Unvented Hot Water Cylinder
- 31-
Cylinder sensor faulty
Check thermal cut out and replace if
faulty
Water flows from the expansion relief
valve when heating up
Dirt on the valve seat
Check and repair
PRV Faulty
Check an replace if faulty
Expansion vessel faulty
Check pressure, if insufficient re-
pressurise and replace if pressure not
held
Expansion relief valve faulty
Check if pressure is normal and
replace if faulty
Water flows from the temperature
and pressure relief valve when
heating up
Dirt in the valve seat
Check and repair
Boiler temperature control system
faulty
Check boiler control system and that
the 2 port valve switches when
cylinder temperature reached
Cylinder sensor faulty
Check sensor and TCO replace if
faulty
T & P relief valve faulty
If water escapes when only heated by
the immersion replace the T & P relief
valve
Immersion heater faulty
Check thermal cut out and replace if
faulty
