DO NOT bypass the thermal cut-out(s) in any circumstances.
Operational faults
Operational faults and their possible causes are detailed in the Fault Finding
section of this book. It is recommended that faults should be checked by a
competent Installer.
The air volume within the expansion vessel will periodically require recharging
to ensure expanded water is accommodated within the system. A discharge
of water INTERMITTENTLY from the expansion valve will indicate the
air volume has reduced to a point where it can no longer accommodate the
expansion. This will require a suitably qualified person to check the expansion
vessel pressure and no attempt should be made to re-pressurize the expansion
vessel by the end user.
page 24
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 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
