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Installation and service manual – Lochinvar 399 User Manual

Page 53

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Installation and

Service Manual

53

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.

FIG. 54 Typical Water Heater Piping with Storage Tank

Pipe Size Requirements

The pipe sizing chart provides minimum pipe size for common
manifold piping to ensure adequate flow.

Circulating Pump

1. The water heater must be connected to a properly sized

pump that circulates water between the heater and storage
tank.

2. Pump is sized to heater input and water hardness. Care

should be taken to size pump correctly. See Water
Chemistry
on page 52.

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 pump to manufacturers recommendations. Pump

damage due to inadequate lubrication is non-warrantable.

5. Standard water heaters are furnished with the following

circulating pump. Mount pump on unit’s inlet water
connection.

1

2"

2

3"

3

3 1/2"

4

4"

5

5"

6

5"

1

2 1/2"

2

4"

3

4"

4

5"

5

6"

6

6"

TABLE-X

Number of Units

Common Manifold

399,999 - 750,000 Btu/hr Models Size (Min.)

Number of Units

Common Manifold

990,000 - 2,070,000 Btu/hr Models Size (Min.)

EXPANSION TANK

(IF REQUIRED)

CIRCULATING

PUMP

RELIEF

VALVE

COLD WATER

SUPPLY

MIXING VALVE

HOT WATER

SUPPLY

RELIEF

VALVE

LOCK-TEMP

STORAGE

TANK

DRAIN

BUILDING

RETURN

399,999 - 750,000 Btu/hr Models

1/4 HP, 120 VAC, 5.8 Amp

990,000 - 2,070,000 Btu/hr Models

1/2 HP, 120 VAC, 7.4 Amp

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