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12 Maintenance (continued)
Cleaning heat exchanger
1. Shut down water heater:
• Follow the “To Turn Off Gas to Appliance” instructions
for the water heater on pages 45 and 46.
• Do not drain the water heater unless it will be exposed
to freezing temperatures.
2. Allow time for the water heater to cool to room temperature
if it has been firing.
3. Remove the blower assembly (gas air/arm) from the heat
exchanger access cover. Set bolts aside.
4. Remove the nuts securing the heat exchanger access cover to
the heat exchanger and set aside.
5. Remove the heat exchanger access cover, cover gasket(s) and
chamber insulation assembly.
The water heater contains ceramic fiber
materials. Use care when handling these
materials per instructions listed on this page.
Failure to comply could result in severe
personal injury.
6. Use a vacuum cleaner to remove any accumulation on the
water heater heating surfaces. Do not use any solvent.
7. Finish cleaning using a clean cloth dampened with warm
water.
8. Install access cover gasket, chamber insulation assembly and
cover.
9. Secure nuts on the studs. DO NOT overtighten.
10. Re-install the blower assembly (gas air/arm) using the bolts
set aside in Step 3.
11. Close isolation valves on piping to isolate water heater from
system. Attach a hose to the water heater drain and flush
water heater thoroughly with clean water by using purging
valves to allow water to flow through the water make-up line
to the water heater.
12. When the water heater has been flushed, restore water
heater to operation.
13. Perform start-up and check-out procedures listed in Section
10 - Start-up.
Oiled bearing circulators
1. The circulator shipped with the Shield water heater is water-
lubricated. No oiling is required.
2. Check other circulators in the system. Oil any circulators
requiring oil, following circulator manufacturer’s
instructions. Over-oiling will damage the circulator.
ƽ WARNING
Handling ceramic fiber materials
REMOVAL OF COMBUSTION CHAMBER
LINING
The combustion chamber door
insulation in this product contains
ceramic fiber material. Ceramic fibers
can be converted to cristobalite in very
high temperature applications. The
International Agency for Research on
Cancer (IARC) has concluded,
“Crystalline silica inhaled in the form of
quartz or cristobalite from occupational
sources is carcinogenic to humans
(Group 1).”:
Avoid breathing dust and contact
with skin and eyes.
• Use NIOSH certified dust respirator
(N95). This type of respirator is based
on the OSHA requirements for
cristobalite at the time this document
was written. Other types of respirators
may be needed depending on the job site
conditions. Current NIOSH
recommendations can be found on the
NIOSH website at
http://www.cdc.gov/niosh/homepage.ht
ml. NIOSH approved respirators,
manufacturers, and phone numbers are
also listed on this website.
• Wear long-sleeved, loose fitting
clothing, gloves, and eye protection.
Apply enough water to the
combustion chamber lining to prevent
airborne dust.
Remove the combustion chamber
lining from the water heater and place it
in a plastic bag for disposal.
Wash potentially contaminated
clothes separately from other clothing.
Rinse clothes washer thoroughly.
NIOSH stated First Aid.
Eye: Irrigate immediately.
Breathing: Fresh air.
ƽ WARNING
Installation & Service Manual
TM