Lochinvar Hot Water Generator operation manual 6Maintenance, Storage tank maintenance

Hot Water Generator Installation and Operation Manual

6Maintenance

Storage tank maintenance

A new tank installation should have a regular inspection program set up. The first inspection should be within the first three months of operation. Once the tendency to accumulate sediment has been established, the inspection program can be modified to suit the water conditions. Typical inspection programs flush the tank at six-month intervals and clean the tank in yearly intervals.

Deliming solvents or acid type flush agents are not recommended for use in lined storage tanks. These chemical cleaners are usually designed for use in non-potable systems such as heating boilers. These chemicals may be aggressive and cause damage to the tank lining and deteriorate the magnesium anodes supplied in glass-lined storage tanks.

￿WARNING Hot water will be released under pressure. Avoid contact with the hot discharge water

to prevent the risk of severe scald injury.

Flushing the storage tank

Since the mineral accumulation is occurring in an un-fired tank it will be in a soft sediment form. This soft sediment can be removed by a regular flushing of the lower portion of the tank.

To flush the tank, follow these steps:

1.Turn off electrical power to the circulating pump and any other tank accessories.

2.Close the valve on the hot water outlet on the top of the storage tank.

3.Ensure that the drain located on the bottom of the tank is routed to a floor drain with adequate capacity to allow the tank to be flushed.

4.Open the drain valve and allow the incoming cold water to flush the soft sediment out the bottom of the storage tank. Use extreme caution, as the water exiting the tank drain may be very hot. Avoid contact with the hot discharge water to prevent the risk of severe scald injury.

5.Observe the color of the water initially discharged from the tank drain. This water will generally be milky or slightly discolored by the sediment discharge. Allow the drain to run until the water runs clear.

6.Close the drain valve on the tank.

7.Open the hot water outlet valve on the top of the tank.

8.Open an adjacent hot water tap to purge any air that may have entered the storage tank during the draining process. Close the hot water tap if no air discharge is observed.

9.Turn on electric power to the circulating pump and other electrical components if necessary.

10.Observe tank and piping to ensure all components are functioning properly.

Cleaning the storage tank

The mineral accumulation in an un-fired tank will be in a soft sediment form that can be removed by a regular cleaning of the lower portion of the tank. Many tanks will have a hand hole or a larger manway to allow access to the interior of the tank for complete removal of accumulated sediment. An access opening to remove the manway or hand hole is provided in the exterior jacket. The sheetmetal jacket components are removed with hand tools. The opening will be in the bottom portion of a vertical tank and on the end of a horizontal tank (see FIG’s 1 and 2 on page 4 of this manual).

To clean the tank, follow these steps (reference FIG.’s 7 and 8):

1.Close valves from boiler water or steam supply and return or condensate pipes.

2.Turn off electrical power to the circulating pump and other electrical components if necessary.

3.Close the valve on the hot water outlet on the top of the storage tank and the cold water supply to the system.

4.Ensure that the drain located on the bottom of the tank is routed to a floor drain with adequate capacity to allow the tank to be drained.

5.Open the drain valve and open a vent to allow the air to enter the tank (manually opening the relief valve will usually accomplish this). Use extreme caution, as the water exiting the tank drain may be very hot. Avoid contact with the hot discharge water to prevent the risk of severe scald injury.

6.Allow the tank to drain completely.

7.Remove the jacket cover over the manway or hand hole. Remove the bolt(s) securing the tank access opening. Use a flashlight to observe the sediment collected in the tank.

8.Use hand tools to remove all sediment from the interior of the tank. Use care not to damage the interior lining of the storage tank.

9.Use a water hose to flush the remaining sediment from the interior surfaces of the tank and ensure that all debris is removed. Scale or sediment allowed to reach the potable system can foul valves, pumps, strainers, and other water fixtures. Ensure that the tank interior is clean before refilling the vessel.

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