Maintenance; Protech Anti-Corrosion System; Thermal Cut-Out(S); Immersion Heater(S) - Ariston ST 50 ProTech Instructions For Installation, Servicing & Operation

5. MAINTENANCE
To ensure efficient and safe operation, and to maintain the warranty, it is
necessary to ensure the appliance is serviced annually by a competent
person.
Before servicing, preliminary electrical system checks must be carried out to
ensure electrical safety (i.e. polarity, earth continuity, resistance to earth and
short circuit).
5.1 ProTech
Anti-corrosion System
WARNING: SWITCH OFF THE POWER SUPPLY BEFORE WORKING ON
THE APPLIANCE.
Trouble-shooting:
1) The green L.E.D. is NOT on:
- Check to see that the circuits electric plug is connected (if not,
connect);
- Check to see that the P.C.B, is supplied with electricity (if not, replace
the supply cable);
- Check to see that 230 V electricity is supplied (if not, ensure that 230 V
is supplied);
- If all these checks fail to locate the problem, replace the electronic
circuit (installer).
2) The red L.E.D. is on:
- Check to see that the tank is filled with water (if not, fill it before
carrying out the following checks);
- Check to see that the clip-on circuit connector is in the proper position
(if not, position correctly);
- Check to see that the electrodes connection lead is property connected
(to check this, gently pull on it) (if not, replace the electrode);
- Check to see that the connection lead to the tank is properly connected
to the tank (if not, connect properly);.
- Check to see thait the two leads from the clip-on circuit connector are
not damaged, stripped, etc. (if so, replace the electrode);
- If all these checks fail to locate the problem, replace the electronic
circuit.
Note: To replace the RC.B, there is no need to drain the cylinder;
1) Disconnect the two supply cables from the P.C.B. to the supply terminal;
2) Disconnect the clip-on circuit connector and polarising slot which
connects the circuit to the tank and the electrode;
3) Disconnect the P.C.B. from its supporting plate (plastic clips in the 4
corners) and;
4) Replace the defective circuit with a new one, then re-install in reverse
order to the above.
5.2 Thermal Cut-out(s)
If the thermal cut-out has operated the cause must be found before resetting
(see section 6).
5.3 Immersion Heater(s) Should the immersion heater(s) become scaled, we would recommend that
the immersion heaters be replaced, a scale reducer be fitted on the cold
water supply to the cylinder and that the thermostat is set below 60°C to
prevent further scale formation.
5.4 Unvented Controls
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Check controls as per the following:
1) Line strainer - with the water supply turned off remove screen from
strainer and clean off any debris;
2) Expansion vessel - with the water supply turned off and taps open, check
expansion vessel pressure and top up as necessary;
3) Temperature & pressure relief valve - with the water supply turned on,
check manually by lifting the test lever/turning the test knob (ensure valve