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6. OSO FAULT FINDING GUIDE
No water from
hot taps
Water from taps
is cold
Intermittent
water discharge
Continous
water discharge
Mains supply off
Strainer blocked
Immersion heaters
not switched on
Cylinder thermal
cutout has
operated
Immersion heater
thermal cutout has
operated
Reduced expansion
vessel charge
Thermal control
failure (note: water
will be hot
Expansion relief
valve not working
properly
Cold water inlet
pressure reducing
valve not working
Temperature and
pressure relief valve
faulty
Check and open stopcock
Turn off water supply, remove and clean strainer
Check and switch on
Check and press reset button
Check and press reset button
Follow instructions 5.2 Intermittent or slow discharge
from tundish
Switch off power to immersion heater(s). When dis-
charge has stopped check thermal controls, replace if
faulty
Check and replace if faulty
Check pressure from valve, if greater
than 3 bar - replace
Drain 10 litres from cylinder and replace valve
