Manual

0020115479_03 - 10/12 - Glow-worm
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MAINTENANCE
11.3 Fault diagnosis
The following checks should be performed before proceeding
onto specic diagnostics:
11.3.1
The faults described in this chapter should be carried
out by an engineer qualied to work on unvented
systems.
Malfunction Cause Solution
Cylinder
The cylinder cools down at night.
After the solar pump is switched o, the
supply and return lines have dierent
temperatures.
The collector temperature is
higher than the air temperature at night.
1. The anti-siphon valve is blocked. 1. Check the position of the blue handle.
2. Check the anti-siphon valve for tightness
(jammed cuttings, particles of dirt in the
sealing face).
3. Do not connect the solar heat exchanger
directly; instead, rst pull the supply lines
downwards and then upwards to the collector
(the siphon supports the antisiphon
valve) or mount a 2-way valve
which is switched at the same time as the
solar pump.
2. One-pipe circulation in the case of short
tube networks with low pressure loss.
Install an anti-siphon valve (as close as possible
to the cylinder).
Reheating is not working. The Gas-red
boiler runs for a short time,
goes o and then back on again. This is
repeated until the cylinder is at its target
temperature.
1. Air in the reheating heat exchanger Bleed the reheating heat exchanger.
1. The cold and hot water connections
on the cylinder have been mixed up.
Turn o the cold water supply, then let water
ow out via the hot water connection. Only a few
litres of water ow out if the connection is laid
correctly. The hot water withdrawal pipe intake
is then in the air space and further draining
is not possible. If it is possible to empty the
entire cylinder via the hot water connection, the
connections have been laid incorrectly.
Change the connections!
2. Hot water thermostat mixer set too low. Increase the setting.
3. Solar heating insucient; gas-red boiler does
not reheat.
External control device is faulty.
Air in the reheating heat exchanger.
Cylinder sensor is faulty.
Check whether the gas-red boiler is working.
Check whether the external control device is
working.
Check that the 2-way valve is in the DHW
position. Replace the 2-way valve.
Bleed the reheating heat exchanger.
Check the safety thermostat and suppress the
fault.
Replace the cylinder thermostat.
Water ows out of the expansion relief
valve (only when heating up).
Dirt on the valve seat of the expansion
relief valve.
Check the seat of the expansion relief valve and
suppress the fault.
Pressure limiting valve is faulty. If water only escapes during heating, switch
o the gas-red boiler and electric immersion
heater and check whether the pressure behind
the pressure limiting valve is lower than 3.0 bar.
If so, replace the pressure limiting valve.
Expansion vessel is faulty. Check the pressure in the expansion vessel.
If the pressure is insucient, reestablish the
pressure and check whether the expansion
vessel maintains it.
Expansion relief valve is faulty. If the pressure is normal, replace the expansion
relief valve.