4.15 Replacement of Immersion Heater and Immersion Heater Combined Thermostat/Thermal
Cut-out
The cylinder must be fully drained prior to removing the immersion heater. Refer to Section 2.
8
for the procedure to drain the
unit.
1
.
Important: Ensure ALL power supplies are isolated before starting work on the boiler
.
P
erform the actions detailed in section 4.
1
General Access.
Note:
only the two lower front panels need be removed for this servicing action, follow instructions 3 and 4 for how to
remove these panels.
2.
Remove the immersion heater cover by removing the securing nut and pulling the cap away from the cylinder.
3.
Disconnect the electrical supply cable from the thermostat and the earth post assembly. Remove the thermostat from
the immersion heater by carefully pulling outwards. DO NOT twist the thermostat as damage to the connections to the
immersion heater may occur.
4.
To remove the immersion heater unscrew the brass bac
k
nut using the
k
ey spanner supplied with the unit. Retain the
bac
k
nut. Over time the immersion heater gas
k
et may become stuc
k
to the mating surface. To brea
k
the seal insert a
round bladed screwdriver into one of the poc
k
ets on the immersion heater and gently lever up an down.
5
.
Withdraw the immersion heater from the cylinder.
Note:
the immersion heater is curved downwards 90 degrees to reach the base of the cylinder. When removing, the
head of the immersion heater should be tilted towards the floor for ease of withdrawal.
6.
Insert the immersion heater into the boss ensuring the right angled element hangs vertically downwards towards the
base of the unit.
P
ush the immersion heater mounting plate into the boss so the gas
k
et seats on the flange at the
base of the boss. It may be helpful to support the immersion heater using a round bladed screwdriver inserted into
one of the poc
k
ets on the immersion heater whilst the brass bac
k
nut is tightened. Tighten the brass bac
k
nut using the
k
ey spanner supplied.
7
.
Fit the thermostat by sliding the stem into the upper poc
k
et and carefully plugging the two male spade terminals on
the underside of the thermostat head into the corresponding female terminations on the element.
C
arefully push home
until the terminals are fully engaged.
8
.
Re-connect the electrical supply to the thermostat and earth post.
The
L
ive (Brown) conductor should be connected directly to the thermostat terminal mar
k
ed A.
The Neutral (Blue) conductor should be connected directly to the thermostat terminal mar
k
ed B.
The earth conductor should be connected to the threaded post on the brac
k
et mar
k
ed .
9.
Re-fit the protective cover over the immersion heater assembly and secure using the nut previously removed.
1
0.
Ensure the cylinder is correctly re-filled prior to switching on the immersion heater. Do not operate the immersion
heater with the protective cover removed.
S
POT W
EL
D
E
D
TO
I
M
E
R
SI
O
N
H
E
AT
E
R BO
SS
E
ARTH BRAC
KE
T
M5
NU
T
E
ARTH
L
AB
EL
E
ARTH
WAR
NIN
G
L
AB
EL
C
U
P
WA
S
H
E
R
P
L
A
IN
WA
S
H
E
R
S
HA
KE
PROOF
WA
S
H
E
R
M5 THR
E
AD
E
D
P
ILL
AR
Fig. 2
5
43
© Baxi Heating UK Ltd 2015