23
REPLACEMENT OF PARTS
To replace pump
• Drain down heating circuit of the boiler only, as de-
scribed previously.
Note:
It is not necessary to drain down entire heating
system to carry out this work.
• Undo two fixing screws and remove pump retaining
bracket from front of pump.
• Undo clips securing pump outlet hose connection to
pump.
• Slide hose along pipe to clear pump outlet.
• Disconnect pump electrical connection from PCB.
• Transfer automatic air vent to replacement pump us-
ing new washers supplied.
• Re-connect electrical connection to PCB.
• Fit replacement pump in reverse order to removal.
• Open isolating valves on flow and return connections,
refill, vent and pressurise boiler.
• Check for leaks.
To replace domestic hot water heat exchanger
• Drain down heating and hot water circuits of boiler
only as described previously.
Note:
It is not necessary to drain down entire heating
system to carry out this work.
• Unscrew and remove cold water inlet pipe from fix-
ing jig to water flow sensor.
• Supporting domestic heat exchanger, unscrew and re-
move two screws securing it onto pump mounting and
3-way valve/bypass housing.
• Remove heat exchanger from boiler.
• Fit replacement heat exchanger in reverse order to
removal using new seals, supplied.
Note
: Heat exchanger mounting screws are offset to
ensure correct fitting of replacement.
To replace 3-way valve head
• Locate 3- way valve in centre of lower controls area.
• Remove electrical plug from valve head.
• Pull out slotted metal clip from valve body and re-
move valve head from body.
• Fit replacement valve head in reverse order to re-
moval.
Note :
1)
When refiting clip, ensure that letters OK are as shown
in diagram 6.
2)
It is not necessary to drain boiler to carry out this work.
To replace 3-way valve/bypass housing
• Drain down heating and hot water circuit of boiler
only as described previously.
Note:
It is not necessary to drain down entire heating
system to carry out this work.
• Remove 3-way valve head as described previously.
• Remove domestic hot water heat exchanger as de-
scribed previously.
• Undo pipe connection from 3-way valve/bypass hous-
ing to primary heat exchanger, see diagram 7.
• Pull out slotted metal clips and remove bypass pipe.
• Pull out slotted metal clip and remove domestic pipe
from 3-way valve/bypass housing to storage vessel.
• Undo pipe from 3-way valve/bypass housing to fix-
ing jig.
• From underneath boiler, undo two screws securing
3-way valve/bypass housing and lift out of boiler.
• Fit replacement 3-way valve/bypass housing in re-
verse order to removal.
To replace system pressure sensor
• Drain down heating circuit of boiler only as described
previously.
Note:
It is not necessary to drain down entire heating
system to carry out this work.
• Locate system pressure sensor at front left hand side
of boiler, see diagram 8.
• Remove electrical connections from sensor.
• Pull off slotted metal clip and remove sensor from
boiler.
• Fit replacement sensor in reverse order to removal.
To replace gas valve module
• Locate gas valve module attached to side of gas valve.
Ins 063
Diagram 8
Diagram 6
Pho 375
➜
Mec 1
11
Diagram 7
Summary of Contents for ISOFAST F 28 E
Page 32: ...32 ...
