Technical data

Servicing
70 POTTERTON COMMERCIAL
120-393 632.4 04.08 Fh
10.7 Dismantling the heat exchanger
The following work has to be carried out, if the heat exchanger has
to be fully dismantled:
• The burner must have been removed.
• Close isolation valve of flow and return and drain boiler water.
• Loosen plugs of boiler sensors (flow and return).
• Loosen screw connectors of flow and return at the heat ex-
changer (flat seal).
• Pull off cable from water pressure gauge.
• Undo the joint threat of the pump replacement pipe and remo-
ve it.
• Remove return pipe.
• Pull off plug from gas valve, loosen and disassemble gas valve.
• Remove connection pipe between heat exchanger and conden-
sat sump.
• Push up the sliding sleeve of the flue gas pipe.
• Loosen nuts at condensat sump, remove yoke and dismantle col-
lecting tray.
• Remove air vent.
• Loosen nuts of holding sheet at the rear casing, lift heat ex-
changer from the rear casing and take out.
• For cleaning the heat exchanger, rinse with soft water jet (wit-
hout additives).
At the end of the maintenance work
• After finishing the cleaning work, re-install heat exchanger and
burner.
• Check the nominal heat load and flue gas values.
10.8 Check electrodes
Ignition electrodes
To avoid an influence of the ionisation current by the ignition
• The ignition electrode must only immerse into the edge of the
flame.
• The ignition spark must not spark-over to the ionisation electro-
de.
Installation position and electrode clearance has to be maintained
according to fig. 26
Ionisation electrode
The ionisation electrode must always be in contact with the flame.
During burner operation, the measured ionisation flow must not be
less than.
– At minimum power > 5 µA DC (switching threshold at 0.7 µA DC)
– At maximum power 10 µA DC
For measurements put the ionisation lead at spade connection at
ignition assembly and attach µA DC meter between them.
Caution! Do not touch plug contacts during the ignition process!