Faults - Bosch AGS10-2 Installation And Servicing Instructions

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Faults

Information regarding faults can also be found in the installation instructions for the controllers.
Type of fault
Effect Possible causes
Pump not running although start conditions are met.
The solar cylinder is not being Pump is faulty.
heated by solar energy.
Pump sticking due to physical blockage.
Pump is not responding to the controller.
Pump continually switching on and off.
Solar yield too low. Difference between controller cut-in and cut-out temperatures
too small.
Volumetric flow rate too high.
Temperature sensor position or contact is not correct.
Pump does not switch off.
Heat is being transferred out of Temperature sensor faulty or in wrong position.
the storage cylinder.
Controller faulty.
DHW too hot.
Risk of scalding Cylinder temperature limit and DHW mixer set too high.
DHW mixer faulty
DHW too cold (or inadequate volume).
DHW thermostat on the boiler, on the heating controller or on
the DHW mixer set too low.
Temperature differences in solar circuit are too high / flow temperature is too high / high collector temperature reached too quickly
Solar yield too low or system Faulty temperature sensor or controller malfunction.
damage.
Air in the system.
Volumetric flow rate too low.
Blocked pipework.
Collector arrays not hydraulically balanced.
Pressure drop in the system.
Solar yield too low. Loss of heat transfer fluid at joints.
Loss of heat transfer fluid through an open safety valve.
Vapour has escaped through open air vent (normal operating
function).
Frost damage.
No flow noticeable on flow rate indicator despite pump running.
Solar yield too low. The shut-off devices are closed.
Air in the system.
Indicator element in the flow regulator is sticking.
Noises in the collector array at high levels of solar exposure (vapour knocking).
Leakages in solar heating Even flow through the collector arrays is not possible.
circuit.
Expansion vessel too small or faulty.
Pump power is too low.
The collector with the collector temperature sensor is under
shade.
Flow and return swapped over.
Air in the system.
Table 17
AGS10-2, AGS10E-2, AGS20-2, AGS50-2
Remedy
Check the pump and replace if necessary.
Unscrew and remove the slotted screw on the pump head and use a
screwdriver to release the pump shaft. Do not strike the pump shaft
with the screwdriver.
See controller instruction manual.
Check controller settings.
Check and adjust the flow rate.
Check temperature sensor position.
Check temperature sensor position, installation and
characteristics.
Notice: speed-controlled pumps do not switch off immediately, but
only once the lowest speed is reached.
Set the cylinder temperature limit and DHW mixer to a lower setting.
Check the DHW mixer and replace if necessary.
Set the temperature as instructed in the applicable operating
instructions (maximum 60 °C).
Check that backup heating is functioning properly.
Check temperature sensor and settings of controller.
Bleed or purge the system.
Check/adjust the flow rate.
Check/flush the pipework.
Carry out hydraulic balancing.
Braze any leaks. Replace seals. Retighten screw fittings.
Check charge pressure and size of expansion vessel.
Close air vent after venting.
Check frost protection.
Open the shut-off devices.
Bleed or purge the system.
Clean the flow regulator.
Check piping.
Check design and charge pressure of the expansion vessel and
check operating pressure.
Check pump, replace if necessary.
Remove shade.
Check pipework, replace if necessary.
Bleed or purge the system and check slope of pipes.
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