Worcester GREENSTAR 25Si Instruction Manual page 48

INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR 25Si/30Si
8 716 115 165a (06/2008)
REPLACEMENT OF PARTS
11.1
A
The following components require
the air / gas manifold and fan
assembly to be removed:
Pressure switch
Fan
Electrode assembly
Burner
Heat exchanger
I M P ORTANT:
BETWEEN THE AIR/GAS MANIFOLD
11.2
AN D TH E H EAT E XCHANG E R I S
DISTURBED THE SEALING GASKET
B
MUST BE REPLACED.
IMPORTANT: AFTER REASSEMBLY
TH E C OM B USTION M UST B E
CH ECK E D US I NG TH E P RO CE-
DURE IN THE SECTION "SETTING
THE AIR/GAS RATIO". MEASURE-
MENT AND SETTING (IF NECES-
SARY) OF THE GAS RATIO MUST
11.3
NOT BE ATTEMPTED UNLESS THE
P E R SON I S EQU I P P E D W ITH A
C OM B USTION ANALYS E R C ON-
FORMING TO BS 7927 AND IS COM-
PETENT IN ITS USE.
11. Air / gas manifold and fan
assembly
Remove electrical connector from fan.
Remove wire clip from gas valve outlet then
pull gas adjustment assembly free from
plastic connector and pull clear of case
(see 6.1).
11.1 Undo and remove securing nut (A) from the
top of the heat exchanger.
11.2 *Remove retaining plate (B).
11.3 Rotate fan and air/gas manifold assembly
(shaded) around the top of the heat
exchanger until the lug on the air/gas
manifold is visible.
Lift up assembly and remove from boiler.
NOTE:
After re-assembly, check the CO/CO
levels as described in the setting of the
air/gas ratio section.
I F TH E JOI NT
2
REPLACEMENT OF PARTS
47