QUICKDRAW→ Steam Heater

Steam Valve Actuator

The steam valve actuator (if applicable) is sealed and requires no maintenance. Durability of valve stems and packing is dependent upon maintaining non-damaging water conditions. Inadequate water treatment or filtration can result in corrosion, scale, and abrasive particle formation. Scale and particulates can result in stem and packing scratches and can adversely affect packing life and other parts of the Hydronic system. Contact the manufacturer for replacement packing and stem & plug assembly.

Tank

Scale will normally form in the tank during operation and will accumulate on the bottom of the tank. The natural chemicals in the water forms scale which precipitate out during the heating cycles. Some water supplies contain more of these chemicals than others do, and the scale buildup will occur more rapidly. Other factors affecting the scale buildup are the amount of hot water used and the temperature of the water. The more hot water used the more fresh water containing the scale-forming chemicals enter into the tank. As the temperature of the water increases, the rate of scale deposited also increases. The frequency of inspections will be determined by the rate of scale buildup. Until the appropriate inspection and cleaning frequency is established, initially inspect the tank every six months or more frequently if higher scaling conditions are present.

Flush the tank at two or three-month intervals depending on water conditions in your location to help prevent the accumulation of scale. To flush: turn off electrical disconnect switch to prevent the unit 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.

WARNING: Since PVI cannot control the use of the water heater, water conditions, or maintenance, the warranty on the water heater does not cover poor performance, structural failure, or leaking due to an excessive accumulation of scale.

Cleaning the Heat Exchanger (refer to figure on page 10)

1.Do not open until all pressure is removed, the unit is drained and the equipment surfaces cooled to ambient temperature.

2.Heat exchangers subject to fouling or scaling should be cleaned periodically. A light sludge or scale coating on the tube greatly reduces its effectiveness. A marked increase in pressure drop and/or reduction in performance usually indicate cleaning is necessary.

3.Tube bundle removal:

a.When practical, leave tube bundle attached to collar assembly and remove by unbolting collar assembly from tank.

b.During bundle removal, the dead weight of bundle should never be supported on individual tubes or contact any lined interior tank surface. Following removal, rest the bundle on the tube sheet, support plates, or wood blocks cut to fit periphery of the bundle.

c.Tube bundles may be raised using slings formed by bending light sheet metal into a “U” form and attaching lifting lugs to the ends of the sheets. Baffles can be easily bent and damaged if dragged over rough surfaces.

d.Before reinserting the tube bundle into the unit, place the ring/tank gasket over the end of the tube bundle and bring forward to the backside of the tube sheet.

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