John Wood Commercial - 300-400K BTU - Manual (Page 60)

60
maintenance schedule
table 13
component operation interVal reQuired
Tank
Sediment
removal
Semi Annually
Flushing
Tank
Lime Scale
removal
Semi Annually uN-LIME®
Anode rods Inspection
Cleaning
Annually
Clean Scale
Deposits
T&P Valve Test operation
Semi Annually
Test
Vent System Inspection
Annually
Termination
Screens Clean
Reseal/Repair
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 Features And Components on page 7 for
the location of the water heater components described below.
Burn harzard.
Hot water discharge.
Keep hands clear of drain
valve discharge.
to drain the water heater storage tank:
1. Turn off the electrical supply to the water heater.
2. Turn off the gas supply at the Main gas Shutoff Valve if
the water heater is going to be shut down for an extended
period.
3. Ensure the cold water inlet valve is open.
4. Open a nearby hot water faucet and let the water run until the
water is no longer hot.
5. Connect a hose to the water heater drain valve and terminate
it to an adequate drain.
6. Close the cold water inlet valve.
7. Open the water heater drain valve and allow all the water to
drain from the storage tank.
8. Close the water heater drain valve when all water in the
storage tank has drained.
9. Close the hot water faucet opened in Step 4.
10. If the water heater is going to be shut down for an extended
period, the drain valve should be left open.
maintenance
general
keep water heater area clear and free from combustible
materials, gasoline and other flammable vapors and liquids. See
Locating The Water Heater on page 11.
Water heater maintenance includes periodic tank flushing and
cleaning, and removal of lime scale. The water heater should
be inspected and adjusted to maintain proper combustion.
See Initial Start up on page 49. A periodic inspection of the
venting system should be made. Where used, water circulating
pump(s) should be oiled according to the pump manufacturer's
recommendations.
precautions
Do not operate the water heater if it has
been exposed to or exhibits the following:
Flooding at or above the level of the burner or controls.
•
External damage. •
Firing without water.
•
Sooting.
•
Do not operate the water heater until all corrective steps
have been made by a qualified service agent.
CAUTION
Never operate the water heater without first being certain it is
filled with water and a properly sized and rated Temperature-
Pressure relief Valve is installed in the relief valve opening on
the water heater. See Temperature-Pressure relief Valve on
page 15.
Explosion Hazard
Overheated water can cause
water tank explosion.
Properly sized temperature and
pressure relief valve must be
installed in the opening provided.
Should overheating occur or the gas supply fail to shut off, turn
of the Main gas Shutoff valve. See Figure 52 on page 36.
Water heater maintenance includes periodic tank flushing and
cleaning, and removal of lime scale. The water heater should
be inspected and adjusted to maintain proper combustion.
refer to the following table. A periodic inspection of the venting
system should be made. Where used, the water circulating
pump should be oiled according to the pump manufacturer's
recommendations.