Component Access; Checking Heat Exchanger Assembly - Worcester Greenstar 4000 Installation And Maintenance Instructions Manual

Inspection and maintenance
Maintenance reminder options
Accessing the maintenance reminder options.
▶ Service menu > Settings > Special function > Maintenance.
Options available.
• Without (off)
– No reminder.
• Burner run time
– Service reminder based on the number of hours the burner has
been active, (1000 hours up to 6000 hours, default 6000 hours).
• Boiler run time
– Service reminder based on the number of months the boiler has
been operating, (1 month up to 72 months (6 years), default 12
months).
• Service date (Only available with installed Key Timer (accessory))
– Service reminder where a specific calendar date can be selected.
• Landlord function (only available with installed Key Timer
(accessory).
– Operates in the same way as service date with the additional
option of reducing CH and DHW comfort.
Maximum system pressure
▶ 2.5 bar must not be exceeded when the heating system water is at
maximum temperature. If this pressure is exceeded then an
additional expansion vessel must be fitted into the system return as
close as possible to the appliance.
▶ If the system does not retain the pressure, the pressure relief valve
(PRV) and the heating system should be checked for leaks.
8.2

Component access

Removing the front casing
The front casing is secured with two screws which are critical to maintain
the case seal and to prevent unauthorised removal (electrical safety).
▶ Always secure the casing with these screws.
▶ Loosen the two screws [1] and pull the bottom of the casing forward.
▶ Lift off the casing.
Fig. 69 Removing the front casing
58
8.3
▶ Remove the front casing.
▶ Remove the cap from the test nipple, and connect a pressure gauge.
Fig. 70 Test nipple at the mixing device
NOTICE
Fan pressure test
▶ The appliance must be running at maximum output in chimney sweep
This test is to determine if the heat exchanger requires cleaning or
additional actions.
Fan pressure test reading.
▶ The pressure reading will be in negative values.
Appliance fan pressure test values
Natural Gas appliances
Table 28 Natural Gas values
LPG appliances
Table 29 LPG values
1
If the manometer reading is within tolerance, in the white area of the
table values.
▶ The heat exchanger/exhaust path/siphon does not require attention.
If the manometer reading is out of tolerance, in the shaded area of the
table values then carry out the following checks.
▶ Check that the siphon is not restricted or blocked.
▶ Check the exhaust paths for restrictions.
▶ Clean the heat exchanger with a suitable cleaning tool, refer to

Checking heat exchanger assembly

mode for the fan pressure test, ( Setting the appliance to
maximum).
Appliance Cleaning required
output
 -5.1 mbar -5.2 mbar  -12 mbar
30kW 0 mbar
 -3.8 mbar -3.9 mbar  -12 mbar
25kW 0 mbar
Appliance Cleaning required
output
 -6.2 mbar -6.3 mbar  -12 mbar
30kW 0 mbar
 -4.5 mbar -4.6 mbar  -12 mbar
25kW 0 mbar
cleaning section.
Greenstar 4000 – 6 720 891 161 (2020/09)
No cleaning required
Value
No cleaning required
Value