E93.1001EN.C Manual CD
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17.2
Inspection & maintenance
Inspection, maintenance and the replacement of water heater parts should only be done by a skilled service engi-
neer. Apart from the maintenance proceedings it is advised to have a log chart for every water heater that describes
the following aspects:
•
Serial number
•
Date and time of maintenance
•
Name of maintenance engineer
•
Which parts were exchanged during maintenance
•
Which settings (software) were changed during maintenance
•
Special remarks / findings
•
Future aspects that need extra attention
•
Additional aspects: measurement reports, complaints by the (end)-user, lock-out codes, etc.
During maintenance the following parts and aspects of the water heater should be checked and inspected.
NOTICE: Before starting to work on the water heater:
•
Switch off the electrical power to the water heater (service switch and/or unplug water heater)
•
Close the gas valve to block gas supply to the water heater
Customer comments
Comments and remarks from the customer should be analysed and used to find possible causes for any occurring
problems and complaints.
Service history
The operational and fault history (total amount and since the last service) of the water heater can be retrieved with
the help of a computer, correct software and an interface cable. This information can be used to specify the mainte-
nance and service proceedings in relation to the water heater (parts).
Flue gas & air supply
The flue gas pipes and the air supply pipes must be checked for gas tightness. Also check if the mounting of these
pipes is correct, safe and not damaged. Check the rooftop of the water heater housing for signs of water leakage
and traces of water coming from the air supply pipe, the air vent or any condensate coming from the flue gas pipes.
Gas supply & safeties
The gas pipes must be checked for gas tightness. Also check if the mounting of these pipes is correct, safe and
not damaged. Any built in safeties should be checked for a correct functioning.
Remove complete burner unit
The complete burner unit consists of the fan, the burner plate and the internal burner. To remove this part for an
internal heat exchanger check: remove the 6 x M6 nuts and the ignition cable. After this take out the complete
burner unit by moving it forward out of the water heater housing. NOTICE: watch out for the burner plate insulation
that it won’t be damaged during this operation. While removing the complete burner unplug both of the electrical
and controlling cables of the fan. After all this, disassemble the air/gas mixing box on the suction side of the fan
and check the blade wheel of the fan.
Burner
Check the burner surface to see if it has damages, signs of oxidation and/or is cracked. When the burner surface
is damaged the burner must be replaced. The burner can be cleaned by using a soft
non-metallic
brush. The dust
can be removed with a vacuum cleaner or pressurized air.
Ignition / ionisation electrode
When the complete burner is removed, it is also very easy to check the ignition electrode. First check if the dis-
tances between the electrodes and between the electrode and the burner are according to the graph below. When
these are not correct, try to bend the electrodes in the right position. Notice: the electrodes undergo high temper-
atures, therefore the electrodes become hard and are difficult to bend. While being bent, used electrodes might
break or burst. Check the electrode, after bending, for any tear/crack and signs of oxide. When they are
burst/cracked or oxidised, replace the electrode. Also replace the electrode when there is a crack in the ceramic
insulation of the electrode. When the electrode is to be replaced, also the gasket should be renewed.
