Xylem MOH2 Multi zone mixing module (obsolete) - Manual (Page 19)

19
Installation and operation manual MOH2
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Changing out the circulator
Preparation
• Caution: only a properly licensed electrician should disconnect and
reconnect the circulator.
• Remove electrical power even if you only want to clean the circulator
and not remove it.
• Close the ball valves 10 and 11 on the boiler feed and return side
• Connect the drain hose to the lower drain valve 13. In this way, the
check valve 7 will close automatically and the manifold will not drain
completely.
• Make sure that the drain hose can drain below the level of the circulator
pump
Draining of the water
• Open the drain valve 13
• When all water has drained, loosen the upper pump mounting screw to
allow air entry.
• Drain an additional 1/4 liter.
• Now the water should be below the level of the pump
Changing the circulator
• Remove both pump mounting screws.
• Take care when removing the pump since the rotor is only sitting loosely
on the ceramic ball and can fall out. Tilt the wiring end downward slightly
to prevent this.
• After removing the drive unit you can remove the rotor and clean it if
necessary.
• If the rotor have scratches in the lower part, the bearing has run out and
a new drive unit needs to be installed
• Have a properly licensed electrician disconnect the old circulator and
reconnect a new one.
• Before reassembly, carefully clean the seal ring and the housing.
• Reinsert the drive unit and tighten the two pump mounting screws
Restarting the system
• Refill unit by connecting the drain hose to a faucet. The air will bleed
through the automatic air purger.
• Open the valves on the boiler feed and return side
• Re-energize the unit
• The unit should be ready for operation