John Wood Electric Water Heaters - Manual (Page 7)

cian. In systems where the relief valve discharges periodi-
cally, this may be due to thermal expansion causing pres-
sure build up. See “Pressure Build-Up (Thermal
Expansion)” section.
Element Replacement
1. See “Draining the Tank” section to remove water from the
heater.
2. Turn the electrical supply to the water heater "OFF".
3. Remove the access door(s) and insulation pad(s).
4. Disconnect wires from heating element terminals.
5. Unscrew the element using a 1-1/2 in. socket wrench or
tool number S1008, available from your water heater dis-
tributor.
6. Replace element with new one, taking care that sealing
gasket is in the groove of element flange.
7. Re-connect wiring, and replace Di-Electric shields.
8. Ensure insulation pad is in the door cavity. Replace
access door(s).
9. Fill tank with water BEFORE turning ELECTRICITY on.
See “Filling the Tank” section.
Thermostat Replacement
1. Turn the electrical supply to the water heater "OFF".
2. Remove the access door(s) and insulation pad(s).
3. Disconnect wires from thermostat(s).
4. Lift prongs off bracket and slide thermostat up and out.
5. Replace in reverse order, taking care that thermostat(s)
is flush against the tank.
6. Ensure insulation pad is in the door cavity. Replace
access door(s).
7. Turn the electrical supply to the water heater "ON".
Cathodic Protection: Anode
Maintenance
Your water heater has been supplied with an anode rod that
protects the tank from corrosion. As the rod works, it slowly
dissolves over time and must be replaced. If the anode is
less than 10mm (3/8 in.) diameter, or any exposed bare
core, replace. Depending on water conditions, an anode
can last from one to ten years. Many localities treat their
water, which can have significant effect on the life of your
heater. Water conditioning such as over softening can
accelerate the rate at which the anode rod is consumed.
Rapid depletion can leave a heater unprotected causing a
premature failure. As with any water heater, it is good prac-
tice to check the anode annually to see if it needs replacing.
Anode Inspection/Change
1. Turn "OFF" the electrical supply to the tank.
2. Close the cold water supply valve.
3. Open a nearby hot water faucet served by the system
to depressurize the system.
4. Connect a hose to the drain valve and drain enough
water to empty the piping system as directed in the
“Draining the Tank” section.
5. Using a 1-1/16 in. socket, remove the anode and inspect
it. The surface may be rough, full of pits and crevices, but
this is normal. If it is less than approximately 6mm (1/4
in.) in diameter, or the inner steel core is exposed, the
anode should be replaced.
6. Apply Teflon TM tape or sealing compounds approved for
use with potable water, to the threads of the anode and
install into the tank top.
7. Open the cold water supply valve and open a nearby hot
water faucet to purge air from the tank as directed in the
“Filling the Tank” section.
8. Check for leaks, repair as required, and re-test.
9. Turn "ON" the electrical supply to the tank.
Operating a water heater without an actively working
anode rod will void any warranties, stated or implied.
Tank Clean-Out
1. A clean-out opening is provided on certain models for
periodic cleaning of the tank. Power supply must be shut
off and the heater drained before opening the clean-out.
2. To clean heater through the clean-out opening, proceed
as follows:
a) Remove outer door from side of the casing.
b) Mark the insulation at the 12 o’clock position. Using
the opening in the outer casing as a guide cut out the
insulation covering the clean-out flange.
c) Remove the six (6) hex head screws securing the
tank clean-out plate and remove the plate.
d) Remove lime, scale or sediment using care not to
damage the glass lining of the tank.
– 7 –
CAUTION
The out-flowing water is hot. Avoid splash-
ing the water on yourself or on the sur-
roundings where it may cause damage.
Figure 3 T&P Relief Valve Test
TEMPERATURE AND
PRESSURE RELIEF VALVE
MANUAL RELIEF VALVE
DISCHARGE LINE TO DRAIN
WARNING
Electrical Shock Hazard
Disconnect power before
servicing. Replace all parts
and panels before operating.
Failure to do so can result in
death or electrical shock.