12
7.7.
Check the charge pressure in the expansion vessel and top up as necessary. The charge
pressure should be 0.15 or 0.3 MPa.
7.8.
Close the drain cock, disconnect the hose, refit the heating element and close all hot water
taps before reopening the stopcock. Allow the cylinder time to fill whilst checking for any leaks.
Release any air from the system by opening each hot water tap individually, starting with the one
furthest from the cylinder.
7.9.
Manually lift the expansion relief and temperature and pressure relief valve one at a
time, every 12 months (more frequently in hard water areas) to prevent debris from building
up behind the valve seat. Whilst carrying out this operation, check that the discharge to waste
is unobstructed. Check that each valve seals correctly when released. As the valves are pre-
calibrated, they require no further maintenance.
7.10.
Finally, when the heater is full of water switch on the mains electricity supply to the water
heater. As the system heats up, check again for any leaks and rectify as necessary.
7.11.
In the event of the manual reset cut-out operating, isolate the heater from the mains supply,
investigate and identify the cause of the operation of this cut-out, rectify the fault before manually
resetting the cut-out via the reset button on the cut-out. Finally switch the mains electricity
supply back on.
8. FAULT FINDING
Notice: Disconnect electrical supply before removing any electrical equipment cover.
FAULT
POSSIBLE CAUSE
REMEDY
No hot water
1.
Mains supply off
2.
Strainer in pressure reducing
valve blocked
3.
Pressure reducing valve
incorrectly fitted
1.
Open stopcock
2.
Turn water supply off, remove
strainer and clean.
3.
Re-fit correctly
Water from hot taps is cold
1.
Programmer if fitted is not
switched on.
2.
High limit thermostat has tripped
1.
Switch on the programmer
2.
Check and re-set
Intermittent water discharge
through tundish on warm-up
1.
Expansion vessel has lost its
charge pressure
1.
Turn off stopcock, open a hot
water tap, check vessel charge
pressure and recharge
Continuous water discharge
1.
Pressure reducing valve not
working
2.
Expansion relief valve not seating
correctly
3.
Temperature and pressure relief
valve not seating correctly
1.
Check pressure from Pressure
reducing valve if greater than 0.3
MPa replace cartridge
2.
Manually lift the valve once or
twice to clear any debris from the
seat otherwise replace valve
