Install Instructions

57
Minimum pump performance
This is based on heating potable water with a hardness of
5 to 25 grains per gallon and/or total dissolved solids not
exceeding 350 ppm. See Water Chemistry, page 56.
Heat exchanger
On all models, header inspection plugs can be removed for
field inspection and cleaning of copper tubes. The entire
heat exchanger may be easily removed from the unit.
Potable hot water temperature
control settings
Domestic water temperature
You must take adequate care to prevent
scald injury when storing water at elevated
temperatures for domestic use.
⚠ WARNING
This unit has an adjustable temperature control to maintain the
desired water temperature set point. See Setting Temperature
Control, page 41, for instructions to adjust the temperature
control. The temperature control is factory preset at
approximately 125°F (52°C) or less. Households with small
children or invalids may require 120°F (49°C) or lower
temperature hot water to reduce risk of scald injury.
Operate this high efficiency hot water heater at a temperature
setting high enough to prevent condensing of the products of
combustion on the unit’s heat exchanger or in the attached
venting system. A water temperature setting that is above the
dew point of the gas combustion products should prevent
condensate formation
To guard against scald injury, you must use a
properly sized thermostatic mixing valve to
supply domestic hot water at temperatures
less than 125°F (52°C).
⚠ WARNING
Return water temperatures must not be less
than 140°F (60°C). If lower return water
temperatures are required, follow the
instructions for Low Temperature Return
Water Systems, page 32.
⚠ WARNING
Installation & Service Manual
7 Domestic water heaters (continued)
TABLE 7D
Water Heater Pump Applications
Model
Pipe
Size
Water
Hardness
Grundfos
Pump
Flow
Rate
(GPM)
Head
Loss
(FT)
Temp.
Rise
497
2"
5 to 15 gpg TP44PAB 55 10 15°F
15 to 20 gpg UP 43-110 SF 75 10 11°F
647 2"
5 to 15 gpg TP44PAB 55 10 19°F
15 to 20 gpg UP 43-110 SF 75 10 14°F
747 2"
5 to 15 gpg TP44PAB 55 10 22°F
15 to 20 gpg UP 43-110 SF 75 10 16°F
987 2-1/2"
5 to 15 gpg TP24PAB 90 15 18°F
15 to 20 gpg TP 50-160/2B 115 15 14°F
1257 2-1/2"
5 to 15 gpg TP24PAB 90 15 23°F
15 to 20 gpg TP 50-160/2B 115 15 18°F
1437
2-1/2"
5 to 15 gpg TP24PAB 90 15 26°F
15 to 20 gpg TP 50-160/2B 115 15 21°F
1797
2-1/2"
5 to 15 gpg TP24PAB 90 15 32°F
15 to 20 gpg TP 50-160/2B 115 15 26°F
2067
2-1/2"
5 to 15 gpg TP24PAB 90 15 37°F
15 to 20 gpg TP 50-160/2B 115 15 30°F