Fan Pressure Test - Worcester GREENSTAR 24i Junior Installation Instructions Manual

6.4

FAN PRESSURE TEST

This test is to determine if the heat cell
requires cleaning/attention.
SETTING THE BOILER TO MAXIMUM
1. Press and HOLD service button for more than 10
seconds
2. Set the Central Heating temperature to maximum.
– The service button will illuminate continually and
the blue power indicator will pulse 5 times.
– The boiler will stay in this mode for 15 minutes
unless the service button is pressed again.
1.
2.
Fig. 71 Set boiler to maximum
When running in the service mode, the
boiler will operate both the Central Heating
and DHW circuits. This is to allow sufficient
time for setting procedure.
It will be necessary to run water through the
DHW circuit to ensure that the boiler will not
cycle on low heating demands.
FAN PRESSURE
Fig. 72 Fan pressure test point
6 720 644 741a (2010/10)
B Remove the cover and connect a digital manometer to
the fan pressure test point.
B After measurement replace test point cover.
B The pressure will read negative, refer to the chart in
figure 73.
NOTICE:
The boiler must be run at maximum output
for Fan Pressure test and the Flue Gas
analysis.
FAN PRESSURE TEST
Clean Heat Ex.
NG Boilers
28 i Junior:
- 3.1
24 i Junior:
0 1 2
LPG Boilers
28 i Junior:
24 i Junior:
0 1 2
Fig. 73 Fan pressure readings
If the boiler fails the fan pressure test then before
adjusting the air/gas ratio, try the following:
B Check the syphon is not blocked.
1. Remove the screws securing the sump cover.
2. Remove the sump cover.
3. Clean the sump and heat exchanger with a suitable
brush
B Check the exhaust path and flue for restriction.
B Re-check the Fan Pressure readings
Fig. 74 Sump access
SERVICE AND SPARES
Heat Ex. ok
- 3.9
3 4 5 6 7 8
mbar
- 4.6
- 3.6
3 4 5 6
7 8
mbar
6720644741-07.1Wo
3.
2.
1.
1.
6720643895-112.1Wo
45