7.8
HEAT EXCHANGER
(Fig. 5.7.2 item 42)
i)
Isolate the appliance (Section 7.1)
ii)
Gain access (Section 7.2)
iii)
Shut of the water supply to the appliance.
iv)
Remove the burner head (Section 7.7)
v)
Drain the system to below the level of the appliance using the drain off tap at the
base of the heat exchanger.
vi)
Remove the front control panel (Section 7.2 (iii))
vii)
Remove the boiler thermostat (Section 7.4.2)
viii)
Remove the push on connectors to the water pressure switch, flow overheat
thermostat, flow high limit thermostat and flue protection thermostat taking note of
the correct positions.
ix)
Remove the condensate trap (Section 7.10)
x)
Remove the pressure gauge phial located next to the drain off tap.
xi)
Remove the air filter (Section 7.9)
xii)
Remove the two springs connecting the bottom tray of the air filter with the
cabinet top cover.
xiii)
Disconnect the flow and return connections to the boiler.
xiv)
Remove the push on flue and air connections to the flue and air pipes exiting the
top of the boiler.
xv)
Remove the four screws fixing the cabinet top cover to the cabinet body and
remove the top cover.
xvi)
Remove the nut fixing the strap retaining the base of the heat exchanger and pull
out the strap by unhooking it from its fixing behind the heat exchanger.
xvii)
Remove the allen screw securing the top of the heat exchanger to its mounting
bracket.
xviii)
Remove the heat exchanger, with pipework attached.
xix)
Remove the flow, return and flue pipework from the heat exchanger
(Replacement heat exchangers are supplied with return pipework attached).
xx)
Reassemble (Section 7.3)
xxi)
Recommission (Section 4 - Commissioning)
7.9
AIR FILTER
(Fig. 5.7.4 item 19)
i)
Isolate the appliance (Section 7.1)
ii)
Gain access (Section 7.2)
iii)
Drop the lower section of the air filter housing by releasing the toggle clip.
iv)
Open the lower section as far as possible and pull out the combined paper filter
element with rubber seal.
v)
Reassemble (Section 7.3)
NB:
When fitting the new air filter take care to ensure that the new filter is
placed to cover completely the air intake into the boiler cabinet.
7.10
CONDENSATE TRAP
(Fig. 5.7.2 item 58)
i)
Isolate the appliance (Section 7.1)
ii)
Gain access (Section 7.2)
iii)
Disconnect the condensate line from the base of the heat exchanger.
iv)
Disconnect the condensate line from the base of the flue assembly.
v)
Disconnect the condense lines from the projection of the condensate trap from
the base of the cabinet.
vi)
Withdraw the condensate trap.
vii)
Mop up any spilled condensate.
viii)
Reassemble (Section 7.3)
NB:
When re-fitting the condensate trap pour water onto the condensate hose
from the base of the heat exchanger until nearly full. Then reconnect the
condensate hose to the base of the heat exchanger.
WD51/2/1997 Chapter 7 : Replacement Of Parts
The Keston 170 Condensing Boilers
Installation & Servicing Instructions
Page : 46
