Unigas G258A Manual Of Installation - Use - Maintenance page 42

PART IV: MAINTENANCE
Removing the combustion head
Remove the cover C.

Remove the electrodes cables;

Unscrew the 3 screws V which hold in position the gas manifold G.

Some models are provided with the T baffle. Move the gas manifold ahead and remove the baffle.

Pull out the complete group as shown in the picture below.

Clean the combustion head by a compressed air blow or, in case of scale, scrape it off by a scratchbrush.

Note: to replace the combustion head reverse the procedure described above having care to place correctly the O ring (OR) between
burner and gas manifold.
AR V
VRT
OR
C
T
Electrodes Adjustment
Adjust the electrodes position, according to the quotes shown othe next picture
ATTENTION: avoid the ignition and detection electrodes to contact metallic parts (blast tube, head, etc.), otherwise the
boiler's operation would be compromised. Check the electrodes position after any intervention on the combustion head.
G
C
7
Key
VRT Head adjusting screw
AR Threaded rod
V Fixing screw
G Gas manifold
OR "O" ring
C Cover
T Baffle
AR
A = 4
B = 8
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G