Unigas HTP2000 Installation Manual page 38

PART IV: MAINTENANCE
Replacing the spring in the gas valve group
To replace the spring in the gas valve group,proceed as follows:
1 Carefully twist the protection cap 1 and the O-ring 2.
2 remove the "set value" spring 3 from housing 4.
3 Replace spring 3.
4 Carefully insert the new "set value" spring. Pay attention to mount pro-
perly. First insert the spring part with smaller diameter in the housing.
5 Place O-ring 2 in protective cap 1. Screw in the protective cap with the O-
ring in it.
6 Stick the adhesive label for spring identification on the type plate.
Removing the combustion head
1 Remove the top H.
2 Remove the UV detector out of its housing: disconnect electrode cables and the light oil flexible hoses.
3 Loosen the screws V holding the gas manifold G, loosen the two connectors E and remove the assembly as shown.
Note: to replace the combustion head, reverse the operations described above.
4 Clean the combustion head by means of a vacuum cleaner; scrape off the scale by means of a metallic brush.
L
E
3 2 1
H
V
G
3
1
SKP Siemens actuator
Key
1 Inlet
2 Return
3 Gun opening
E Oil piping connections
H Cover
L Oil gun
38