VOKERA Hydra Installation & Servicing Instructions Manual - page 29
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7.8
DIAGNOSTIC RECALL
In addition to displaying a fault code, the appliance
memorises the operating conditions at the time of
lockout, this information can be recalled and
displayed using the following procedure:
●
access the appliance service mode as detailed
in section 7.3
●
press the
mode
button until “ERRO” appears
in the display
●
press the
S
button to recall the information
as detailed below
●
press the
mode
button to exit Error mode
●
press the
reset
button to exit the appliance
service mode.
7.9
CHECKING THE EXPANSION VESSEL
Carry out the component removal procedure as
described in section 6.4. You must ensure that
the boiler is completely drained of water.
Using a suitable pressure gauge, remove dust
cap on expansion vessel and check the charge
pressure. The correct charge pressure should be
1.0 bar
±
0.1 bar. If the charge pressure is less,
use a suitable pump to increase the charge.
Please note, you must ensure the safety valve is
in the open position whilst re-charging takes
place. Replace the dust cap and carry out the
relevant commissioning procedure.
7.10
EXTERNAL FAULTS
Before carrying out any fault-finding or component
replacement, ensure the fault is not attributable
to any aspect of the installation.
For example, external wiring fault, service valves
closed, gas supply turned off, etc. The table
below may assist in identifying some common
installation faults.
7.11
ELECTRICAL CHECKS
Any electrical checks must be carried out by a
suitably qualified person.
7.11.1 EARTH CONTINUITY TEST
Isolate the appliance from the electrical supply,
and using a suitable multi-meter carry out a
resistance test. Connect test leads between an
appliance earth point and the earth wire of the
appliance supply cable. The resistance should
be less than 1 ohm. If the resistance is greater
than 1 ohm check all earth wires and connectors
for continuity and integrity.
7.11.2 SHORT CIRCUIT CHECK
Isolate the appliance from the electrical supply,
and using a suitable multi-meter, carry out a short
circuit test between the Live & Neutral connections
at the appliance input board (fig.14).
Repeat above test on the Live & Earth connections
at the appliance input board (fig.14).
NOTE
Should it be found that a fuse has failed but no
fault is indicated, a detailed continuity
Check will be required to trace the fault. A visual
inspection of components may also assist in
locating the fault.
7.11.3 POLARITY CHECK
With the appliance connected to the electrical
supply and using a suitable multi-meter, carry out
the following voltage tests:
●
connect test leads between the Live & Neutral
connections at the appliance input board (fig.14).
The meter should read approximately 230V ac.
If so proceed to next stage. If not, see section
7.11.4.
●
connect test leads between the Live & Earth
connections at the appliance input board (fig.14)
the meter should read approximately 230V ac.
If so proceed to next stage. If not, see section
7.11.4.
●
connect test leads between the Neutral & Earth
connections at the appliance input board (fig.14)
the meter should read approximately 0 – 15Vac.
If so polarity is correct. If not, see section
7.11.4.
7.11.4 REVERSED POLARITY OR SUPPLY FAULT
Repeat the above tests at the appliance isolator,
if testing reveals correct polarity and/or supply at
the isolator, re-check wiring and connections
between the isolator and the appliance.
If tests on the isolator also reveal reversed polarity
or a supply fault, consult the local electricity
supplier for advice.
7.11.5 RESISTANCE TO EARTH CHECK
Isolate the appliance from the electrical supply,
and using a suitable multi-meter carry out a
resistance test. Connect test leads between the
Live & Earth connections at the appliance input
board (fig.14). If the meter reads other than
infinity there is a fault that must be isolated, carry
out a detailed continuity check to identify the
location of the fault.
IMPORTANT
These series of checks must be carried out
before attempting any fault-finding procedures
on the appliance. On completion of any task that
required the disconnection and re-connection of
any electrical wiring or component, these checks
must be repeated.
1
st
digit
shows
1
2
3
4
5
6
Right display
shows
Most recent fault code
Appliance status at time of fault
Flow sensor temperature at time of fault
Return sensor temperature at time of fault
Inlet sensor temperature at time of fault
External sensor temperature at time of fault
Fault code
displayed
E 02
b/E 18
E 36
E 37
E 38
Possible cause
Gas turned off
Air in gas pipe
Insufficient gas
Pump seized
Flow/return service valve closed
Flow sensor cable disconnected
Return sensor cable disconnected
Cold water inlet sensor cable disconnected