when the user is briefly away:
Keep the DHW in operation and
select the lowest possible DHW temperature.
WARNING: Risk of fire through soldering and welding!
▶ Take appropriate safety measures when soldering
and welding as the thermal insulation is flammable.
For example, cover up the thermal insulation.
▶ Check cylinder casing after completion for perfect
condition.
WARNING: Risk to health through contaminated water!
Work carried out without due care for cleanliness
contaminates the potable water.
▶ Install and equip the DHW cylinder hygienically in
accordance with national standards and guidelines.
Mains pressure
(static
pressure) Safety valve
response
pressure Pressure reducer
in the EU outside the EU
< 4.8 bar
≥
6 bar Not required
5 bar 6 bar max. 4.8 bar
5 bar
≥
8 bar Not required
6 bar
≥
8 bar max. 5.0 bar Not required
7.8 bar 10 bar max. 5.0 bar Not required
Table 6 Selection of a suitable pressure reducer
NOTICE: Risk of system damage through excessive
pressure!
Excessive pressure can result in tension cracks in the
enamel coating.
▶ Never close the blow-off line of the safety valve.
Check the DHW cylinder for leaks using potable water
only.
WARNING: Risk of scalding at the hot water draw-off
points!
There is a risk of scalding at the hot water draw-off
points if the DHW temperature is set above 60 °C and
during thermal disinfection.
▶ Advise users that they should only draw off mixed
water.