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Maintenance & servicing
Maintenance requirements
To ensure the continued optimum performance of the Andrews water heater it should be regularly maintained. This is of
particular importance in hard water areas or where the water supply contains particulate matter. Maintenance should be
carried out by a competent person and any replacement parts used should be authorised spare parts. It is recommended
that maintenance is carried out every 12 months and includes the checks detailed below.
In hard water areas consideration should be given to periodically descaling the immersion heater elements. To do this
the cylinder will need to be drained.
Check operation of safety valves
Slowly open the temperature and pressure relief valve by twisting its cap for a few seconds. Check water is discharged
and that it flows freely through the tundish and discharge pipework. Check valve reseats correctly when released.
NOTE: The water discharged may be very hot.
NOTE: Repeat the procedure for the pressure relief valve.
Clean the strainer
The strainer is incorporated within the pressure reducing valve housing of the valve. To inspect and clean the strainer:
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Turn off the isolating valve on the pressure reducing valve by turning the blue handle (if fitted in this position) so it
lies 90º to the direction of flow or the main stop cock to the house.
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Open the lowest hot tap in the system to relieve the system pressure.
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Using a spanner unscrew the pressure reducing cartridge and remove the moulded housing. The strainer will be
removed with the cartridge.
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Wash any particulate matter from the strainer under clean running water.
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Replace the strainer and screw the pressure reducing valve cartridge into the moulded housing.
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Close hot tap, turn on isolating valve by turning handle so it lies parallel to the direction of flow. Check for leaks.
Draining the Andrews water heaters
Switch off the electrical supply to the Auxiliary immersion heater(s) and shut down the boiler on indirect units. Turn off
the mains water supply to the Andrews water heater. Attach a hosepipe to the drain cock having sufficient length to
take water to a suitable discharge point below the level of the unit, at least one metre below the unit is recommended.
Open hot water tap nearest to the Andrews water heater to relieve the system pressure. Open drain cock. If water
fails to drain from the Andrews water heater vent the unit by manually opening the temperature / pressure relief valve.
Refilling system
DO NOT switch on the immersion heater(s) or boiler until the system has been completely refilled.
Close the drain tap. With the hot tap open, turn on mains water supply. When water flows from the hot tap allow to flow for a
short while to purge air and to flush through any disturbed particles. Close hot tap and then open successive hot taps in system
to purge any air. The electrical supply can now be switched on.
