John Wood Commercial - AJWSC - Manual (Page 25)

8. Replace and sufficiently tighten the two screws holding
the Pilot/Burner Assembly in place.
9. Reconnect the gas supply line to the gas valve.
10. Turn on gas at main shutoff valve.
11. Check for gas leaks and proper operation on the unit
after servicing.
Gas Valve Removal and Replacement
It is recommended that this maintenance be performed by a
qualified service technician.
1. Turn the integrated control to its lowest setting.
2. Turn off gas at manual gas shut-off valve (see Figure 3
for reference) and disconnect electrical power from
water heater.
3. Unplug the 4 wires located on the gas valve. Label wire
position for correct reattachment.
4. Disconnect pilot tube from the gas valve.
5. Disconnect the main gas line from the gas valve. Use
care not to crack the gas valve housing.
6. Carefully unscrew the gas valve from the burner assem-
bly.
Important: When removing gas valve do not use a pipe
wrench or vise to grip the body.
7. When replacing the gas valve, use an approved Teflon®
or pipe joint compound on the pipe threads.
8. Screw the new gas valve onto the burner assembly.
9. Reconnect the pilot tube to the gas valve.
10. Reconnect the main gas line to the gas valve.
11. Turn the gas supply on and check for leaks. Use a chlo-
rine-free soap and water solution (bubbles forming indi-
cate a leak) or other approved method.
12. Reconnect the 4 wires to their proper location and
restore electrical power to the unit.
13. Verify proper operation after servicing this water heater.
14. If additional information is required, contact the Product
Service and Support Group at 1-888-479-8324.
Anode Rod Inspection
Each water heater contains at least one anode rod, which
will slowly deplete while protecting the glass-lined tank from
corrosion and prolonging the life of the water heater. Certain
water conditions will cause a reaction between the rods and
the water. Once the anodes are depleted, the tank will start
to corrode, eventually developing a leak. The most common
complaint associated with the anode rod is a "rotten egg
smell" produced from the presence of hydrogen sulfide gas
dissolved in the water. Do not remove this rod permanently
as it will void any warranties, stated or implied. A special
anode is available for this complaint. This rod may reduce
but not eliminate water odour problems. The water supply
system may require special filtration equipment from a
water conditioning company to successfully eliminate all
water odour problems. Artificially softened water is exceed-
ingly corrosive because the process substitutes sodium ions
for magnesium and calcium ions. The use of a water sof-
tener may decrease the life of the water heater tank. The
anode rods should be removed from the water heater tank
every 3 years for inspection. If the rods are more than 50%
depleted, the anode rods should be replaced.
To replace the anodes:
1. Turn off gas supply and electrical power to the water
heater.
2. Shut off the water supply and open a nearby hot water
faucet to depressurize the water tank.
3. Drain approximately 20l (5 gal) of water from tank
(Refer to “Draining and Flushing” for proper proce-
dures). Close drain valve.
4. Remove old anode rods.
5. Use Teflon® tape or approved pipe sealant on threads
and install new anode rods.
6. Turn on water supply and open nearby hot water faucet
to purge air from water system.
7. Restart the water heater as directed under “Lighting &
Operating Instructions”. See the "Parts Reference
Illustration" for anode rod location.
Replacement Parts
Replacement parts may be ordered through your plumber or
the local distributor. When ordering replacement parts,
always have the following information ready:
1. model, serial and product number
2. type of gas
3. item number
4. parts description
See “Parts Reference Illustration” for a list of available
repair parts.
Space Heating
If this unit is to be used to supply both space heating and
domestic potable (drinking) water then the following instruc-
tions must be followed:
1. All piping and components used must be suitable for
use with domestic (potable) drinking water.
2. Do not use piping or components that have been con-
nected to a non-potable system or treated with chro-
mates or other toxic chemicals. Do not add any chemi-
cals to the water heater piping.
3. If system requires temperatures in excess of 49°C
(120°F) install a tempering valve, per the manufactur-
er’s instructions, in the domestic (potable) hot water line
to limit the risk of scalding (See Figure 8).
4. Be sure to follow the manual(s) shipped with the heat-
ing system. Also follow any provincial, state or local
codes.
Figure 24 Pilot/Burner Assembly Removal
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VIII) COMBO HEATING