Fault Diagnosis, Replacing the expansion vessel

∙Isolate the boiler using the appliance isolation valves on the flow and return connections to the boiler.

∙Remove the expansion vessel from the pipe work.

∙Refit a replacement expansion vessel in reverse order using a recognised method of sealing the threaded joint.

∙Open the isolation valves, ensure the system cold fill pressure is correct, there are no water leaks and the system is correctly vented of all air.

∙Isolate the boiler using the appliance isolation valves on the flow and return connections to the boiler.

∙Disconnect the pressure gauge tapping from the top of the relief valve.

∙Release the discharge pipe from the valve.

∙Remove the pressure relief valve from the pipe work.

∙Refit a replacement pressure relief valve in reverse order using a recognised method of sealing the threaded joint.

∙Open the isolation valves, ensure the system cold fill pressure is correct, there are no water leaks and the system is correctly vented of all air.

∙Isolate the boiler using the appliance isolation valves on the flow and return connections to the boiler.

∙Remove the pressure gauge from the pipe work as described above.

∙Depress the locating tabs on the gauge body and push the body through the mounting bracket.

∙Refit a replacement pressure gauge in reverse order ensuring the seal at the pressure relief valve is sound.

∙Open the isolation valves, ensure the system cold fill pressure is correct, there are no wa ter leaks and the system is correctly vented of all air.

8.Fault Diagnosis

If a fault develops, or is suspected, call your Service Engineer as soon as possible

Go through the following checklist before you make contact

∙Is the electricity supply on?

∙Are the lamps lit?

∙Has the limit thermostat tripped?

∙Are the boiler isolation valves open?

∙Are the pump isolation valves open?

∙Is the boiler switch on (giving a red “Power ON” light)?

∙Is the heating system water pressure correct?

∙Is the boiler temperature control set correctly?

∙Is the time clock (if fitted) calling for central heating?

∙Is the room thermostat (if fitted) set high enough?

∙Are the radiator valves open?

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