Unvented Cylinder Manual 09_12

5. MAINTENANCE To ensure

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 that 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 P.C.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 O C to prevent further scale formation. 5.4 unventeD controls 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 26

closes after testing); 4) Expansion relief valve - check manually by turning the test knob (ensure valve closes after testing); 5) Discharge pipes (D1) - from both temperature & pressure relief and expansion relief valve for obstructions; 6) Tundish & discharge pipe (D2) - open either valve gradually to produce a full bore discharge into tundish and D2 without any back pressure; 7) Pressure reducing valve - check that the correct outlet pressure is being maintained by recording the pressure at an in-line terminal fitting e.g. tap. 5.5 tHerMostAts 5.6 MAintenAnce proceDure Ensure that all thermostats are adjusted for the correct temperature setting, this should be between 60 and 65°C. To ensure efficient and safe operation, and to maintain the warranty, it is necesary to ensure the appliance is serviced annually by a competent person. After servicing, preliminary electrical system checks must be carried out to ensure electrical safety (i.e. polarity, earth continuity, resistance to earth and short circuit). IMPORTANT NOTE: TO AVOID POTENTIAL IMPLOSION OF THE CYLINDER WHILST DRAINING, ALL TAPS AND THE T&P VALVE MUST BE OPEN TO ALLOW AIR INTO THE CYLINDER DURING THE DRAINING PROCESS. To drain the cylinder it is necessary to proceed as follows: 1) Close the mains supply service valve; 2) Open hot water taps; 3) Manually open the T&P Valve; 4) Attach a hose and open the drain cock and allow the cylinder to empty, taking care of hot water contained in the cylinder. (Pumping the water out will completely drain the cylinder) Magnesium Anodes (stD and sti models only) No longer than every 12 months, the installer should check the magnesium anti-corrosion anodes (consult the label on the face of the unit for the correct location). Assessment of the condition of the bottom anode (where fitted) can be made by judging the condition of the top anode. Removal of anodes; 1) Close the mains supply service valve; 2) Open all hot water taps; 3) Attach a hose and open the drain cock and allow the cylinder to empty; 4) The anodes are removed by unscrewing; EXAMINE THE ANODES AND IF THE DIAMETER IS LESS THAN 10mm replace both anodes. The use of an approved P.T.F.E. sealing tape is required to ensure watertight connection for anodes. thermal cut-out(s) If the thermal cut-out has operated the cause must be found before resetting. immersion Heater(s) Should the immersion heater be scaled, we would recommend it be replaced. unvented controls(s) Check controls as per the following: 27