WARNING
Before manually operating the valve, make sure that a drain line has been attached to the valve to direct the discharge to an open drain. Failure to take this precaution could mean contact with extremely hot water passing out the valve during this checking operation.
FLUSHING PROCEDURE FOR LIME SCALE REMOVAL FROM HEAT EXCHANGER
The amount of calcium carbonate (lime) released from water is in direct proportion to water temperature and usage. The higher the water temperature or water usage and the harder the water (more dissolved calcium carbonate), the more lime deposits are dropped out of the water. This is the lime scale that forms in pipes, water heaters and on cooking utensils.
Lime accumulation reduces the efficiency and longevity of the heat exchanger coil and will cause the water heater to malfunction. The lime scale may need to be periodically removed from the heat exchanger (indicated by the “LC” code on the remote display). The usage of water softening equipment greatly reduces the hardness of the water. However, this equipment does not always remove all of the hardness (lime). The heat exchanger may occasionally need to be flushed to clear out the lime deposits. Use the following procedure and diagram (fig. 13) to flush the heat exchanger and remove the lime scale.
1.Disconnect power to the water heater.
2.Close valves in the cold water inlet and outlet supply.
3.Connect PVC hoses (may use garden hose to the drain valve outlet fittings). Connect a circulator pump to the hose connected to the cold water inlet. See figure 13 for hose and circulator connections.
4.Pour 4 gallons of fresh vinegar into a 5 gallon bucket.
5.Place the ends of the hose into the bucket.
6.Open the drain valves to the hose fittings.
7.Turn on power to the circulating pump and allow the vinegar to circulate through the heat exchanger coil for at least 45 minutes. Heavily limed heat exchangers may require several hours.
8.Turn off power to the circulating pump.
9.Run hose from hot water outlet to a drain.
10.Close the drain valve on the cold water inlet. Leave hot water drain valve open. Open cold water inlet to flush with fresh water.
11.Allow water to flow out of the hose for 5 minutes to flush vinegar from the water heater.
12.Shut off cold water inlet valve. Remove filter screen and clean out any sediment. Reinstall.
13.Close the hot water drain valve. Open the cold water inlet and hot water supply valves.
14.Disconnect the hoses from the drain valve connections.
15.Restore power to the water heater and check operation.
36
