Potterton NXR3 Installation, Operation And Maintenance Manual page 21

POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3
CB 120
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2
3
4
The CB 120 module provides the following functions:
1. Reset button – if during normal operation the flame is lost then the boiler will proceed to go to a lockout
condition to reset the lockout press this button. For repeated lockouts please contact your service agent.
2. Overheat thermostat – if overheat indicator light is illuminated then the overheat thermostat needs to be re-
set, this is achieved by removing the hexagonal cap and pressing the reset. The overheat thermostat will
operate at 110° C, investigation into the reason of lockout should be carried out.
3. Overheat indicator – the indicator light will illuminate to inform you the boiler has gone to an overheat
condition and will not re-start until a manual reset has taken place as described above.
4. Lockout indicator – if during the burner lighting sequence the control box fails to detect the pilot flame or it
goes out during operation then the burner will go to lockout and the light will be illuminated.
5. Mains supply indicator – indicates that the power has been turned on to the boiler.
6. On/Off switch – turns the burner On or Off. This is not a boiler isolator switch, components are still live
even when the switch if off (mains inlet to the boiler still requires a suitable 3-pole isolator).
7. Over-ride button for safety checks – if this button is depressed it bypasses the control and high/low
thermostats and fires the boiler on high fire, it is used to check the operation of the overheat thermostat.
8. Over-ride thermostat – (set to the right (maximum position) allowing control by the 1
thermostats.
9. 6.3 Amp Fuse
10. Boiler thermometer – indicates the current boiler temperature.
Also supplied are a 1
supplied for indication of the flue gas temperature, to fit the flue gas thermometer drill a 7.5mm diameter hole,
preferably vertically, in the flue between the flue hood and the stack, insert the thermometer and clip.
5 6
7
st nd
Stage & 2 Stage hours run meters for indication purposes. A flue gas thermometer is also
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SECTION 4
PAGE 19
st nd
stage and 2 stage