61
ecoTEC plus 937 installation and maintenance manual
9.6
Replacing the expansion vessel of the shift
load storage tank
1
2
Fig. 9.7 Replacing the expansion vessel of the shift load
storage tank
d
Danger!
Before replacing components ensure that the
safety instructions from Section 9.1 are
observed.
• Disconnect the appliance from the mains as described
in Section 9.1, and close the gas isolation valve in the
gas supply pipe.
• Close the cold water inlet isolation valve.
• Open a hot water tap in order to release the pressure
on the water circuit. Then close the tap again.
• Remove the screw on the cover of the shift load
storage tank.
• Remove the cover.
• The expansion vessel (
1
) is freely accessible
• Release the nuts (
2
) on the expansion tank.
• Pull the expansion tank (
1
) off the pipe fitting and
remove it from the EPS trough.
• Insert the new expansion tank in the EPS trough.
• Re-connect the new expansion tank. Use a new gasket:
• Check the pressure of the expansion tank (minimum
pressure 4 bar).
• Filling and vent the combi boiler and the shift load
storage tank.
• After completion of the work check the system for gas
leaks and carry out a function test (see Section 7.8).
9.7
Replacing the storage tank pump of the shift
load storage tank
2
1
5
4
3
6
Fig. 9.8 Replacing storage tank pump
d
Danger!
Before replacing components ensure that the
safety instructions from Section 9.1 are
observed.
• Isolate the unit from the mains as described in
Section 9.1.
• Close the gas isolation valve in the gas supply pipe.
• Close the isolation valves in the hot water system and
drain the water out of the combi boiler and the shift
load storage tank.
• Remove the discharge pipe (
1
) of the heating pressure
relief.
• Lower the electronics box as described in
Section 4.19.2.
• Unclip the back cover of the electronics box and swing
the cover upwards to reveal the connections.
• Pull the plug
X12
off the electronic printed circuit
board.
• Pull the free end of the line carefully through the
entry grommets on the combi boiler and on the shift
load storage tank.
• Release the sensor wire of the pump from the wiring
harness by pulling the plug off the wiring harness.
• Unscrew the sheet metal bracket (
6
) from the chassis.
• Release the fitting (
2
) on the connector pipe (
3
).
Replacing components 9
