Maintenance; General; Standard Inspection & Maintenance Operations - Heatrae Sadia PremierPlus Installation And User Manual

9. Maintenance

9.1 General

Maintenance requirements
Unvented hot water systems have a continuing
maintenance requirement in order to ensure safe
working and optimum performance. It is essential
that the relief valve(s) are periodically inspected and
manually opened to ensure no blockage has occurred
in the valves or discharge pipework. Maintenance of
this appliance should only be carried out by a suitably
qualified person. Failure to do so could invalidate the
warranty.
Similarly cleaning of the strainer element and
replacement of the air in the expansion vessel will help
to prevent possible operational faults.
The maintenance checks described below should be
performed by a competent person on a regular basis,
e.g. annually to coincide with boiler maintenance.
After any maintenance, please complete the relevant
Service Interval Record section of the Benchmark
Checklist on page 26 of this document.
9.2 Standard inspection & maintenance
operations
Inspection
The immersion heater boss can be used as an access
for inspecting the cylinder internally.
Safety valve operation
CAUTION
Water discharged may be very hot!
` Manually operate the temperature/pressure relief
valve 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.
` Repeat the above procedure for the expansion
relief valve.
Strainer
` Turn off the isolating valve prior to the Pressure
Reducing Valve or the main stop cock to the system.
` Open the lowest hot tap in the system to relieve
the system pressure.
` Using a spanner unscrew the pressure reducing
cartridge and remove the moulded housing. The
strainer will be removed with the cartridge.
` Wash any particulate matter from the strainer
under clean running water.
` Replace the strainer and screw the Pressure
Reducing Valve cartridge into the moulded
housing.
` Close hot tap, turn on isolating valve or main stop
cock to the system. Check for leaks.
` Descaling immersion heater(s)
` Turn off the mains water supply, isolate the electrical
supply and turn off boiler
Attach a hosepipe to the drain cock having sufficient
`
length to take water to a suitable discharge point
below the level of the unit.
` Open a hot tap close to the unit and open drain
cock to drain unit. If water fails to drain vent the
unit manually by opening the temperature and
pressure relief valve.
` Open the cover(s) to the immersion heater
housing(s) and disconnect wiring from immersion
heater(s).
` Unscrew the immersion heater backnut(s) and
withdraw the immersion heater from the cylinder.
A key spanner is supplied with the product for easy
removal and tightening of the immersion heater(s).
Over time the immersion heater gasket may become
stuck to the mating surface. To break the seal insert a
round shafted screwdriver into one of the pockets on
the immersion heater and gently lever up and down.
Take care when lifting the immersion heater out of
the cylinder and work within safe working practices.
Carefully remove any scale from the surface of the
`
element(s).
CAUTION
DO NOT use a sharp implement as damage
to the element surface could be caused.
` Ensure sealing surfaces are clean and seals are
undamaged, if in doubt fit a new gasket. (spare
part number 95 611 822)
` Replace immersion heater(s), making sure not to
trap the gasket.
` Rewire, check, close and secure immersion heater
housing cover(s).
Re-commissioning
` Check all electrical and plumbing connections are
secure. Close the drain cock.
` With a hot tap open, turn on the cold water supply
and allow unit to refill.
` DO NOT switch on the immersion heater(s) or
boiler until the unit is full.
` When water flows from the hot tap allow to flow
for a short while to purge air and flush through any
disturbed particles.
` Close hot tap and then open successive hot taps in
system to purge any air.
` When completely full and purged check system for
leaks.
` The heating source (immersion heater(s) or boiler)
can then be switched on
Expansion vessel charge pressure
` Remove the dust cap on top of the vessel. Check
the charge pressure using a tyre pressure gauge.
The pressure (system de-pressured) should be
0.35MPa (3.5 bar). If it is lower than the required
setting it should be re-charged using a tyre pump
(schrader valve type). DO NOT OVER-CHARGE.
Re-check the pressure and when correct replace
the dust cap.
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