13
10.1
Fault finding
Disconnect the electrical supply before removing the
terminal cover. It is recommended that any service
operations on the product are carried out by a
competent person.
10. Troubleshooting
WARNING
Do not tamper with any of the safety valves
or controls supplied with the cylinder as
this will invalidate any guarantee
Symptom
Possible cause
Remedy
Water not heating
A. Electrical supply fault
A. Check electrical supply
B. Thermal cut-out tripped
B. Check cut-out, if operated reset and check
thermostat operation. If necessary replace
thermostat/thermal cut-out (see wiring diagram)
C. Thermostat fault
C. Check thermostat operation. Replace if
necessary
Discharge of water
from pressure relief
valve (continuously)
Excessive mains water pressure
Fit Pressure reducing valve Pack U1 and U2
(see important installation points)
Discharge of water
from Pressure relief
valve (intermittently)
A. Expansion in mains not
possible
A. Fit pack U2 (see important installation points)
B. Mains pressure exceeds 0.41
MPa (4.1 bar)
B. Fit packs U1 and U2
C. Pack U1 fitted without pack U2
C. Fit pack U2 when using pack U1
D. Pressure relief valve fault
D. Replace pressure relief valve
E. Loss of pressure from
expansion vessel
E. Check and if necessary re-charge Expansion
vessel pre-charge pressure (see section 9)
Discharge of water
from Temperature /
pressure relief and/
or water/steam from
pressure relief valve
Thermostat and thermal cut-out
fault
Replace thermostats and thermal cut-outs
No water flow
A. Inlet vales incorrectly fitted
A. Check all vales are correctly installed in
accordance with flow direction arrows
B. Mains water supply not turned
on
B. Check mains water supply is on
C. Blockage in mains water
supply
C. Check for obstructions. If pack U1 is fitted
check the strainer is not blocked
'Milky water'
Oxygenated water
Water from a pressurised system releases
oxygen bubbles when flowing. The milkiness will
disappear after a short while
