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10. Troubleshooting
WARNING
Do not tamper with any of the safety valves
or controls supplied with the cylinder as this
will invalidate any warranty.
Water contained in the cylinder may be
very hot, especially following a thermal
control failure. Caution must be taken
when drawing water from the unit.
NEVER bypass any thermal controls or
operate system without the necessary
safety valves.
10.1 Fault finding
Important
Servicing should only be carried out by competent
`
persons in the installation and maintenance of
unvented water heating systems.
Table 6: Fault finding chart
Fault
No hot water
Water from hot taps
is cold
Water discharges
from expansion relief
valve
Water discharges
from the T&P valve
intermittently
Water discharges
from the T&P valve
continually
Milky water
Possible cause
1. Mains water supply off.
2. Strainer blocked.
3. Pressure reducing valve
incorrectly fitted.
1. Immersion heater not switched
on.
2. Immersion heater thermal cut-
out has tripped.
3. Indirect programmer set to
central heating only.
4. Indirect boiler not working.
5. Indirect thermal cut-out has
tripped.
6. Indirect motorised valve not
connected correctly.
1. Intermittently. Air volume in the
cylinder has reduced
2. Continually. 3 bar pressure
reducing valve is not working
correctly.
3. Continually. Expansion valve
seat damaged.
1. Air volume in the cylinder has
reduced
2. 8 bar expansion relief valve
faulty.
1. Thermal control failure. Note
water will be very hot.
1 Oxygenated water.
After servicing, complete the relevant Service
`
Interval Record section of the Benchmark Checklist
located on page 35 of this document.
Any spare parts used MUST be authorised parts.
`
Disconnect the electrical supply before removing
`
any electrical equipment covers.
NEVER bypass any thermal controls or operate
`
system without the necessary safety valves.
The fault finding chart (Table 6, below) will enable
operational faults to be identified and their possible
causes rectified. Any work carried out on the unvented
appliance and its associated controls MUST be carried
out by a competent installer for unvented water heating
systems. In case of doubt contact customer
(see page 40 for
details).
Spare Parts
A full range of spare parts are available for the cylinder
range (Table 7, page 29). Refer to the technical data
label on the unit to identify the model installed and
ensure the correct part is ordered. You will need to
quote the serial number, which is printed on the data
label.
1. Check and open stop cock.
2. Turn off water supply. Remove strainer and clean (see
page 25 for details).
3. Check and refit as required.
1. Check and switch on.
2. Check. Reset by pushing button (see Fig. 12, page 20).
3. Check. Set programmer to a hot water programme.
4. Check boiler operation. If fault is suspected consult boiler
manufacturers instructions.
5. Check. Reset by pushing button. Check operation of
indirect thermostat (see Fig. 13, page 20).
6. Check wiring and/or plumbing connections to motorised
valve (see Fig. 14 & 15, page 21).
1. See page 26 for details on how to test and recharge.
2. Check pressure from 3 bar Pressure Reducing Valve. If
greater than 3 bar replace Pressure Reducing Valve.
3. Replace combined T&P/Expansion relief valve assembly
1. See page 26 for details on how to test and recharge.
2. Check valve and replace if necessary
1. Switch off power supply to immersion heater(s) and shut
down the boiler. DO NOT turn off the water supply. When
discharge stops check all thermal controls, replace if faulty.
1. Water from a pressurised system releases oxygen bubbles
when flowing. The milkiness will disappear after a short
while.
Remedy
service.
27
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