Issue 1 06/02/20
29
Maintenance
8
8.1.1 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.
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 heat source maintenance.
After any maintenance, please complete the relevant Service
Interval Record section of the Benchmark
8 Maintenance
8.1 General
8.2.1 Inspection
There is an inspection plate can be used as an access for
inspecting the cylinder internally.
8.2.2 Safety valve operation
• 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.
8.2 Standard Inspection & Maintenance Operations
See
See Checklist on page 38 and 39 of this document.
Caution
Water discharged may be very hot!
8.2.3 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.
