Potterton Sirius Three WH-130, Installation, Operation And Maintenance Manual

31

7704679.01 (3-08/18)

24. ADJUSTMENT AND SAFETY DEVICES

The boiler has been designed in full compliance with European reference standards and in particular is equipped with the following:

• 

Limit thermostat

Thanks to a sensor placed on the CH flow line, this thermostat interrupts the flow of gas to the burner if the water in the primary 

circuit overheats.

• 

Exchanger flange thermostat (260°C)

This  device  is  located  on  the  exchanger  flange  and  interrupts  the  flow  of  gas  to  the  burner  if  the  front  insulation  yields  and 

overheats the exchanger or the flange gasket develops a fault. Press the reset button on the thermostat and eliminate the fault.

• 

Thermal fuse

This device is located at the rear of the exchanger and interrupts the flow of gas to the burner if the rear insulation yields and 

overheats the exchanger. If this device cuts in, dismount the exchanger and replace the thermal fuse (see paragraph “THERMAL 

FUSE REPLACEMENT OF HEAT EXCHANGER”).

  It is forbidden to disable this safety device.

• 

NTC flue sensor

This device is positioned on the fumes duct. The electronic board stops gas from flowing to the burner in case of over heating.

  The above reset operation is only possible if the temperature is less than 90°C.

 It is forbidden to disable this safety device

• 

Fumes pressure switch

This device stops the flow of gas to the burner when the pressure in the flue ducts exceeds 600 Pa. Under these conditions, the 

boiler is blocked and only after the fault has been eliminated can the boiler be ignited again (see section “FAULTS THAT CANNOT 

BE RESET BY THE USER”).

• 

Flame ionisation detector

The flame sensing electrode guarantees safety of operation in case of gas failure or incomplete ignition of the main burner. In 

these conditions, the boiler blocks.

• 

Hydraulic pressure switch

This device allows the main burner to be ignited only if system pressure is higher than 1 bar.

• 

Pump post-circulation

The electronically-controlled pump post-circulation function lasts 3 minutes and is enabled, in the heating mode, if the ambient 

thermostat causes the main burner to go out.

• 

Antifreeze device

The electronic boiler management system includes an "antifreeze" function for the heating and DHW systems which, when flow 

temperature falls below 5°C, operates the burner until a flow temperature of 30°C is reached. This function is enabled when the 

boiler is switched on, the gas supply is open and the system is correctly pressurised.

• 

Pump anti-block function

If no heat demand is received in the heating and/or DHW modes for 24 consecutive hours, the pumps will automatically start and 

operate for 10 seconds.

• 

Hydraulic safety valve (heating circuit)

This device is set to 6 bar and is used for the heating circuit. Connect the safety valve to a drain trap. Do not use it to drain the 

heating circuit.

• 

Heating pump pre-circulation

In case of a heat demand in the heating mode, the appliance can pre-circulate the pump before the burner is ignited. This pre-

circulation phase last from a few seconds to a few minutes, depending on the operating temperature and installation conditions.

•   

Gas pressure switch

This device enables the main burner only to be switched on if the gas pressure is over 12 mbar.

The functions performed by the adjustment and safety devices are only operative if the boiler is switched on.

25. ROUTINE MAINTENANCE INSTRUCTIONS

To keep the boiler efficient and safe, have it checked by a competent person at the end of every 12 months.

Careful servicing ensures economical and safe operation of the system.