Lochinvar COPPER-FIN CW 745 - Manual (Page 15)

Due to pump capacity the following
specifications cannot be exceeded
when using the standard pump:
• Not more than 45 feet of straight pipe.
• 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.
WATER TREATMENT
In hard water areas, water treatment
should be used to reduce introduction
of minerals into the system. Minerals
in the water can collect in the heat
exchanger tubes causing noise and
inefficient operation. Excessive build-up
of materials in the heat exchanger can
cause a non-warrantable failure.
Acceptable Water Quality Levels
Maximum Water Hardness = 25 Grains
Minimum Water Hardness = 5 Grains
Maximum Total Dissolved Solids = 350 PPM
Range of Acceptable pH = 7.2 to 7.8
Standard production Lochinvar water heaters
are designed to operate free of impurity
build-up in the heat exchanger when
properly installed and operated under the
specified water quality conditions.
For installation in areas outside these
parameters, please consult the factory.
Water Flow Switch
Due to the low water content (between 1
and 6 gallons) of the copper finned tube
heat exchanger, a flow switch is factory
installed as a low water cutoff device on
models CW495 thru CW2066.
The flow switch is installed in the outlet
piping from the water heater and wired in
series with the ignition system safety controls.
In most localities, a flow switch is acceptable
as a low water cutoff device on water
heaters requiring forced circulation. It is
prudent to verify acceptance with the local
code official.
If the local water quality levels are slightly
higher than recommended, it may be
possible to use a copper-nickel heat
exchanger. With copper-nickel being a
harder alloy, flow rates can be safely
increased to keep the greater water
hardness and TDS in suspension. The flow
rate can be increased up to 25% faster than
the flow rates listed above.
L o c h i n v a r D E S I G N E R ’ S G U I D E C O P P E R - F I N W A T E R H E A T E R 6 1 5 - 8 8 9 - 8 9 0 0 1 3
NOTE:
Care should be taken to
measure temperature
rise and maintain proper
water velocity in the
heat exchanger.
NOTE:
A larger pump must be
utilized in situations
when the distance
between the water
and tank exceed
those specified.
NOTE:
If a pressure reducing
valve or check valve is
in the system a properly
sized expansion tank
may be required.
(TABLE G) – REQUIRED PUMP
PERFORMANCE FOR WATER HARDNESS
OF 5 TO 25 GRAINS
MODEL GPM FT. HD AMP DRAW HORSE VOLTAGE/
POWER PHASE
CW 495-745 60 10 5.8 1/4 120/1
CW 986-2066 90 15 7.4 1/2 120/1