27
Troubleshooting
Fault
Cause
Solution
A No water from hot
water taps
A.1 Stop valve closed
A.2 Strainer blocked
A.3 Pressure reducing valve
fitted against flow
A.1 Open stop valve
A.2 Turn water supply off, clean
strainer and re-commission
A.3 Re-fit with arrow showing in
direction of flow
B Intermittent water
discharge through
tundish on warm-up
B.1 Expansion vessel lost
charge
B.1 Check expansion vessel (see
commissioning/maintenance),
top-up or replace
C Continuous discharge
C.1 Pressure reducing valve
not working
C.2 Pressure relief or T&P
valve not seating
correctly
C.3 Malfunction of high limit
thermostat or appliance
C.1 Check pressure after valve and
replace if faulty
C.2 Manually lift valve once or twice to
clear debris, otherwise replace
C.3 Check function of thermostats
and appliances
D Leakage from casing
D.1 Compression/threaded
joints not formed
correctly
D.1 Re-seal joints with care
E Hot water from cold tap
E.1 Hot pipework being
routed adjacent to cold
pipework.
E.2 Leaking seal in mixer tap
E.1 Insulate hot pipework or re-route
E.2 Replace seals in mixer tap
F Metallic noise from
system
F.1 Pipework not sufficiently
supported
F.1 Add extra pipework fixings
G Humming noise from
system during re-heat
G.1 Air in system
G.2 Flow rate well in excess
of specification
G.1 Bleed system thoroughly and
re-pressurise
G.2 Reduce pump speed
H Cylinder not charging
H.1 Power supply turned off
H.2 Tariff not set correctly
H.3 Temperature set-point
not set correctly
H.4 Direct heating
malfunction
H.5 Direct heating high limit
thermostat has tripped
H.1 Ensure both power supplies are
turned on
H.2 Set tariff correctly (Section 7.2.1)
H.3 Set Primary Set-point
(Section 11.2.4)
H.4 Call for qualified person to check
immersion heater
H.5 Reset limit thermostat(s) and
inform installer
I The water in the
cylinder is too hot
I.1 Primary/Boost
temperature set point is
too high
I.2 Hygiene mode overriding
primary set-point
I.3 Temperature sensors
faulty or not installed
correctly
I.1 Check/Adjust the primary and
boost temperature set-points
(Section 11.2.4)
I.2 Check/Adjust the Hygiene Set
point (Section 7.2.2)
I.3 Check temperature displayed
for accuracy (Section 11.2.6),
if clearly incorrect contact
seller
J Hot water runs out
during the day
J.1 Cylinder not storing
enough energy to meet
daily requirements
J.2 Increased usage resulted
in hot water ran out
earlier than usual
J. 1 Raising the Primary set-point in
order to store additional energy
during the off peak period (Section
11.2.4)
J.2 Boost function heats a small
volume of water (Section 11.2.5)
13 Troubleshooting
Summary of Contents for IOT Series
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