A.O. Smith XB-1000, User Manual

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TAble 2.
WATer hArDNeSS MeDiUM (0-12 GrAiNS per GAlloN)
xW MoDel
No.
∆T ºF GpM ∆P FeeT
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 switch located at top of trap.
2. Fill with fresh water until the water begins to pour out of 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.
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, see Table 1.
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 1. 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 3. operATiNG ChArACTeriSTiCS
Models
(xb/xW)
Manifold pressure Maximum Supply pressure Minimum Supply pressure
Type of Gas inches W.C. kpa inches W.C. kpa inches W.C. kpa
1000, 1300, 1700
2000, 2600, 3400
Natural
Min Fire -0.2 to - 0.3 -0.05 to - 0.07
14.0 3.49 4.0 1.0
Max Fire -3.0 to -3.9 -0.75 to -0.97
Propane
Min Fire -0.1 to - 0.3 -0.025 to -0.07
14.0 3.49 4.0 2.0
Max Fire -3.6 to -4.9 -0.90 to -1.22