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Maintenance and service
5.3 Pilot
Inspecting pilot
The pilot should burn with a clean sharp blue flame. The
flame should fully engulf the tip of the thermocouple. If
it does not, clean the pilot assembly using the
procedure below.
Cleaning pilot assembly
•1. Shut off gas to heater using installer supplied
manual gas shutoff, then remove front cover.
•2. Carefully loosen 8 mm pilot tube nut shown below.
Once loosened with wrench, continue by hand. Do
not pull pilot tube down. Follow next step.
•3. Remove both pilot bracket screws that mount to
front of burners.
Fig. 24 Pilot assembly
•4. Lift up pilot bracket slowly (8 mm nut may need to
be loosened further)
•5. The pilot orifice sits on top of the pilot tube.
Stamped on it will be a number identifying the gas
type. [5 - Natural Gas] [49 - LP].
•6. We recommend that you replace if dirty or clogged
(especially LP). If cleaning, compressed air or
aerosol sprayed carburetor cleaner will work. Soak in
cleaner if necessary..
•7. Blow through pilot burner that is affixed to the pilot
bracket. If air screen on right side of pilot bracket is
dirty or clogged, remove and clean.
•8. Place new or cleaned pilot orifice back on top of
pilot tube.
•9. Set pilot bracket on top of the pilot tube.
•10. Begin to hand thread the 8 mm nut to the pilot
bracket being sure not to cross thread. Once started
tighten pilot bracket to front of burners with both
screws.
•11. Carefully tighten 8 mm nut with wrench.
•12. Turn on gas and check for a leak at the 8 mm nut
connection by applying soap solution, then pushing
in pilot button. Bubbles are a sign of a leak.
•13. If no leaks are found replace front cover and
return heater to service.
5.4 Main burners
The main burner flames should be blue, with a more
intense blue cone in the center core. Yellow flames
could be a sign of wrong size gas orifices, dirty burners
or a blockage on the heat exchangers fins. If some
burners have yellow flames while others have blue
flames, it is likely that dust, lint or spider webs have
partially clogged the burner venturis. To clean the
burners, contact a gas service person.
5.5 Vent assembly
Inspect the draft hood and heat exchanger fins for signs
of soot build-up or any other foreign material such as
spider webs. Clean out any debris found in the vent
hood. Signs of soot indicate insufficient combustion air
or exhaust draft. Check for vent assembly blockage or
combustion air blockage on the underside of the unit.
5.6 Mineral scale build-up
The GWH 1600 PS, when operated at lower
temperatures settings, does not accumulate mineral
build-up. If however, the heater is used at the higher
temperature settings and the water has a high mineral
content, periodic descaling may be necessary. The heat
exchanger should be flushed with a descaling solution.
5.6.1 Descaling heat exchanger
1. Shut off the water supply to the water heater using
(installer supplied) shutoff valves.
2. Open hot water taps to drain and relieve pressure
from the plumbing system
3. Drain water from the unit's heat exchanger by
disconnecting inlet and outlet water connections
4. Connect the line (A) from the outlet of the circulating
pump (installer supplied) to the inlet water fitting on the
water heater
5. Using another line (B), connect to the water outlet
fitting on the water heater. Route the other end of this
line into a descaling reservoir
Caution: Pilot orifice may fall out when
pilot tube and pilot bracket are
separated.
Caution: Do not ream or poke orifice as
it will enlarge orifice opening.
bracket screw
orifice
8mm nut
pilot filter
thermocouple
Piezo electrode