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Installation and Servicing
SECTION 3 - SERVICING
3.4 HIU FRONT PANEL REMOVAL / REPLACEMENT
REMOVAL
1. Pull open the door panel.
2. Remove the two screws retaining the front
panel on the bottom edge – retain screws.
3. Pull front panel forward from the bottom and
lift away to disengage from top retention.
REPLACEMENT
1. Hook the front panel onto the top panel of the
HIU, ensure panel is engaged.
2. Push panel against control panel and insert
the two retaining screws.
3. Re-tighten the two retaining screws.
4. Close door panel up until engaged.
Note: For removal of insulation and retting refer
to Section 3.12.
3.5 DRAINING THE HEAT INTERFACE UNIT
IMPORTANT: The primary circuit must only
be drained with the permission of the Heat
Network service provider.
1. Isolate the appropriate circuit by turning the isolation
valves to the off/drain position (handle horizontal).
WARNING – If draining the primary circuit, both ow
and return isolation valves MUST be isolated. Failure
to do this will subject the drain point to system pressure
when opened and cause the full system to be drained.
NOTE, INDIRECT UNITS ONLY: Before isolating the
DCW supply, the lling loop must be connected with the
in line valve turned to the off position. See Section 2.4.
The DCW & central heating circuits cannot be drained
via the isolation valve.
DCW: The drain point on the front of the DCW manifold
should be used.
CH: The drain point on the underside of the waterset
should be used.
2. Connect a hose to the applicable drain point nozzle
and route to a container.
3. Slowly open the applicable drain point using the central
screw. Care MUST be taken while releasing pressure
within the circuits, particularly the primary.
4. Slowly open the applicable vent point to improve the
ow of uid from the circuit.
5. Once the ow of uid has stopped, close the drain
point(s) and air vent(s).
2
DCW INLET
DHW OUTLET
PRIMARY RETURN
PRIMARY FLOW
CH FLOW
CH RETURN
PRV
FILLING
LOOP
Indirect shown
Valve shown open
SERVICING
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