VOKERA Hydra Installation & Servicing Instructions Manual - page 22
20
6.9
NTC THERMISTORS (temperature sensors)
Carry out component removal procedure as de-
scribed in section 6.4.
Cold water inlet sensor (fig. 20)
Disconnet thermistor electrical plug. Using a 13
mm spanner slacken and remove the thermistor
and sealing washer.
Replace in the reverse order.
Flow & return sensors (fig. 1 & 21)
Pull back protective boot and remove the 2 spade
connectors. Slacken and remove the 2 securing
screws.
Replace in the reverse order.
6.10
PRINTED CIRCUIT BOARD (PCB) (fig. 22)
Carry out component removal procedure as de-
scribed in section 6.4.
●
Locate and remove the 2 screws that secure
the PCB housing bracket to the underside of
the air chamber.
●
Remove the 4 screws that secure the housing
cover to the housing.
●
After carefully taking note of all wiring
connections, disconnect all wiring from the
PCB.
●
Locate and remove the 3 screws that secure
the PCB to the housing.
Replace in the reverse order.
6.11
GAS VALVE (fig. 23)
Carry out component removal procedure as
described in section 6.4.
The gas valve must be changed as complete unit.
Unclip and remove the air chamber cover.
Disconnect the electrical plug from the gas valve.
Disconnect silicone tube from gas valve regulator.
Slacken and unscrew gas valve inlet and outlet
connections. Please note, the sealing washers
must be discarded and replaced with new sealing
washers. The gas valve can now be removed.
Replace in the reverse order. Refer to section
seven for detailed instructions on how to set-up
the gas valve. WARNING, A GAS SOUNDNESS
CHECK MUST BE CARRIED OUT.
6.12
FAN (fig. 23A)
Carry out component removal procedure as
described in section 6.4.
Unclip and remove the air chamber cover.
Disconnect the electrical plug from the fan. Locate
and remove the 4 bolts that secure the fan to the
pre-mix manifold. Replace in the reverse order.
6.13
BURNER (fig. 24 & 26)
Carry out component removal procedure as de-
scribed in section 6.4.
Unclip and remove the air chamber cover. Locate
and remove the 8 nuts (10 mm) securing the pre-
mix manifold/burner assembly.Disconnect the
gas valve outlet pipe at its connection to the pre-
mix manifold. Disconnect the silicone pipe from
the pre-mix manifold. Gently pull away the fan/
pre-mix manifold assembly from the heat
exchanger. Remove the earth wire from the burner
earth tab and gently lift the burner from its location.
Replace in the reverse order. Please note, ensure
all seals are in good condition, taking care to
ensure they are replaced correctly.
Fig. 20
Fig. 22
Fig. 21
Screw
Screw
Fig. 23
Fig. 23A
Actuator
A c t u a t o r
locking pin
Cold water inlet sensor