Install Instructions

7 Domestic water heaters
TABLE 7C
Pipe Sizing Chart
497 - 747 987 - 2067
Number of
Units
Common Pipe
Size (Min.)
Number of
Units
Common Pipe
Size (Min.)
1 2'' 1 2 1/2''
2 3'' 2 4''
3 3'' 3 4''
4 4'' 4 5''
5 5'' 5 6''
6 5'' 6 6''
Water chemistry
The required temperature rise and the standard pump sizing
are based on the heating of potable water with a hardness
of 5 to 20 grains per gallon and a total dissolved solids not
exceeding 350 ppm. Consult the appliance manufacturer
when heating potable water exceeding these specifications.
Heating of high hardness and/or high total dissolved solids
water will 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 low 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.
Pipe size requirements
Table 7B, pipe sizing chart provides the minimum pipe size
for common manifold piping to ensure adequate flow.
Required temperature rise
Based on heating potable water with a hardness of 5 to
20 grains per gallon and/or total dissolved solids not
exceeding 350 ppm, see Water Chemistry, this page.
Installation & Service Manual
Circulating pump
1. The water heater must be connected to a properly sized
pump that circulates water between the heater and
storage tank.
2. The pump is sized to heater input and water hardness.
Care should be taken to size the pump correctly. See
Water Chemistry, this page.
3. The water heater is equipped with a factory-supplied
pump delay system in accordance with the requirements
of the latest edition of ASHRAE 90.1.
4. Lubricate the pump to the manufacturer’s
recommendations. Pump damage due to inadequate
lubrication is non-warrantable.
5. Standard water heaters are furnished with the following
circulating pump. Mount the pump on the unit’s inlet
water connection.
Models 497 - 747
1/4 HP, 120 VAC, 5.8 Amps
Models 987 - 2067
1/2 HP, 120 VAC, 7.4 Amps
This pump is sized based on installation of a single storage
tank and heater in close proximity. If the number of fittings
and straight pipe exceeds the quantities shown in this section, a
larger pump will be required.
The standard pump selection is based on the following pipe and
fittings from the unit to the storage tank:
• 6 90° elbows
• 2 unions
• No more than 45
feet of straight pipe.
• 2 ball valves
• 1 cold water tee
NOTICE
For every elbow and tee in excess of those shown
above, deduct 5 feet from maximum allowable
straight pipe in heater to tank circulating loop.
56
NOTICE
1. Do not use the appliance to directly
heat swimming pool or spa water.
2. At initial fill and during water heater
start-up and testing, check system
thoroughly for any leaks. Repair all leaks
before proceeding further.
3. When water hardness levels are less
than 5 gpg or 85.5 mg/l, the following is
recommended:
a. Flush and clean existing water heating
system prior to installation.
b. Inspect and, if necessary, replace the
anodes in any existing tanks.
c. Install a Y-strainer on the inlet of each
water heater as detailed in this section.
d. Limit the run time of the hot water
recirculation loop.
e. Filter the hot water recirculation loop
to a level of 10 microns. CAUTION:
Check recirculation pump size to verify
it is sized for filter addition and upsize if
necessary.
4. When water softener is required, a
Template Assisted Crystallization system
is recommended.