Bradford-White Corp 500-1825 warranty Water Expansion, Pump Performance and Installation

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B4 Volume Water Heater Page 9

Pressure

Relief

Valve

Figure 9. Pressure Relief Valve Location.

Figure 9), must be piped, but not fastened, to a drain or floor sink. The drain pipe must be the same size as the valve outlet and must pitch downward from the valve.

Special attention must be given to relief valve settings in installations where the heater is located on the ground floor of a tall building. The static pressure of the system is elevated and could cause the relief valve to leak. Where no special setting of the relief valve is ordered, the factory will furnish a 125 psi setting. Never reduce the relief valve openings.

3.Pressure relief valve lever must be tripped at least once a year to insure that waterways are clean. When manually operating lever, water will discharge through drain line. Precautions must be taken to avoid contact with hot water and water damage.

4.The weight of all water and gas piping should be supported by suitable hangers or floor stands.

5.Check piping diagrams with local applicable plumbing, heating and building safety codes.

6.All two-temperature systems using temperature valves must have forced recirculation in the low temperature building loop.

7.A check valve installed at the hot water inlet to the tempering valve will prevent cold water from being drawn in reverse through the tempering valve into the hot water.

8.When installing a tempering valve, place at bottom of antithermosyphon loop at least 24" high to prevent excessive hot water from entering mixed water supply. Bring the cold water supply up from the floor to the valve (see Figure 10).

Hot		Tempered Water
Water		24"
Hot				Cold
Water				Water
			Automatic
Storage	Floor
Tank			Tempering
			Valve

Figure 10. Tempering Valve Installation.

2.7Water Expansion

When cold water is heated the water expands. If

no water is being used during the heat-up period the expanded water will normally back up into the city mains.

A water pressure reducing valve installed in the incoming cold water line may act as a check valve and prevent the expanded water from moving backward. This will cause pressure to rise in the heater, which will be relieved by the pressure relief valve.

If the relief valve pops frequently a mineral deposit may build up on the valve seat, causing it to leak.

The following suggestions may solve the problem:

1.Install a properly sized expansion tank.

2.Replace the installed water pressure reducing valve with a suitable valve having a back flow port. These valves have a back flow port which allows water to flow backwards when the pressure in the system exceeds the pressure in the mains.

3.Install an auxiliary small relief valve set at 25 psi less than the main relief valve. The valve must be piped to a drain and may require occasional cleaning. It will bleed off the expanded water and protect the main pressure relief valve from becoming fouled.

2.8 Pump Performance and Installation

1.The factory provided pumps on all Copper Brute heaters are sized to provide proper circulation through the heater and heater-to-tank circulation loop (see Figures 11 and 12). If the heater-to-tank circulating loop does not contain more than 6 elbows or 30 feet of pipe, use pipe fittings in the loop no smaller than the following:

Model	Pipe Size
500 through 850	2"
1010 through 1825	2-1/2"