STIEBEL ELTRON sol 20 si Bedienung Und Installation Seite 20

fault
The pump is running, but no flow rate
is discernible at the flow meter with
balancing valve.
Pump appears to open late and stop early. Excessive temperature differential between
The pump starts and switches itself off
again shortly afterwards. This is repeated
a few times until the system runs correctly.
The same happens in the evening.
The pressure gauge indicates a drop in
pressure.
The pump runs noisily.
System is noisy. This is normal in the first
few days after filling the system. Two
possible causes, if this occurs later:
The cylinder cools down over night. After
the pump has stopped, the flow and return
operate at different temperatures; the
collector temperature is higher at night
than the outside temperature.
Reheating does not work. The boiler runs
for a short while, stops and restarts again.
This repeats frequently, until the cylinder
has reached its set temperature.
The cylinder cools down excessively.
The pump does not stop.
20
cause
Flow meter with balancing valve stuck or
faulty.
Shut-off valve closed.
the collector and the cylinder.
The insolation is still insufficient for heating
up the entire pipework.
Excessive flow rate (pump set too high).
The switching temperature differential of the
control unit is set too low.
Pipework not fully insulated.
The cylinder and collector sensors are
interchanged (problem occurs after
commissioning).
A pressure drop shortly after the system is
filled is quite normal, as air is still escaping
from the system. A pressure drop later on
can be caused by an air lock that has shifted
later on. In addition during normal operation
the pressure fluctuates by 0.2–0.3 bar
depending on the system temperature. If the
pressure drops continuously, the system is
leaking somewhere.
Fluid loss as a result of opening the safety
valve, because the expansion vessel is not
large enough,or it is depressurised or faulty.
Collector damage (leaking) and frost damage
through insufficient frost protection.
Air in the pump.
Inadequate system pressure.
System pressure too low. The pump draws
in air via the air vent valve.
The pump rate is set too high.
The gravity brake does not close.
Single pipe circulation for short pipework
with low pressure drop.
Air in the reheat heat exchanger.
Heat exchanger area too small.
Insulation faulty or incorrectly fitted.
Reheating control unit setting.
DHW circulation runs too frequently and/or
at night.
Sensor or sensor position not OK.
Control unit not OK.
remedy
Check the function of the flow meter with balancing valve. A
ceased ring can block the display in the sight glass, even if the
meter is correctly connected or the flow is incorrectly adjusted.
Start the pump in manual mode; the pump piston movement
should be discernible. Release the piston through tapping it
lightly; in emergencies, replace the flow meter with balancing
valve.
Open the shut-off valve.
Reduce the temperature differential at the control unit.
Check for faults again when there is strong insolation.
Reduce the pump rate.
Increase the switching temperature differential at the
control unit.
Insulate the pipework.
Connect the temperature sensors to the correct sensor
terminals (see the control unit installation and operating
instructions).
Automatic air vent valve closed?
Check threaded fittings, glands on shut-off valves and
threaded connections, and then check the soldered joints.
Check the pre-charge pressure of the expansion vessel and
ensure the diaphragm is not leaking.
Check the size of the vessel.
Check the anti-freeze content and the pH value.
Vent the pump.
Increase the system pressure.
Increase the system pressure.
Change to a lower pump rate and check the flow rate at the
flow meter with balancing valve.
Check the position of the setting handle and check the gravity
brake for leaks (jammed swarf, dirt particle on the sealing
surface).
Change the line routing. Never connect the solar heat
exchanger directly but draw the supply lines first in a U
downwards (a siphon assists the gravity brake). If required,
install a two-way valve that is switched simultaneously with
the pump.
Install a gravity brake in the flow or a heat insulating loop.
Vent the reheat heat exchanger.
Compare the details supplied by the boiler manufacturer
and those of the cylinder manufacturer. The problem may be
resolved by selecting a higher flow temperature at the boiler.
Check the insulation; insulate the cylinder connections.
Check the boiler control unit setting.
Check the switching times and interval operation.
Check the sensor position, installation and curves.
Note: The variable speed pump does not stop immediately,
but only after it reaches its lowest speed.