Lochinvar CW 645, CW 745 manual Water Treatment, Water Flow Switch

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

(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

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.

NOTE:

A larger pump must be utilized in situations when the distance between the water and tank exceed those specified.

NOTE:

Care should be taken to measure temperature rise and maintain proper water velocity in the heat exchanger.

NOTE:

If a pressure reducing valve or check valve is in the system a properly sized expansion tank may be required.

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