IDEAL LOGIC HIU Direct MT, Installation And Servicing, Page: 26 / 32

MAINTENANCE
26
LOGIC HIU -
Installation & Servicing / Users
B
52 MAINTENANCE
All maintenance procedures should be carried out by an
authorised technician.
Regular maintenance guarantees better efficiency and helps to
save energy.
Before carrying out any maintenance, repair or part replacement
work, proceed as follows:
• Switch off the electric supply
• Remove the cover
• Close the shut-off valves
• Empty the HlU using the drain cocks provided.
53 HEAT EXCHANGER REPLACEMENT
NOTE: Direction HHE is connected
• Remove the heat exchanger, loosening the 2 hex head
screws fixing it in place (A) - Remove to rear disengaging the
mounting studs
• Replace the heat exchanger and the O-rings - Refit new HHE
ensuring correctly located
• Tighten the two fixing screws (A).
NOTE: The pins fixing the heat exchanger are positioned
in such a way as to allow it to be placed only in the correct
direction.
A
A
54 STRAINER CLEANING
All HIU’s have a strainer on the inlet water from the centralised
heating system and for the Indirect HIU’s, a second strainer is
located on the secondary circuit.
To clean these strainers, carry out the following maintenance
procedure:
• Isolate electrics and primary valves
• Drain primary legs
• Unscrew the cap (B).
• Remove the st rainer mesh, flush thoroughly with clean
water to remove debris.
• Replace the strainer mesh - check the ring seal
• Screw the cap back into position - check for leak
• Turn on electric and valves
B
55 TEMPERATURE PROBE
REPLACEMENT
• Disconnect the probe cable, lightly folding the tab (C) and
extracting the connector
• Unscrew the probe
• Fit the new probe
• Reconnect the connector respecting the only possible way
it can be inserted.
56 REPLACING THE VALVE ACTUATOR
• Disconnect the actuator cable, lightly pressing the tab on
the connector and extracting it.
• Extract the fixing clip (D) and then the actuator.
• Position the new actuator (E).
• Insert the fixing clip, respecting the correct direction
• Reconnect the connector.
57 REPLACING THE VALVE OBTURATOR
• Disconnect the valve actuator (see previous paragraph).
• Disconnect feed pipe A
• Loosen grub screws B
• Slightly rotate whilst pulling body from mounting.
• Check “O” ring fitted.
• Refit new body tightening grub screws B and fit washer and
connect pipe A.
• Insert the actuator and fixing clip, respecting the correct
position
• Reconnect the electrical connector.
C
D
E
F
A