Lochinvar 402 - 2072 Pump operation, Heat exchanger, Minimum Pump Performance, Ft. Hd

8 Domestic water heaters

TABLE 8C

COMMON WATER MANIFOLD SIZE FOR

MULTIPLE WATER HEATER INSTALLATIONS

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

	Common Manifold Size (Min.)
Number of Water Heaters		Models
	402 - 752		992 - 2072
1	2"		2 1/2"
2	3"		4"
3	3 1/2"		5"
4	4"		6"
5	5"		6"
6	5"		6"
7	6"		7"
8	6"		7"

Pump operation

1.The water heater must have a properly sized circulating pump. This pump is sized to circulate water between the heater and the storage tank only.

2.The pump is sized to the heater input and water chemistry specifications noted in the Water Chemistry section on page 63.

3.The diameter and length of the piping installed between the storage tank(s) and water heater must be properly sized based on the capacity of the circulating pump.

4.The pump must run continuously when the water heater is energized. This is the standard operating system for a water heater.

A pump delay control function with an all bronze pump is installed as standard equipment on all water heater systems. The pump will operate only while there is a “Call for Heat” and for a timed period after the water temperature set point is satisfied to remove any residual heat from the combustion chamber.

5.Lubricate pump to manufacturer’s recommendations. Pump damage due to inadequate lubrication is non-warrantable.

The tank sensor must be installed in the tapping provided in the lower 25% of the storage tank to achieve proper operation. As shipped from the factory, the tank sensor is in the literature package shipped with the unit. Placing the sensor in the tapping provided on the storage tank will improve temperature response and prevent short cycles of operation.

68

Installation & Operation Manual

The standard circulating pump on this water heater 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 specified maximum equivalent number of straight feet for a specified diameter of pipe, non-warrantable operational problems may be experienced.

402 - 752 Models

1/4 HP, 120 VAC, 5.8 Amps

992 - 2072 Models

1/2 HP, 120 VAC, 7.4 Amps

The standard pump selection is based on the following pipe and fittings from the water heater to the storage tank:

6	- 90° elbows	2	- ball valves
2	- unions	1	- cold water tee

Not more than 45 feet of straight pipe.

For every elbow and tee in excess of those shown above, DEDUCT 6.5 FEET from the maximum allowable straight pipe in the heater to tank circulating loop.

TABLE D

MINIMUM PUMP PERFORMANCE

Based on heating potable water with a hardness of 5 to 25 grains per gallon and total dissolved solids not exceeding 350 ppm. See Water Chemistry section on page 63.

Model		GPM	Ft. Hd.
402 - 502 - 652 - 752		55	10
992 - 1262 - 1442 -	1802 - 2072	90	15

When installing multiple water heaters and/or multiple storage tanks, the diameter of the inter-connecting pipe and all fittings must be increased. An increase in pipe diameter will decrease head loss in the system piping and ensure proper flow. Proper pipe size between the heater and storage tank MUST be maintained to ensure that the standard pump supplied on the water heater will maintain desired flow.

When DHW Night Setback is enabled, the system pump output can be used to control a building circulation pump. The pump output will be on during the time Night Setback is not active and will be off when Night Setback is active. A field installed contactor must be used when controlling a circulation pump larger than 1/6 HP.

Heat exchanger

This is a highly sophisticated heat exchanger designed to carry water in such a way that it generates a scouring action which keeps all interior surfaces free from build-up of impurities. The straight-line, two pass design of the copper finned tubes send water into the headers at a properly rated velocity. The configuration of the headers, in turn, creates a high degree of turbulence which is sufficient to keep all contaminants in suspension. This “scouring action” provides greater cost savings for owners. Tubes are always able to transfer heat at peak efficiency. Every surface within this water containing section is of a non-ferrous material, providing clear, clean, rust- free hot water. Straight copper tubes-finned on the outside for maximum heat transfer and glass lined, cast iron, one piece, cored headers make up an entirely rust-proof unit. On all models, header inspection plugs in the heat exchanger can be removed for field inspection and cleaning of copper tubes. The heat exchanger may be removed from the unit.