25
Fault finding
The Fault Finding chart will enable operational faults to be identified and their possible causes
rectified. Any work carried out on the
Andrews Flexistor 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 the Andrews Flexistor Service Department.
Fault
Possible Cause
Remedy
No hot water flow
Mains water supply off
Check and open stop cock/isolating valve
Strainer blocked
Turn off water supply, remove strainer and clean
Cold water combination valve incorrectly
fitted
Check and refit as required
Water from hot tap
is cold
Auxiliary immersion heater not switched
on
Check and switch on
Auxiliary immersion heater thermal cut-
out has operated
Check, reset by pushing button on thermal cut-
out
External heat source not switched on
Check, turn on external heat source
External heat source not working
Check heat source operation. If fault is suspected
consult heat source manufacturer’s instructions
External heat source thermal cut-out has
operated
Check, reset by pushing button on thermal cut-
out
Check operation of heat source thermostat
Water discharges
from overflow visual
indicator (tundish)
INTERMITTENTLY
Incorrect pre-charge pressure for expansion
vessel
CONTINUALLY
Check pressure from pressure reducing valve
Remove expansion relief cartridge from pressure
relief valve and check seating. If necessary fit
new cartridge
Water discharges
from the T&P relief
valve intermittently
Expansion relief valve faulty
Check valve and replace if necessary
Water discharges
from the T&P relief
valve continually
Thermal control failure
NOTE: Water will be very hot
Switch off power to immersion heater(s) and
shut down external heat source. DO NOT turn
off water supply. When discharge stops check all
thermal controls, replace if faulty
Performance has
deteriorated
GRADUALLY
Check for scale build up in the DHW heat ex-
changer
Table 11 - Fault finding guide.
Servicing
Important
i) Servicing should only be carried by an authorised Engineer, Agents or by installers competent in
the installation and maintenance of unvented water heating systems.
ii) Any spare parts used MUST be authorised Andrews Flexistor parts.
iii) Disconnect the electrical supply before removing any electrical equipment covers.
iv) NEVER bypass any thermal controls or operate system without the necessary safety valves.
v) Water contained in the Andrews Flexistor unit may be very hot, especially following a thermal
control failure. Caution must be taken when drawing water from the unit.
Summary of Contents for Flexistor 1000
Page 30: ...30 38 Part No 95 607 690 46 Part No 95 980 009 2 1 34 1 46 ...
Page 31: ...31 48 38 30 38 31 32 ...
Page 32: ...32 ...
Page 33: ...33 ...
