Download Worcester 28i Junior Specifications

2.11.2 Domestic Hot Water:
The appliance can provide domestic hot water whenever it is
switched on electrically.
A demand for hot water will light the burner. The pressure will
immediately rise to maximum. At the end of the demand the fan
will continue to run for 35 seconds if there is no heating
demand.
In winter it may be necessary to reduce the flow at the taps to
maintain the delivery temperature.
Yes
Replace multiway
connector to position
ST16 (but not fan
connector at ST1) and
reset/restart the
boiler.
Is there mains 230V
across the right (L)
and left (N) tracks at
board position ST1?
NOTE: Take care not to
short L to N.
2.11.3 Domestic Hot Water and Central Heating:
The demand for hot water will override the central heating
function when the appliance is in the heating and hot water
mode of operation.
No
Replace control board.
In the unlikely event
of this not solving the
problem replace code
plug.
Yes
Replace fan connector
ST1.
Remove electrical
connectors from air
pressure switch and
reset/restart boiler.
Is there continuity
between C and NO
terminals (where wires
were fitted) when the
fan runs?
(Test within 30
seconds).
Fig. 2. Water flow diagram.
10
8
No
Pressure switch has
not closed. Are the
silicon tubes in good
condition and free of
condensation.
No
Replace tubes. If
condensation has
occurred, also replace
pressure switch and
check condition of
Venturi in the fan.
Yes
Inspect the flue. Is it
free of any
restrictions?
No
Rectify flue problem.
Yes
9
Replace air pressure
switch.
Note: In the unlikely
event of this not
solving the problem
inspect the pressure
pick-up (Venturi) in the
fan or fan may not be
running freely.
Yes
6
Does the burner ignite
(burner light on) and
run for a short priod
before the fault
occurs?
11
No
Remove multiway
connector from board
position ST16.
Is there continuity of
the green cables to
the air pressure
switch?
No
Yes
7
Yes
Replace control board.
Pressure switch has
opened during
operation.
Check flue for
blockage.
Also investigate sense
tubes and pressure
switch.
12
1.
2.
3.
4.
5.
6.
7.
2
5
CH flow
Domestic hot water flow
Mains cold water inlet
CH return
Pressure relief valve discharge
Domestic water flow turbine
Circulating pump
3
8. Expansion vessel
9. Primary heat exchanger
10. Expansion vessel charge point
11. Relief valve
12. Boiler drain point
13. Charging link (optional extra)
4
4
13
TEST F
1
The gas valve mode
switch (concealed by
the facia side panel)
is not set correctly
Turn to 'NORM'
position
41
Repair cables or
replace main harness.