andrews L24/31, Installation Manual, Operation And Service Manual

Page: 39 / 61

SERVICING SECTION 6
Servicing must be carried out by a properly qualified person
Whilst giving these instructions for the care of the Heater, it is recommended that checks
are carried out by the installer or local gas authority, at least annually. Ensure good
ventilation by keeping the heater free of extraneous materials and clear of dust and lint.
Keep pipework, flue and tops of heaters clear of any combustible materials. A water
softener or lime inhibitor should be employed in hard water areas. The heater should be
inspected every few months via the hand hole cleanout and lime or silt deposits removed.
Failure to do so will shorten heater life and may invalidate the warranty.
NOTE! The cleanout hole gasket must be renewed whenever the cover is removed.
Before servicing, carry out the following operations.
1) Turn off the gas service cock.
2) Turn off the cold water supply to the heater.
3) Turn on the hot water draw-off taps served by the water heater, or, for multiple
installations, turn off the hot water outlet connection valve and secondary return valve.
4) Drain down using the drain valve on the heater.
The burner assembly should be checked and cleaned annually.
1. Depress catch under the gas control knob and turn to OFF. Remove outer burner cover
and slide inner door to right. On L63/71 and L84/74 models, the inner cover must be
lifted out.
2. Disconnect pilot tube, thermocouple and main burner supply tube from bottom of control
valve. Withdraw burner assembly from heater.
3. Remove screw securing pilot assembly to main burner supply tube.
4. Remove gland nut securing pilot tube to pilot assembly. Withdraw pilot tube and remove
pilot restrictor. Clean pilot restrictor with acetone and blow through pilot burner with
compressed air.
5. Remove main burner pipe locknut and remove the pipe. Remove main jet and clean with
acetone. Blow through main burner with compressed air. CLEAN ORIFICES WITH
WOOD SPLINTER. DO NOT USE SHARP METALLIC OBJECTS.
6. Re-assemble in reverse order of steps 2 - 5, but note: DO NOT OVERTIGHTEN THE
THERMOCOUPLE CONNECTION. SCREW IN FINGER TIGHT THEN TIGHTEN A
FURTHER 1/4 TURN USING A SPANNER.
7. Turn gas control knob to PILOT and depress. Using leak detection fluid, check joints at
both ends of the pilot supply tube. Seal if necessary. DO NOT EXAMINE WITH A
NAKED FLAME.
8. Allow 3 minutes for unburned gas to disperse. Light the pilot and check flame is correct.
(see Section 4, Commissioning). Slide inner door to left (replace on Models L63/71 and
L84/74) and turn gas control knob to ON. The main burner will light.
9. Check main burner connection tube at control valve with leak detection fluid and seal if
necessary. Replace outer cover.
INTRODUCTION
BURNER
ASSEMBLY
STANDARD
RANGE
PRE-SERVICE
OPERATIONS
34