15
NOTE
You should ensure that one or two hot water
outlets are fully open during the above procedure.
This will ensure that the output of the appliance
(burner pressure) is not compromised due to a
high outlet temperature.
7.3.2
SETTING THE MINIMUM BURNER PRESSURE
Once the maximum burner pressure has been
checked and/or adjusted, remove one of the grey
wires from the modulating coil. Compare the
reading on the manometer with the value
described in 2.2. If adjustement is required, turn
the inner (red) cross-head screw clockwise to
increase, or counter-clockwise to decrease the
burner pressure, whilst ensuring that the outer
(10mm) nut does not move. When checking and/
or adjustement has been completed, isolate the
appliance from the electrical supply, replace the
protective cap, refit the compensator tube, refit
the grey wire to the modulating coil, remove the
manometer, and tighten the outlet test nipple.
IMPORTANT: A GAS SOUNDNESS CHECK
MUST BE CARRIED OUT.
7.4
EXTERNAL FAULTS
Before carrying out any fault-finding or component
replacement, ensure the fault is not attributable to
any aspect of the installation.
7.4.1
INSTALLATION FAULTS
7.5
ELECTRICAL CHECKS
Any electrical checks must be carried out by a
suitably qualified person.
7.5.1
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.
7.5.2
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.
Repeat above test on the Live & Earth connections
at the appliance term.
NOTE
Should it be found that the 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.
7.5.3
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. The meter should
read approximately 230V ac. If so proceed to
next stage. If not, see 7.5.4.
●
connect test leads between the Live & Earth
connections at the appliance. The meter should
read approximately 230V ac. If so proceed to
next stage. If not, see 7.5.4.
●
Connect test leads between the Neutral & Earth
connections at the appliance. The meter should
read approximately 0 – 15Vac. If so polarity is
correct. If not, see 7.5.4.
7.5.4
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.
7.5.5
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. 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.
7.6
FAULT FINDING
Before attempting any fault-finding, the electrical
checks as detailed in 7.5 must be carried out.
Isolate the appliance from the electrical supply
and remove the casing and PCB cover.
Restore the electrical supply to the appliance,
turn the selector switch to the “on” position, and
open a hot water outlet. The appliance should
now function as described in section 7.2. Should
the appliance fail to respond, the internal fuse
and connectors should be checked to ensure
Symptom
Possible causes
No ignition
Poor hot water
Unstable flame
picture
Check external wiring.
Check cold supply is connected to cold
inlet.
Check gas supply.
Check adjust flow rate.
Check flue system
