PVI Industries PVI Water Heaters Manuals: Essential Guide for Maintenance and Safety Inspections

MAINTENANCE AND SAFETY INSPECTIONS

To Minimize Scale Accumulation in Tank Periodic Inspection of Operational Components

1.A preventative maintenance program should be established to assure a long, trouble-free life of the water heater.

2.The tank should be flushed at two or three month intervals depending on water conditions in your location. To flush, turn off the electrical disconnect switch to prevent the burner from operating. Open the drain valve and allow water to flow through the tank until it runs clear. Close the drain valve and turn the electrical switch back on. Draining two or three gallons from the bottom of the tank on a weekly basis will also help prevent an accumulation of sediment. Water impurities can consist of fine particles of soil or sand which will settle out and form a layer of sediment on the bottom of the tank.

A scale of lime will normally form in the tank during operation and will accumulate on the bottom of the tank. Lime is formed from the natural chemicals in the water which precipitate out during the heating cycles. Some water supplies contain more of these elements than others, and the scale buildup will occur more rapidly. Other factors affecting the scale buildup are the amount of hot water used and the water temperature. As more hot water is used, the more fresh water containing the scale-forming elements is brought into the tank. As the temperature of the water increases, the rate of scale deposition will be increased.

Sediment and scale accumulations in the tank will greatly reduce the water heating ability of the heater by reducing effectiveness of heat transfer surfaces. When heating energy from the burner cannot be effectively transferred to the water in the tank, the metal can overheat causing it to lose structural strength.

3.Should a firetube leak for any reason, consult the factory for instructions. Inspect bottom tubesheet on a regular basis to determine if insulation may have pulled away from the tubesheet. Repair or replace as required.

NOTE: Condensate coming from the tubes on a cold start is normal and does not indicate a leaking tube.

4.The tank may have a handhole for inspection and cleaning use. The handhole cover should be periodically removed and the tank inspected for scale buildup. If scale is present, it can be loosened with a high-pressure stream of water. The smaller pieces can be flushed through the drain and the larger pieces removed by hand through the handhole. The frequency of inspections should be determined by the rate of scale buildup. We recommend 30-60 day intervals.

Periodic inspections and check-out of the burner ignition system, control system and gas valve operation should be made and recorded for future reference.

1.Pilot assemblies should be checked by a qualified serviceman using control manufacturer's instructions. Wiring connections on the ignition high voltage wire and flame sensor wire must be tight. Clearance between these wires and metal parts of the water heater or burner must be maintained to avoid possible shorting out. Positions of the electrode, flame sensor and pilot flames are very important and have been set by the manufacturer. If they are loose or if ceramic insulators are cracked or broken, replace the pilot assembly. To replace, remove pilot bracket from bottom of burner, disconnect the pilot gas line and replace pilot assembly on pilot bracket. Replace in reverse order. Do not bend or distort pilot bracket as this determines pilot flame position relative to burner orifices. (See Figure 2-7). Inspect individual burner jets for evidence of overheating. Replace burner jets as necessary.

2.Examine the venting system at least quarterly for proper connections, alignment and the presence of corrosion. Any corroded vent section should be immediately replaced to prevent CO leakage. Re- check vent temperature (step 6, page 5) and correct if necessary.

CAUTION: THE RELIEF VALVE IS A PRIMARY SAFETY DEVICE.

3.The temperature and pressure relief valve should be removed and inspected at regular intervals to determine its condition for safe operation. The openings inside the valve may become restricted by a buildup of scale and become inoperative. If the valve does not open and close properly when tested, it must be replaced with a like kind or one meeting the requirements stated on the rating tag located on the relief valve.

4.Spark ignition system operation should be checked as follows:

Flame failure – Close downstream gas train shutoff valve and determine safety shutdown timing.

Flame signal – Determine flame signal strength in accordance with step 7 on page 5.

PV500-2 06/10 6 Section 2