Heatrae Sadia Megaflo Eco 125DD, Manual

Page: 27 / 40

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10. Troubleshooting
`
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.
The fault finding chart (table 7, below) will enable
operational faults to be identified and their possible
causes rectified. Any work carried out on the unvented
water heater and its associated controls MUST be
carried out by a competent installer for unvented water
heating systems. In case of doubt contact service
support.
Spare Parts
A full range of spare parts are available for the
cylinder range (Table 8, 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.
Table 7: Fault finding chart
WARNING
Do not tamper with any of the safety valves
or controls supplied with the cylinder as this
will invalidate any guarantee.
10.1 Fault finding
Important
`
After servicing, complete the relevant Service
Interval Record section of the Benchmark Checklist
located on pages 35 of this document.
`
Servicing should only be carried out by competent
persons in the installation and maintenance of
unvented water heating systems.
`
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.
Fault Possible cause Remedy
No hot water 1. Mains water supply off. 1. Check and open stop cock.
2. Strainer blocked. 2. Turn off water supply. Remove strainer and clean ( see page
31).
3. Cold water combination valve
incorrectly fitted.
3. Check and refit as required.
Water from hot taps
is cold
1. Back up immersion heater not
switched on.
1. Check and switch on.
2. Back up immersion heater
thermal cut-out has tripped.
2. Check. Reset by pushing button (Figure 14, page 20).
3. Indirect programmer set to
central heating only.
3. Check. Set domestic to a hot water programme.
4. Indirect boiler not working. 4. Check boiler operation. If fault is suspected consult boiler
manufacturers instructions.
5. Indirect thermal cut-out has
tripped.
5. Check. Reset by pushing button. Check operation of indirect
thermostat (Figure 14, page 20).
6. Indirect motorised valve not
connected correctly.
6. Check wiring and/or plumbing connections to motorised
valve (see Figures 16&17, page 21).
Water discharges from
expansion relief valve
1. Intermittently. Air volume in the
cylinder has reduced
1. See page 26 for details on how to test and recharge.
2. Continually. 3 bar pressure
reducing valve is not working
correctly.
2. Check pressure from 3 bar pressure reducing valve. If greater
than 3 bar replace pressure reducing cartridge.
3. Continually. Expansion valve seat
damaged.
3. Remove expansion relief cartridge from 8 bar pressure relief
valve and check seating, if necessary fit new cartridge.
Water discharges
from the T&P valve
intermittently
1. Air volume in the cylinder has
reduced
1. See page 26 for details on how to test and recharge.
2. 8 bar expansion relief valve
faulty.
2. Check valve and replace if necessary
Water discharges
from the T&P valve
continually
1. Thermal control failure. Note
water will be very hot.
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.
Milky water 1 Oxygenated water. 1. Water from a pressurised system releases oxygen bubbles
when flowing. The milkiness will disappear after a short while.