Fault Finding; User Instructions - Dimplex SCx175sd Installation And Operation Manual

10.9. In hard water areas it may be necessary to remove and de-scale the immersion heater element.
Replace the gasket each time it is removed. If large amounts of scale is present it may be advisable
to fit a water softening device.
10.10. To refill the cylinder, close the drain cock, disconnect the hose, refit the immersion heater with
new gasket 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.
10.11. 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.
10.12. Finally switch on the mains electricity supply to the immersion heater and the solar system.
Turn the system on to heat the water. As the system heats up, check again for any leaks and rectify
as necessary.

11 Fault finding

Notice: Disconnect electrical supply before removing any electrical equipment cover.
Fault
No hot water
Water from hot taps is cold
Intermittent water discharge through
tundish on warm-up
Continuous water discharge
12 Users instructions
12.1 Your SCX Solar unvented hot water cylinder has been designed to give many years of trouble
free service and is made from hygienic stainless steel. It includes a 3 kW electric immersion heater
(and an auxiliary coil for boiler connection – indirect models only) which heats the water to 60
pre-heating from the solar system is completed.
Possible cause
1. Mains supply off
2. Strainer blocked
3. Pressure reducing valve(PRV) fitted the
wrong way
1. Programmer set to heating only or not
switched on for hot water
2. Central heating boiler malfunction
3. High limit thermostat has tripped
4. Pump malfunction
1. Expansion vessel has lost its charge
pressure
1. Pressure reducing valve (PRV) not
working
2. Pressure relief valve not seating correctly
3. Temperature and pressure relief valve not
seating correctly
Remedy
1. Open stopcock
2. Turn water supply off, remove strainer
and clean. (see 10.6)
3. Re-fit with arrow pointing in direction of
flow
1. Set programmer to call for hot water
2. Check boiler operation if faulty consult
your boiler manufacturers instructions
3. Check and re-set
4. Check wiring and/or plumbing
connections to pump
1. Turn off stopcock open a hot water tap
check vessel charge pressure and recharge
to 3 bar
2. Replace vessel if necessary
1. Check pressure from PRV if greater than
3bar replace cartridge
2. Manually lift the valve once or twice to
clear any debris from the seat otherwise
replace valve
3. Manually lift the valve once or twice to
clear any debris from the seat otherwise
replace valve
o
C once
13