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TECHNICAL ASSISTANCE SERVICE
FAULT
The safety valve keeps opening.
Reduced supply of domestic hot
water.
Solar heating system inefficient.
The solar circuit pump does not
work, even if the collector tempe-
rature sensor detects a temperatu-
re higher than that in the storage
cylinder.
The storage cylinder loses a lot of
heat overnight.
CAUSE
Problem with CH circuit safety valve. − Check valve setting and efficiency.
Circuit pressure too high.
Problem with CH circuit expansion
vessel.
Supply pressure is too high.
Lime scale and/or sludge in storage
cylinder.
Flow rate too high.
Solar controller needs reprogram-
ming .
Air in circuit.
Flow rate too low or too high.
Pressure is low.
Maximum temperature has been
exceeded in the collector or in the
storage cylinder.
No electrical power.
Temperature differential too great
for pump to operate, or controller
not working.
There is natural circulation to the
collectors.
54
SOLUTION
− Check circuit pressure.
− Check pressure reducer.
− Check efficiency of expansion vessel.
− Fit a pressure reducer.
− Check and clean.
− Fit a flow reducer.
− Check functioning of DHW circuit
pump.
− Check positioning of sensors.
− Check boiler operating temperature.
− Check temperature setting of thermo-
static mixer valve.
− Reduce the speed of the solar circuit
pump first. Then turn the flow rate
adjustment screw on the valve group
to set a flow rate of 30l/h per m 2 of
collector area.
− Make sure that the ∆T between the
collector and the storage cylinder is
not too high or too low. Set a ∆T of
8-10°C.
− Bleed the circuit.
− Check that the flow rate is about
30l/h per m 2 .
− Check that the cold pressure of the
system is approximately 3 bar.
− Solar controller has reached maxi-
mum temperature and stopped the
pump. The pump will start working
again as soon as the temperature
drops in the collectors.
− Check the safety devices and electri-
cal connections.
− Check the controller and the tempe-
rature sensor, or reduce the tempera-
ture differential setting.
− Make sure that the non-return valve
is sealed and closes properly. Replace
if necessary.
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