8 Domestic water heaters
If the temperature rise is too high, the water velocity is too low, adjust as follows:
1.Check for restrictions in the outlet of the water heater.
2.Be sure all valves are open between the water heater and the storage tank. Ensure that all ball valves are fully ported.
3.Check the pump to be sure it is running properly and that the pump motor is running in the proper direction.
4.Check diameter and length of the piping between the storage tank and water heater against the head capacity of the circulating pump.
5.Be sure the pipes between the water heater and storage tank are not less than 2 or 2 1/2 inch (63.5mm) diameter (depending on model). To increase flow and decrease temperature rise, increase the piping to 3 inch (76.2mm) diameter (depending on model) to decrease head loss in the piping to the storage tank.
6.Common manifold piping for multiple unit installations will require larger minimum pipe sizes and tank circulating tappings to ensure proper flow.
If the temperature rise is too low, the water velocity is too high, adjust as follows:
Installation & Operation Manual
(continued)
Water chemistry
NOTICE | Water temperature rise and maximum flow |
data is based on heating potable water with | |
| a hardness of 5 to 25 grains per gallon and |
| total dissolved solids not exceeding 350 |
| ppm. |
The required temperature rise and the standard circulating pump are sized based on the heating of potable water with a hardness of 5 to 25 grains per gallon and a total dissolved solids not exceeding 350 ppm. Consult the manufacturer when heating potable water exceeding these specifications. Heating of high hardness and/or high total dissolved solids water may require a larger circulating pump, an optional Cupro Nickel heat exchanger and a revised temperature rise specification based on the water chemistry of the water to be heated. Water with a hardness of less than 5 grains per gallon will usually have a pH which can be aggressive and corrosive causing non- warrantable damage to the heater, pump, and associated piping. Corrosion due to water chemistry generally shows up first in the hot water system because heated water increases the rate of corrosive chemical reactions.
1.Temperature rise can be increased by slowly closing the
2.Sustained high water velocity and low temperature rise may result in pitting or erosion of the copper tubes in the heat exchanger. This is a
3.Once temperature rise has been properly set, return to normal operation.
CAUTION
Temperature rise cannot be adjusted when the burner is firing at less than 100% of rated input.
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