UK Manufactured Unvented Hot Water Cylinder Installation Guide
55
Fault
Possible Cause
Solution
Water escaping from the
case unit.
Compression fitting on hot - draw
off not sealing.
Check all factory and plumber connections inc T
and P and Immersion heater.
Cold water at hot tops.
Immersion heater not switched on
or cutout has triggered.
Check / reset.
Indirect - Boiler not working.
Check boiler - consult boiler manufactures’ instruc-
tions.
Indirect - motorized valve fault.
Check plumbing / wiring motorized valve.
Indirect - cutout in dual stat has
operated.
Check for faults in the thermostat or high limit stat
and reset.
Water discharges from
expansion relief valve
If continual - pressure reducing
valve (part of inlet control set ) may
not be operating correctly.
Check outlet pressure from inlet control set is 3 bar.
If continual - expansion relief valve
seat may be damaged.
Remove cartridge - check seat and renew if
necessary.
If intermittent - expansion vessel
charge may have reduced / bladder
perished.
Check pressure in expansion vessel. Recharge to 3
bar if necessary. If bladder perished replace vessel.
Unit is being back pressurized.
With cylinder cold check pressure in cylinder. If this
is the same as the incoming mains pressure then you
are getting backfeed. Install a balanced cold supply.
Water discharges from
temperature & pressure
relief valve
Unit has overheated - thermal
controls have failed.
Switch off power to boiler and immersion heaters.
Leave water supply on. Wait until discharge stops.
Isolate water supply and replace if faulty.
Milky / cloudy water
Oxygenated Water.
Water from any pressurized system will release
oxygen bubbles when flowing. The bubbles will
settle out.
No hot water flow
Cold main off.
Check and open stopcock.
Strainer blocked in pressure reduc-
ing valve.
Isolate water supply and clean.
Inlet control set may be fitted
incorrectly.
Check and refit if required.
Noise during hot water
draw off - typically worse in
the morning
Loose airing cupboard pipework.
Install extra clips.
Hot or warm water from
cold tap
If tap runs cold after a minute or so
the pipe is picking up heat from
heating pipework.
Insulate/re-route.
