John Wood Envirosense Power Direct Vent (May 2010 or later) - Manuel (Page 48)

48
POWERED ANODE ROD (OPTIONAL MODELS)
To insure a long, trouble-free operating life, certain models of
water heaters covered in this manual are factory equipped with
a powered anode system. The anode rod is of a permanent
design and does not need replacing unless damaged.
Inspection and cleaning should be performed once a year.
NOTE: Follow the instructions to drain the water heater storage
tank first. Remove the powered anodes from the water heater by
loosening the 3/4” NPT bushing that forms the top of the anode
rods. Do not disassemble the retaining nut and wire terminal
from the top while installed in the water heater, the anode rods
electrode may fall inside the tank. Remove the entire anode rod
from the water heater prior to inspection. Clean the anode rods
with a soft cloth and reinstall. Follow the instructions for filling
the water heater when finished.
TEMPERATURE-PRESSURE RELIEF VALVE TEST
It is recommended that the Temperature-Pressure Relief Valve
should be checked to ensure that it is in operating condition every
6 months.
When checking the Temperature-Pressure Relief Valve operation,
make sure that (1) no one is in front of or around the outlet of the
Temperature-Pressure Relief Valve discharge line, and (2) that the
water discharge will not cause any property damage, as the water may
be extremely hot. Use care when operating valve as the valve may be
hot.
To check the temperature-pressure relief valve, lift the lever at the end of
the valve several times, see Figure 37. The valve should seat properly
and operate freely.
If after manually operating the valve, it fails to completely reset
and continues to release water, immediately close the cold
water inlet to the water heater and drain the water heater, see
Draining And Flushing on Page 48. Replace the Temperature-
Pressure Relief Valve with a properly rated/sized new one, see
Temperature-Pressure Relief Valve on Page 21 for instructions
on replacement.
DISCHARGE PIPE
TEMPERATURE-PRESSURE
RELIEF VALVE
Figure: 37
If the Temperature-Pressure Relief Valve on the water heater
weeps or discharges periodically, this may be due to thermal
expansion.
NOTE: Excessive water pressure is the most common cause of
Temperature-Pressure Relief Valve leakage. Excessive water
system pressure is most often caused by “thermal expansion”
in a “closed system.” See Closed Water Systems and Thermal
Expansion on Page 21. The Temperature-Pressure Relief Valve
is not intended for the constant relief of thermal expansion.
Temperature-Pressure Relief Valve leakage due to pressure
build up in a closed system that does not have a thermal
expansion tank installed is not covered under the limited
warranty. Thermal expansion tanks must be installed on all
closed water systems.
DO NOT PLUG THE TEMPERATURE-PRESSURE RELIEF
VALVE OPENING. THIS CAN CAUSE PROPERTY DAMAGE,
SERIOUS INJURY OR DEATH.
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
DRAINING AND FLUSHING
It is recommended that the water heater storage tank be drained
and flushed every 6 months to reduce sediment buildup. The
water heater should be drained if being shut down during freezing
temperatures. See “Figure 1B: 50 GALLON UNIT” & “Figure 1C: 75
GALLON UNIT” Features And Components in this manual for the
location of the water heater components described below.
Burn harzard.
Hot water discharge.
Keep hands clear of drain
valve discharge.
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.