Connecting The Collectors And Roof Outlet/Duct; Filling The Solar Thermal System; Pressure Test; Checking The System For Leaks - Stiebel Eltron SOL 27 BASIC Utilisation Et Installation

10.10 Connecting the collectors and roof outlet/duct

Using two flexible stainless steel corrugated tubes, connect the
collector array to the flushed pipework.
f Using flat packing and union nuts, attach the corrugated
pipes to the collector connections or the collector sensor
well.
The stainless steel corrugated tubes are factory-fitted with ther-
mal insulation that is resistant to temperature and UV.

10.11 Filling the solar thermal system

CAUTION Injury
!
f Put on protective gloves before handling the heat
transfer medium.
f Wear suitable safety goggles.
f Observe the EC's heat transfer medium safety da-
tasheet that is printed at the end of these instructi-
ons.
Before filling the heat transfer medium circuit, ensure that the
pipework installation has been completed, the collectors are con-
nected and the cylinder has been filled.
A powerful pump with an operating pressure of approximately
0.4 MPa (4 bar) should be used for filling. Due to the high flow
velocity, the air will be fully expelled.
Use only the heat transfer medium mentioned in the table "Speci-
fication". The bottles have been premixed and require no further
treatment.
Damage to the appliance and the environment
Never admix water or alternative heat transfer media.
Otherwise, the essential characteristics and corrosion
protection can no longer be guaranteed.
Damage to the appliance and the environment
Never fill the system during strong sunlight. This could
lead to steam hammer inside the collectors. Cover
the collectors.
10.11.1 Preparation
» Ensure that the collectors are covered for the pressure test.
» Remove the safety valve and close the connection.
10.11.2 Filling the solar thermal system
During all filling and draining procedures, open the air vent valve
at the highest point of the system. Close the shut-off valves ups-
tream of the air vents as soon as heat transfer medium is expelled.
f Using a hose, connect the pressure side of the fill pump to
the fill & drain valve beneath the pressure gauge.
f Connect the heat transfer medium container to the inlet side
of the pump.
f On the lower fill & drain valve, attach a drain hose and route
it into the heat transfer medium container.
f Close the adjusting valve in the solar module by turning the
slot on the flow rate adjusting screw (above the flow rate dis-
play) to the horizontal position.
f Disable the gravity brake by turning the fill & drain valve to a
45° position.
f Switch the fill pump ON.
Continue the filling process until no more bubbles are expelled
from the drain hose.
f Close the drain valve and fill up to a pressure of approxima-
tely 0.35 MPa (3.5 bar).
f Open the air vent valves at the highest point of the system
and close them again as soon as heat transfer medium is
expelled.

10.12 Pressure test

f Close the shut-off valves upstream of the air vent valves to
eliminate a loss of pressure.
f Using a hydraulic lifting pump, for example, pressurise the
system to 0.78 MPa (7.8 bar) in the system.
f Close the fill & drain valve on the filling side.
f Close the cap valve in order to be able to measure the
pressure drop.
The pressure must not drop for 15 minutes.
The system must be drained again to assemble the safety valve.
f Open the air vent valve at the highest point of the system.
f Open the adjusting valve in the solar module by turning the
slot on the flow rate adjusting screw (above the flow rate dis-
play) to the vertical position.
f To drain the system, open the fill & drain valves on the fill
and drain sides.
f Allow the system to fully drain.
f Open the cap valve.
Damage to the appliance and the environment
Following a pressure test, fit the safety valve.

10.13 Checking the system for leaks

Damage to the appliance and the environment
The thermal insulation may only be applied following a
successful leak test.
f Refill the system.
f Using the fill pump, build a pressure of 0.5 MPa (5 bar).
f The test pressure must not drop for a period of two hours.
f Pressure fluctuations are possible due to changing insolation
even when the collectors are covered.
f Carry out a visual inspection of all joints on the solar thermal
system.