Safety Valve; Lower Automatic Air Release Valves; Water Pressure Switch; Primary Thermistor - Benchmark Procombi A Series Installation & Servicing Instructions Manual

6.6 SAFETY VALVE (fig. 19)
Carry out component removal procedure as de-
scribed in 6.4. Disconnect the outlet pipe (A) from
the safety valve, remove safety valve locking pin
(B) from the hydraulic manifold. Replace in the
reverse order.
B
A
fig. 19
6.7 LOWER AUTOMATIC AIR RELEASE VALVE (fig.
18)
Carry out component removal procedure as de-
scribed in 6.4. Remove the expansion pipe locking
pin (D) from the pump assembly and remove the
expansion pipe. Locate and remove the AAV
locking pin (G) from the pump assembly and
remove the AAV assembly (H). Replace in the
reverse order.
6.7.1 TOP AUTOMATIC AIR RELEASE VALVE (fig.
20)
Carry out component removal procedure as de-
scribed in 6.4. Remove the drain pipe. Unscrew
the top AAV. Replace in the reverse order. Loctite
or similar should be used as a thread sealant for
the AAV.
6.8 WATER PRESSURE SWITCH (fig. 19)
Carry out component removal procedure as de-
scribed in 6.4. Locate and remove the locking pin
(C) from the water pressure switch. Remove the
wiring. Carefully withdraw the switch. Replace in
the reverse order.
6.9 PRIMARY THERMISTOR (fig. 1)
Carry out component removal procedure as de-
scribed in 6.4. Unclip and remove the air chamber
front cover. Unclip the primary thermistor from the
flow outlet pipe. Disconnect thermistor electrical
plug. Replace in the reverse order.
6.10 RETURN THERMISTOR (fig. 1)
Carry out component removal procedure as de-
scribed in 6.4. Unclip and remove the air chamber
front cover. Unclip the return thermistor from the
return inlet pipe. Disconnect thermistor electrical
plug. Replace in the reverse order.
6.11
C
Fig. 21
6.12
B
A
Fig. 20
fig. 22
6.12.1 INJECTOR (fig. 22)
PRINTED CIRCUIT BOARD (fig. 21)
Carry out component removal procedure as de-
scribed in 6.4. Pull the control fascia forward and
lower it. Push the clips (A) which secure the PCB
cover, remove cover, after carefully taking note
of all wiring connections and jumper tag configu-
ration. Unhook and remove connection block (B).
Disconnect all wiring from the PCB, locate and
remove the PCB securing screws, remove the
required PCB. Replace in the reverse order en-
suring that the position of the 3 control knobs are
correctly aligned with
potentiometers on the PCB.
Ensure that the correct jumper tag configuration
has been respected. It will be necessary to check
the functioning of the PCB is set for the correct
boiler type/application.
GAS VALVE (fig. 22)
Carry out component removal procedure as de-
scribed in 6.4. The gas valve must be changed as
complete unit. Disconnect the electrical plug and
leads from the gas valve, slacken and unscrew
gas valve inlet and outlet connections. Please
note, the sealing washers (B) must be discarded
and replaced with new sealing washers. Discon-
nect the compensation pipe (C). Locate and re-
move gas valve retaining screws (D) on the un-
derside of the boiler if required, the gas valve can
now be removed. Replace in the reverse order.
Check and adjust burner pressure settings.
WARNING, A GAS SOUNDNESS CHECK MUST
BE CARRIED OUT.
D
Carry out component removal procedure as de-
scribed in 6.4. Unscrew and remove gas pipe
connections (A&E). Locate and remove the injector
(F) inside the pipe. Replace in the reverse order.
Check and adjust burner pressure settings.
WARNING, A GAS SOUNDNESS CHECK MUST
BE CARRIED OUT.
the respective
B
A
F
A
E
B
B
C
15