ZTS 0201
Faults – correction
Any search for what caused a fault, or how to correct it, must only be carried out by a locally approved special-
ist (electrician). The unit must be disconnected from the power supply before opening the cover in any case.
A
If the water temperature fails to reach around 70°C from the start, despite setting the control knob to
its highest setting, please check whether the two thermostat sensors have been inserted in the correct
order and pushed all the way into the sensor housing tube (see step 9). Please also check that the
R 1½" screw-in muff is not more than 100 mm long.
B
If the fuse fitted upstream of the heater or the ELCB keeps tripping, but the unit is wired and connected
properly (no bare wires etc.), the heater is faulty, and must be replaced.
C
If water gets in through screw-in flange G 1½" or through the heater elements into the cover, the complete
unit must be replaced. If this fault occurs during the warranty period (12 months from fitting), check with
the installer. Check the whole hot water system for galvanic voltages (material mix, sacrificial anode, etc.).
If there is any galvanic corrosion, over which we have no control, our warranty is void.
D
If fuse(s) and ELCBs do not trip, but there is no hot water supply, check as follows:
1. Check the power supply to the heater is OK.
2. Set the control knob to its highest setting, and check against the circuit diagram whether the thermo-
stat 'connects' (peeps).
E
If the thermostat is not 'connecting', please remove it and press the temperature control reset button(s) on
the underside of the thermostat casing (2x – white). Check again that the thermostat is 'connecting'. If the
thermostat is still not 'connecting', it is faulty and needs to be replaced.
F
If the temperature control trips – 'reset buttons' must have been pressed – find the cause as follows:
1. Check the circuit diagram to see if the thermostat is wired properly. You can do this by heating the
longer and slightly thinner thermostat sensor to 30-50°C and checking whether it is working by turn-
ing the control shaft to 'hotter' and 'colder' (breaker contact). If it does not work, the thermostat is
faulty and needs to be replaced.
2. If the thermostat is working, check there is not too much scale on the heater elements. Descale them
if necessary.
Each time after correcting a fault, refit the screw-in heater as instructions and use.
12 VELUX
Thermostat
Sensor
Sensor wires
Insert the two sensors at least 330 mm
(until they hit the stop in the tube)
ZTS 0201
13 VELUX