A.O. Smith 2600 CHECK/CONTROL Water Hardness, Freeze Protection Hydronic Heating Installation

HOT WATER CAN SCALD: Boilers are intended to produce hot water. Water heated to a temperature which will satisfy space heating, clothes washing, dish washing and other sanitizing needs can scald and permanently injure you upon contact. Some people are more likely to be permanently injured by hot water than others. These include the elderly, children, the infirm or physically/mentally disabled. If anyone using hot water in your home fits into one of theses groups or if there is a local code or state law requiring a specific temperature water at the hot water tap, then you must take special precautions. In addition to using the lowest possible temperature setting that satisfies your hot water needs, a means such as a mixing valve should be used at the hot water taps used by these people or at the hot water supply tank. Mixing valves are available at plumbing supply or hardware stores. Follow the manufacturer’s instructions for installation of the valves. Before changing the thermostat setting on the hot water system controller, refer to Table 17.

Hot water temperatures required for automatic dishwasher and laundry use can cause scald burns resulting in serious personal injury and/or death. The temperature at which injury occurs varies with the person’s age and time of exposure. The slower response time of children, aged or disabled persons increases the hazards to them. Never allow small children to use a hot water tap, or to draw their own bath water. Never leave a child or disabled person unattended in a bathtub or shower.

The boiler should be located in an area that is inaccessible to the general public.

Table 17.  RISK OF SCALDS

Water Temperature	Time to Produce 2nd & 3rd
	Degree Burns on Adult Skin

180°F (82°C)	Nearly instantaneous
170°F (77°C)	Nearly instantaneous
160°F (71°C)	About 1/2 second
150°F (66°C)	About 1-1/2 seconds
140°F (60°C)	Less than 5 seconds
130°F (54°C)	About 30 seconds
120°F (49°C)	More than 5 minutes

Should overheating occur or the gas supply fail to shut off, turn off the main manual gas shutoff valve to the boiler.

CHECK/CONTROL WATER HARDNESS

XW Model XP Boilers are approved for use in Domestic Water Heating Systems with a water supply hardness of 0 grains per gallon to a maximim of 12 grains per gallon. Refer to Table 18 for recommend flow rate to maintain scale free operation with up to a medium water hardness. For scale free operation in hard water systems with a water hardness greater than 12 grains per gallon, a water softener must be installed and maintained.

Table 18. 

WATER HARDNESS MEDIUM (0-12 GRAINS PER GALLON)

XW MODEL	∆T ºF	GPM	∆P FEET
NO.
1000	25	76	17.5
1300	25	99	22
1700	25	129	23
2000	25	152	17.5
2600	25	198	22
3400	25	258	23

∆T ºF = Temperature rise ºF at the specified GPM. GPM = Flow rate in gallons per minute.

∆P = Pressure loss through the heat exchanger in feet of head. For systems over 5 grains per gallon; and for scale free operation, boiler setpoint should not exceed 140 ºF.

Note: The factory installed/supplied pump on the above listed model boilers is sized to maintian a 25 ºF ∆T through the boiler when the boiler is firing at 100% fire.

In addtion to the pressure loss through the heat exchanger, the factory supplied pump is sized for an additional 50 feet of equivalent feet of piping between the boiler and a storage tank. All piping between the boiler and the storage tank must be of a pipe size equal to the inlet/outlets of the boiler. Installation differences may slightly change these parameters.

FREEZE PROTECTION (HYDRONIC HEATING INSTALLATION)

1.Determine freeze protection fluid quantity using system water content, following fluid manufacturer’s instructions.

2.Local codes may require a backflow preventer or actual disconnect from city water supply.

3.When using freeze protection fluid with automatic fill, install a water meter to monitor water makeup. Freeze protection fluid may leak before the water begins to leak, causing concentration to drop, reducing the freeze protection level.

INSPECT/FILL CONDENSATE SYSTEM

Inspect/check condensate lines and fittings:

1.Inspect the condensate drain line, condensate PVC fittings and condensate trap.

Fill condensate trap with water:

1.Remove the 2 inch PVC cap with the switch located at the top of the trap.

2.Fill with fresh water until the water begins to pour out of the drain.

3.Replace the cap. Press the cap onto the trap until the cap makes contact with the drain.

The condensate trap must be filled with water during all times of boiler operation to avoid flue gas emission from the condensate drain line. Failure to fill the trap could result in severe personal injury or death.

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