Glow-worm Ultracom sxi - Manual (Page 58)

58
15 Replacement of Parts
BYPASS
TUBE
RH
HYDROBLOCK
LH
HYDROBLOCK
CH OUTLET
PIPE
SECURING
SCREW
PRIMARY
FLOW PIPE
SPIGOT (4 OFF)
MOUNTING
BRACKET
BLANKING PLATE
RUBBER SEAL
(4 OFF)
BLANKING
PLATE
AUTOMATIC
BYPASS
HOUSING
SEALS
CH FILTER
(in Hydroblock)
RETAINING
CLIP
RETAINING
CLIP
Diagram 15.17
13531
15.22 Hydroblock and Bypass Tube
For access, refer to section 15.1.
IMPORTANT: To replace the bypass tube the LH and RH
hydroblocks will need to be removed. The following procedure
must also be used for the replacement of either the LH or RH
hydroblock.
Drain the boiler heating circuit as described in the appropriate
section of 15.1.
Isolate the gas supply at the gas service isolation valve, see
diagram 12.1.
Remove the low water pressure sensor from the LH
hydroblock, refer to section 15.20.
Remove the blanking plate, see diagram 15.17.
Remove clips from the plastic LH hydroblock retaining the
primary flow pipes and CH outlet pipe, see diagram 15.17.
Remove the primary flow pipe from the LH hydroblock.
Remove the CH filter from the primary flow pipe port in the LH
hydroblock. The filter is a push-fit in the hydroblock port.
Undo the union nuts on the CH outlet pipe and gas pipe at the
connections between the top and bottom modules.
Undo the locknuts retaining the CH outlet pipe and the gas
pipe to the boiler chassis.
Rotate the gas pipe upwards and clear of the chassis panel.
Remove the 3 screws which retain the automatic bypass
housing, refer to section 15.21.
Grip the LH and RH hydroblocks simultaneously and lift clear
of the spigots on the mounting bracket. The RH hydroblock
should be drawn upwards past the plastic three way valve
body.
NOTE: Before removing the bypass tube from the
hydroblocks, take note of the tube position and orientation.
Fit the new bypass tube with new ‘O’ ring seals and re-
assemble to hydroblocks.
NOTE: Before lowering the assembly onto the bracket
spigots, ensure that the two port axis in each hydroblock run
parallel to each other and also that the bottom faces of the
hydroblocks are level and aligned.
Lower the assembly onto the bracket ensuring that the brass
washers on the DHW and DCW pipes are not displaced.
Check also that the seals on the front of the RH hydroblock
remain in place as it slides past the automatic bypass
housing. Before refitting the plate to plate heat exchanger
ensure that the four rubber seals are in place, two in the LH
and two in the RH hydroblock.
Fit new ‘O’ rings to pipes.
Refill system, vent and pressurise the boiler.